Abalone
A genus of shellfish from the haliotidae family of edible rock-clinging gastropod mollusks that have a flattened shell slightly spiral in form, lined with mother-of-pearl, and with a row of apertures along its outer edge. The abalone shell is a richly colored sea shell that when polished makes a beautiful ornament. It is used as a popular inlay material in musical instruments such as guitar and bass.

Action
A term used to describe the way a musical instrument plays. Its use is highly varied in the industry, but in a general sense it refers to the playability of an instrument or how well it functions mechanically. It often specifically relates to how much force is required to play the instrument. "Piano action" or the more generic "weighted action" is used to describe some keyboards, for example, where it means that the keyboard itself feels sort of like a piano in its mechanical operation, as opposed to an unweighted synthesizer style action. You have to press harder on a piano to make sound, but this "feel" is very important to players. There is also the "hammer action," which pertains to a keyboard that actually uses a hammer mechanism internally to more closely simulate the feel of a real piano keyboard. Hammer, weighted, and piano action are terms that tend to be used interchangeably even though they aren't exactly the same thing. In guitars and basses the action again refers to how the instrument plays, and specifically to how much down force is required on the strings to properly press them against the frets. A lighter or lower (as in strings down closer to the frets) action is considered easier to play, but just like the piano some players don't like it to be too easy. What constitutes a "good" action is very subjective and each player typically has his own tastes.

Alnico
A compound word drawn from Aluminum, Nickel, and Cobalt. Alnico (AlNiCo) is a powerful permanent magnet alloy containing iron, aluminum, nickel and one or more of the elements cobalt, copper, and titanium. Alnico magnets have been used in loudspeaker construction since the 1940s, when a particularly high-energy formula (Alnico V) was developed; it had a much greater energy-to-weight ratio than common ferrite (iron) magnets. Electric guitar manufacturers also were (ahem) attracted to Alnico magnets for pickups due to their consistency and even distribution characteristics. Two different formulas are commonly used - Alnico II and Alnico V.

Amplifier, Instrument
An instrument amplifier is an electronic amplifier designed for use with an electric or electronic musical instrument, such as an electric guitar or electric piano/keyboard. Instrument amplifiers come in two main forms. The combo amplifier contains both the amplifier and suitable loudspeakers in a single unit. In the other form, the amplifier is separate from the loudspeakers, and joined to them by cables. The separate amplifier is called an amplifier head and is commonly placed on top of one or more loudspeaker enclosures, the amplifier head and loudspeaker enclosures together forming an amplifier stack. An amplifier stack consisting of a head and two loudspeaker cabinets is sometimes called a double stack. The first instrument amplifiers were probably guitar amplifiers designed for use with electric guitars. Traditional guitar amplifiers provided a great deal of treble boost, and no high treble or low bass response at all. Some better models also provided a spring reverb and/or an electronic tremolo unit, which electric guitarists (following the lead of Fender) have confusingly always called vibrato, and similarly they call a device designed to produce real vibrato a tremolo arm. Nowadays called a whammy bar) Guitar amplifiers were at first used with limited success with bass guitars and electronic keyboards, but it was quickly recognized that other instruments had different requirements to the electric guitar. A wide range of instrument amplifiers are now available, some general purpose and some designed for specific instruments, and even for particular sounds. These include:

• Traditional guitar amplifiers, with a clean undistorted sound, a sharp treble roll off at 5KHz or less and bass roll off at 60-100Hz, and often built-in reverb and "vibrato" units.
• Rock-style guitar amplifiers, intended for distortion.
• Bass amplifiers, with extended bass response and tone controls optimized for bass guitars.
• Keyboard amplifiers, with very low distortion and extended, flat frequency response in both directions.
• Acoustic amplifiers, similar in many ways to keyboard amplifiers but designed specifically to produce an "acoustic" sound when used with acoustic instruments with built-in pickups.

Anti-node
The opposite of a node. When standing waves occur, there are positions in space relative to the wave, called nodes, at which there is no movement at all. The wave interferes with itself to create this instance of opposition (e.g., a wave reflecting off of a wall and back into its own path). Nodes are spaced one-half wavelength apart. On either side of a node is a vibrating antinode. The antinodes alternate in the direction of the wave's displacement so that the wave at any instant resembles a graph of a sine wave. On a guitar string the nodes are the places on the string that best produce harmonics - particularly at the 12th fret. Touching the antinodes damps the sound.

Backline
A general term that includes all necessary band gear including guitar, bass and keyboard amplifiers, drums, microphone stands and cables, sometimes also encompassing keyboard instruments and rarely guitars and basses. It excludes any part of the house or stage monitor sound systems, which serve to amplify the backline gear. Originally a bit of tour jargon, the term is now accepted in touring groups' contract riders and insurance forms. Note that the term refers to the equipment itself and NOT to a specific area of the stage. Backline gear can be offstage, under the stage or in other locations.

Balanced
In audio, the opposite of Unbalanced. For us balanced refers to a type of AC electrical signal having two "legs" independent of ground. One is generally considered positive (+) and the other negative (-) in voltage and current flow with respect to ground. Unlike unbalanced audio lines there is no "signal" carried in the shield or ground connection unless there is a fault. The main benefit is that any noise that gets induced into the line will be common to both the positive and negative sides and thus canceled when it arrives at its destination, assuming the destination is balanced. This phenomenon is called "Common Mode Rejection" and basically just means that any signals common to both the positive and negative legs of balanced lines get canceled. This happens because when the receiving device looks at the signal the common noise actually shows up as out of phase with itself, and gets cancelled. Think of it as if the negative (-) signal gets inverted to positive (+) before use, which puts the desired audio signal in phase with the already positive other leg and at the same time causes the undesired common noise to become out of phase with itself. Clear as mud? Balanced lines are generally much better for long cable runs due to their ability to reject induced noises. XLR and TRS type cables are designed to transmit balanced audio from one balanced device to another. A standard 1/4-inch guitar cable is an example of an unbalanced cable. Another (newer) application of balancing that is becoming popular in audio systems is the idea of balanced power systems. Fundamentally the concept is the same. There is a positive and negative (with respect to ground) leg of electricity at every electrical outlet. The idea is that the power supply of any devices connected can then reject any noise induced on the AC line and thus will produce cleaner audio. We'll talk more about balanced AC systems in the future.

Barre Chord
The Barre chord, (From the French term barre), is a guitar player's technique that involves placing the left hand index finger over two to six strings in the fingering of a chord. The great advantage of using barre chords is that they are "moveable shapes" that can be applied at practically any fret.

Bass
Technically, the lowest-pitched part of any musical work. The word comes from the Latin bassus, meaning "low" or "thick." In vocal music, a bass is the lowest range of the male voice; it generally extends from low E or F (an octave and a half below Middle C) to Middle C. It's important to remember that no two people necessarily have the same range, so this is an approximate value. The term "bass" is also used to identify the lowest-pitched members of many families of musical instruments, such as bass clarinet, bass trombone, bass drum, etc. There are even bass flutes. "Bass guitar" is a correct term for the instrument with strings tuned E, A, D, G - one octave lower than the first four strings of a traditional guitar. However, a "bass violin" is more accurately a "double bass," with strings tuned two octaves below the violin. The term "bass," though, has gained general acceptance.

Bleed
In audio, bleed is the leakage of one audio source's output into another audio source's input. This can happen onstage, such as a drum or cymbal's sound bleeding into a guitar amp mic, or in the studio, such as the output from a singer's headphones leaking into the vocal mic. Some solutions to reduce bleed include: mic selection and placement - using a cardioid or supercardioid mic on a source to reject signals from other directions; use of noise gates to attenuate mic sensitivity so they don't pick up outside noise; and optimizing the gain stage of your mixer and peripherals to achieve an ideal signal-to-noise level.

Body Pack
In the world of wireless performance a body pack is the device a performer wears somewhere on his or her body that houses the electronics that handle sending a signal to a remote receiver or, as in the case of personal monitoring systems, receives a signal from a remote location. Typically body packs hold a battery and some combination of electronics that do the transmitting or receiving, and amplifying. Some wireless systems do not require a body pack as all of these electronics can be housed right inside of a microphone or a small plug that can be connected directly to a guitar or other musical instrument.

Bolt-On Neck
A guitar neck that is secured to the body by a series of bolts or wood screws. This term is almost always applied to solid body electric guitars; Leo Fender's first electric guitar, which would eventually be called the Telecaster, was the first prominent bolt-on neck design. Ironically, Fender didn't use bolts at all - his guitar neck was attached to the slab body with four wood screws, with the joint further strengthened by a metal cover plate. Although most acoustic guitar manufacturers use a glued set neck, Taylor utilizes a patented bolt-on design in which two bolts pass horizontally through the body and into the neck. A third, shorter bolt passes vertically into the heel of the guitar neck.

Bridge
A part of a stringed instrument such as guitar, bass, etc. found at the opposite end of the guitar from the nut, down on the body. One of the functions of the bridge, in addition to simply holding the strings in place, is to transmit their vibrations to the top of the instrument, or more accurately, to the instrument's soundboard. Bridges come in many different shapes and sizes and may be made from a variety of materials depending upon the instrument in question, and often come in significantly different shapes and sizes within one type of instrument, such as guitar. Most bridges employ some type of "saddle," which is the point where the vibrating part of the strings terminate. Sometimes the position and height of these saddles are individually adjustable for each string, which can be of great help for adjusting things such as the instrument's intonation. Bridges may or may not include an actual termination point for the string, again depending upon the specific design in question.Bridge is also known musically as a transitional passage connecting two sections of a composition. Some would define it as a second melody in a song that separates the main melody from its repetition.

Bucking
Refers to the cancellation of one signal or frequency component of a signal by another signal of equal amplitude but opposite polarity. Sometimes this is called phase cancellation. It also is a phenomenon that is part of the sound of a phaser or flanger. As they sweep through their range various frequencies are accentuated or (nearly) cancelled producing their characteristic "whooshing" effect. Hum bucking, as in hum bucking guitar pickups, is the bucking of frequencies we associate with hum (60 Hz in the United States). In this case the cancellation is of EMI that is being picked up by the guitar's pickup, which is acting as a transformer picking up various fields nearby.

Capo
A capo (short for capotasto, from Italian, literally; 'head of fingerboard') is a movable bar attached to the fingerboard of a fretted instrument to uniformly raise the pitch of all the strings. There are several different styles of capo available, utilizing a range of mechanisms, but most use a rubber-covered bar to hold down the strings, fastened with a strip of elastic or nylon, a cam-operated metal clamp, or other device. The use of a capo is considered by some people to be a crutch for technically inferior players. While it can be used for this purpose (for example, allowing a novice guitarist to play chords in the relatively difficult key of Ab by playing the much simpler chord shapes for the key of G), it also facilitates making use of the instrument's natural qualities in certain keys and allows for the use of techniques and sounds that would otherwise be unavailable. Because of the different techniques and chord voicings available in different keys, the same piece may sound very different played in D or played in C with a capo at the 2nd fret (at the same actual pitch). Additionally, the timbre of the strings changes as the scale length is shortened, suggesting the sound pf other short-scaled stringed instruments such as the mandolin. Therefore the use of a capo is as much a matter of artistic expression as of technical expediency. The use of a capo also obviates the need to learn a song in several different keys if accompanying singers who sing at different pitches. For guitar playing, some styles such as flamenco and folk music make extensive use of the capo, while it is used very rarely if at all in other styles such as classical and jazz playing.

Center Tap
In coils and transformers a center tap is a tap (see WFTD Tap) at the center of the winding of wire, which puts it at the halfway point of the overall impedance and voltage of the coil. Center taps are often used to provide a zero reference (kind of like ground, but different) for the two sides of a differential or balanced circuit. For example, if a center tap was taken from a transformer that supplied 220 volts you would end up with two "legs" that each provide 110 volts (as is often the case in common household electrical service in the U.S.). The AC signal provided between the center tap (which is common to each leg) and each end of the coil will be at the opposite polarity, Balanced AC supply devices commonly found in recording studios operate by tapping the center of a transformer running at 120 volts, which provides two 60 volt legs in a differential configuration. In audio circuits center tapped transformers and coils can be used to create balanced circuits. The coil tap function of a guitar's electronics also provides a similar function. But in many of those cases when the coil is "tapped" (see WFTD Coil Tap) the user is really just turning off one half of a differential system that always has a center tap. This is common for guitarists because it allows a humbucking pickup to also be able to work as a single coil pickup.

Coil Tap
In general a coil tap is an access point somewhere along the wire that is wound in a coil or transformer. The tap could be anywhere along the wire, and the resulting voltage present at the tap will be related accordingly. Transformers may have their coils tapped to provide different voltages in a power supply that may be required for the operation of some device, for example. A coil may also be tapped at its halfway point, which in effect produces two coils of equal size. If the middle point is connected to ground, or some zero voltage reference, the two ends of the coil will appear to have equal, but opposite in polarity, voltages with respect to that center tap. The is one way balanced or differential signals can be created. Similar results can be achieved by taking a tap from a point between two identical coils wired in series with one another. In guitars a coil tap is a case of the latter. Humbuckers, or dual coil guitar pickups generally produce a fatter, warmer sound than their single coil counterparts. However, single coil pickups are known for their crisp and bright sound, and also for their propensity to pick up stray EMI. By the late 1970s manufacturers realized that musicians wanted both kinds of sound - crisp and bright along with fat and warm - and so they developed ways to split the coils, which is known as coil tapping. A selection between dual coil (humbucking) and single coil is provided by some type of switch on the guitar. Normally selection of the coil tapped mode causes one of the coils of a dual coil pickup to be turned off, and the signal is obtained between the other coil and the “tap,” thereby making it into a single coil pickup. There are some other, more sophisticated designs that allow the single coil sound to be achieved without giving up the second coil – and thus the benefit of humbucking – but those techniques aren’t, by definition, considered coil tapping, though they may be referred to as such.

Combo Amp
In addition to types of amplification such as solid state and tube, guitar amps come in different configurations. Combo Amps (short for combinations) are self-contained units containing the amplifier and speaker in one cabinet, as opposed to a separate amp “head” and cabinet.

Compensation (guitar)
Whenever a string is pressed to a fretboard, the tension of the string is increased. This causes the fretted note to be slightly sharp compared to the open string note. This must be compensated for. To compensate for this sharpness, the distance from the nut to the bridge saddle is made slightly longer than the stated scale length for the instrument. This lowers the pitch of the fretted notes slightly. The amount of compensation needed depends on how far the string must be pressed to the fingerboard (action), the mass/thickness/gauge of the string, the tension (tightness) of the string, and the string length. When you look at the bridge of most instruments, you see evidence of compensation, for example; when you see the guitar's saddle at an angle to the strings rather than perpendicular to them. On a mandolin, some guitars and banjos, and electric guitars in particular, the saddle is carved or adjusted so each string bends over it at a different distance from the nut. The exact amount is usually determined by comparing the pitch of the note fretted at the 12th fret to the pitch of the harmonic at the 12th fret. When the two match, you have found the compensated position of the bridge saddle for that string.

Compressor
A compressor is a device that reduces the dynamic range of an audio signal. First a threshold is established. When the audio signal is louder than this threshold, its gain is reduced. The amount of gain reduction applied depends on the compression ratio setting. For example, with a 2:1 ratio, for every 2 decibels the input signal increases, the output is allowed to increase only 1 decibel. A variety of other parameters in the compressor will also affect its performance processing specific signals; attack time, release time and others are very important.There are a variety of uses and applications for compressors, the most obvious one being to control the dynamic range of a live performance so that it will fit into the fairly narrow dynamic range of recorders, etc. Other applications include making a signal's average level higher, increasing the apparent sustain on a guitar, evening out a vocal or bass guitar performance, fattening up sounds, and on and on. The list of possibilities is extensive!

COSM
Abbreviation for Composite Object Sound Modeling. COSM is a powerful modeling technology that Roland premiered in 1995 with the VG-8 V Guitar System, and continues in the newer VG-88 system. It enables guitarists to emulate a range of classic and modern guitars, amps, cabinets, and microphones, plus it can produce "futuristic" synth-like tones. Today COSM can be found in keyboards, digital recorders, mixers, etc. It can model rotary effects, different speaker colorations, and can even approximate expensive microphones using just an ordinary dynamic mic. Its name comes from "composite object" because its core function revolves around breaking audio producing or reproducing devices down to their component parts and creating a set of instructions to emulate how these various parts interact with each other to produce a new composite that can be dynamically controlled. Of course, that's what all modeling is, but Roland coined this name to call attention to it.

Damping
In physics this relates to decreasing the amplitude of a wave, whether represented electrically or mechanically. In acoustic instruments we refer to the mechanical context, where we may dampen or reduce the vibration of strings on a piano, guitar, bass, etc. Applying muffling to drums and other instruments would also qualify. In acoustics this could refer to reducing sympathetic vibrations or the acoustic reflectivity of something. For example, applying acoustic absorbers to a wall surface or the inside of a speaker cabinet effectively dampens or reduces reflections.

Double Tracking
The process of recording a track, then recording a second track while listening to the first and duplicating it. When the two tracks are played back together, the result is a slight "chorusing" and fattening of the signal due to minor pitch and timing differences between the two performances. Double tracking is an effective tool, and has been used extensively in most pop music styles. Vocals, melodic parts, rhythm guitars, and solos are common candidates for doubling, tripling or even more (you can never have too many rhythm guitar tracks in our opinion).

Dreadnought
A term used to describe large sized acoustic guitars that were known for their formidable volume and booming bass. While considered a generic term today, the Dreadnought guitar was an original creation of C. F. Martin & Co. The very first Dreadnought guitars (named for a class of World War I-era British battleships, "Dreadnought") were manufactured by Martin for the Oliver Ditson Company, a publishing firm based in Boston that was also a leading music retail chain in the area. The Ditson Company went out of business in the late 1930's, and Martin incorporated the Dreadnought into its line of guitars. Today, the model is a dominant factor in the Martin line, and every maker of acoustic guitars, both domestic and foreign, has introduced a version of the original Martin design.

Dynamic (Microphone)
A dynamic mic is one in which audio signal is generated by the motion of a conductor within a magnetic field. In most dynamic mics, a very thin, light, diaphragm moves in response to sound pressure. The diaphragm's motion causes a voice coil which is suspended in a magnetic field to move, generating a small electric current. Generally less expensive than condenser mics (although very high quality dynamics can be quite expensive), dynamics feature quite robust construction, can often handle very high SPLs (Sound Pressure Levels), and do not require an external power source to operate. Because of the mechanical nature of their operation, dynamic mics are commonly less sensitive to transients, and may not reproduce quite the high frequency "detail" other types of mics can produce. Dynamic mics are very common in live applications. In the studio, dynamics are often used to record electric guitar and drums.

Effects Loop
A signal path out of one piece of gear, through an effects unit, and back into the first device. It effectively is a loop, with an effects processor in the middle. When you send a signal out of a mixer on an aux send to a reverb, and then bring that signal back to the mixer you have created an effects loop, though we rarely call it that in those circumstances. Most of the time the verbiage is used in the context of guitar or bass amps, or guitar or bass preamps. Many of these have a dedicated insert point designed to be used with some outboard processor. In most cases they work just like the insert of a mixer: plugging something in breaks the internal signal routing to send the signal through the external loop.

Electrophone
An electrophone is any musical instrument that produces sound primarily by electrical means. It is one of the five main categories in the 1961 revision of the Hornbostel-Sachs scheme of musical instrument classification (though it was not included in the original scheme published in 1914). The other four are idiophone, membranophone, chordophone and aerophone. Any instrument producing sound purely by electric means is an electrophone, but the term was not originally applied to instruments where electricity was only used to amplify a sound produced by conventional measures (so the electric guitar, for example, would be classified as a chordophone, not electrophone).

Faraday Shield (or Faraday Cage)
An electrostatic shield named after its inventor Michael Faraday. It is made by placing conductive material (often aluminum or copper) around some device and connecting that material to ground. The better the conductor (in other words, the less resistance it has) the better shield it will be. The braided wire around the conductor(s) in audio cable is an example of a Faraday Shield. They are also used in transformer designs (to prevent capacitance between the primary and secondary windings), and the most sensitive electronics on circuit boards, in which case they are often deployed as a hard aluminum cage around said components. It is also common to use this shielding technique around sensitive guitar electronics to reduce the guitar's sensitivity to stray fields.

Fingerboard
A thin piece of wood that forms the smooth playing surface on the neck of a stringed musical instrument such as guitar, bass, violin, etc. against which the strings are pressed in playing. It can be fretless, as in the violin family, or fretted, as in guitars, banjos, etc. (in which case it's often called the "fretboard"). Fingerboards are usually made of woods like rosewood, ebony, or other dark woods, though sometimes maple is used.Fingerboard is also sometimes used to denote a bank of keys on a musical instrument such as a keyboard.

Fret
A bar or ridge (usually made of metal) across the fingerboard or neck of a musical instrument; when the string is stopped (pressed) by a finger at the metal bar it will produce a note of the desired pitch. Frets are arranged on instruments to produce specific musical pitches, usually of some musical scale. On the typical guitar or bass each fret represents one semitone or half step.

Front Loaded
A speaker cabinet design characterized by the speaker being mounted to the front of the cabinet or baffle. This configuration is very popular with studio monitors, guitar and bass cabinets, stereo speakers, and many types of PA enclosures. The other prominent design used over the years is horn loading, which is where the speaker is set back in the throat of some type of horn-like configuration. Each has its own strengths and weaknesses and is appropriate in different circumstances.

GoBo
Short for "Go-Between." A gobo basically forms a type of barrier: sometimes this can be between a light source and an area to be lighted where you want to keep the light off of part of it, or it can be to form a barrier for sound such that a particular sound source is shielded from a microphone during recording. Gobos are often used in recording studios for just this purpose. Say you have an acoustic guitar and a drum set in the same room. In order to help reduce the amount of drums bleeding into the acoustic guitar mic sound, absorbent panels, or gobos, are place between the drums and the guitar mic.

Half Step
The smallest commonly used interval of musical distinction in western music. An octave is divided into 12 such intervals. On the piano a half step is the distance between any two adjacent keys, whether black or white. On guitar each fret represents a half step. A half step is also known as a semitone.

Hardwired
A term used to characterize the configuration of mechanical or electronic components that cannot be changed by the user. It is also used figuratively to refer to similar situations in software, where the program does not permit altering the routing of data or other signals. The term actually predates these uses, and has been used to make the distinction between circuits that were wired by connecting lots of physical wires together between all the components versus putting the components on a circuit board where the connections were etched into the board. If you take apart a very old guitar amp, for example, you will find all the connections hardwired. Each component has one or more wires connected to its terminals that run to other components. In a modern design you will see components placed on a board. The other side of the board will have a (sometimes complex) series of "traces" that connect all the components together in a way that makes the device function. The hardwiring method fell out of favor because as designs became more complicated they were more difficult to build and much more difficult to service.

Harmonic
In audio a harmonic is sort of the opposite of a fundamental, though technically the fundamental is also considered a harmonic. Pretty confused? Harmonics of a particular waveform are multiples of its fundamental frequency. The first multiple is obtained by multiplying the fundamental frequency by one (1). Therefore in a strict sense the first harmonic is the same value (frequency) as the fundamental. The rest of the "harmonic series" (2x, 3x, 4x, etc.) of a sound make up the basic character, or timbre, of the sound based upon all of their relative amplitudes (levels).In the discourse of guitar playing (though this concept applies to all stringed instruments) a harmonic is a technique where a string is made to sound at some multiple of its fundamental frequency. This is achieved by applying light pressure at some point along the length of the string and exciting it into vibration (usually with a pick). With this technique the fundamental frequency of the string is (nearly) muted by the pressure, but depending upon where along the length of the string pressure is applied the harmonics are excited differently. This has the effect of changing the apparent pitch of the note played, but the notes always have some relationship to the fundamental frequency of that string at its given tension and length. This action is fundamentally (no pun intended) different than fretting a string, which actually changes the length of the string and creates a new fundamental frequency.

Headstock
The part of a guitar at the "other" end of the neck from the body. The headstock is traditionally used for supporting the mechanical assemblies used to wind the strings, although in some modern designs string winding is done at the bridge.

Hi-Z
As the letter Z is the commonly agreed upon abbreviation for impedance, then Hi-Z simply refers to “hi-impedance.” This refers to the input or output impedance of a device (in our cases an audio device). Precisely what Hi-Z means, and how it is applied in the audio industry, is not entirely concrete. In general devices with impedances up through 600 ohms are said to be “low impedance,” while devices with impedances of several thousand ohms and up are considered “high impedance.” Typically we only come in to contact with these generic terms on microphones (usually low cost microphones), some direct boxes, and certain types of line inputs (on mixing boards, some tape decks, etc.). A typical guitar, for example, generally needs to be connected to a Hi-Z input. Otherwise the electronics will be “loaded down” and the sound will be significantly altered. A Hi-Z microphone – which we don’t encounter very often in pro audio (we generally use low impedance mics) – definitely needs to be connected to a high impedance input, and even then the cable length can’t be more than 10 or 20 feet before the signal degrades.

Hum
A normally undesired low-pitched noise that can be heard in an audio signal. The source of this noise can be a ground loop or AC electrical induction from power lines that are too close to audio lines. This phenomenon is often referred to as "60-cycle hum." Here's why: In the Americas and most of Asia alternating current is generated with a frequency of 60Hz. This also creates strong 2nd and 3rd harmonics at 120Hz and 180Hz. Europe and the rest of the world use 50Hz mains, so the harmonics fall at 100Hz and 150Hz. We say "normally undesired" because some contemporary musicians - most of them electric guitar players - consider hum to be a part of their signature sound. In fact, some digital effects units and amp modeling devices include a digitally recreated hum in their presets.

Humbucker
A type of guitar pickup where two coils of wire and two magnets are used, as opposed to a "single coil" pickup. The humbucker is made so the two coils of wire are out of polarity with each other and each is wound around a magnet of opposite polarity. The humbucking pickup has two distinct advantages over standard single coil pickups. They are higher output and less hum and noise. The higher output occurs simply by having two pickups working in conjunction with one another, even though the two coils and magnets are of opposite polarity. This works because it's sort of a double reversal (like two negatives make a positive), which leaves the two voltages created by the string's vibration over each coil in polarity with each other. The backwards magnet throws it out of polarity, but the coil being wound backwards as well reverses it again, leaving it in phase with the voltage on the other coil. But hum and noise that can be induced into the coil of wire through electromagnetic radiation (EMI) -- as opposed to moving a string through the magnetic field created by the magnet -- get canceled when the two signals are combined because the two coils are out of polarity with each other. Humbucking pickups are known for a certain type of "thicker," heavier sound and aren't preferred by guitarists in all situations.

Humbucking
A process of injecting a certain amount of hum into a signal at an opposite polarity of hum already present. The net result is cancellation of the hum thereby producing a clean signal. Humbucking is normally provided by a coil, which is very efficient at picking up hum producing electromagnetic fields (EMI) such as those produced by high power equipment like lights, motors, etc. The concept was applied to guitars many years ago. It is called the humbucking pickup (a.k.a. humbucker). Guitar output signals are generally very easily compromised by stray fields due to the magnet and coil nature of the typical guitar pickup. The humbucker provides cancellation of the hum right at the source so the guitar's output is clean.

Interval
At its most basic, an interval is the difference in pitch between two tones. Intervals are normally measured as the difference between the lower tone and the higher. For instance, the interval between C and G is called a fifth; the interval between strings on a violin, cello, mandolin, etc. is a fifth; the interval between guitar and bass strings, normally, is a fourth.

Intonation
Literally this means pitch, or using pitch. One who speaks with intonation uses pitch variations (presumably to help convey meaning). In our discourse of dealing with music, however, it has taken on a connotative meaning of describing pitch. When we refer to intonation we are often speaking of pitch accuracy or of relating to a pitch being produced. This is just how the word is often used in context. Similarly, intonation can also mean tuning, as in how an instrument is tuned. For example, sometimes a guitarist will say his guitar's "intonation is out." In this context he means that his instrument will not play in tune with itself.

Isolation Booth
Isolation rooms and smaller iso-booths are acoustically sealed areas built into and (hopefully) easily accessible from the main studio area and/or control room. These areas provide improved separation between loud and soft instruments such as guitars and vocals.

Jack
In the domain of signal interconnects a jack is basically the opposite of a plug. It is the receptacle into which a plug is inserted. If you are plugging your guitar into an amp, for example, you will insert the 1/4-inch phone plug at the end of your guitar cord into the jack on your amp. People sometimes get the words jack and plug confused and use them interchangeably so be careful out there.

Loudspeaker
A transducer that converts electrical energy into sound energy, providing the audible sound in equipment such as public address systems, studio monitors, guitar or bass amplifiers, radios, televisions, and home stereos. A standard dynamic loudspeaker consists of a voice coil, a magnet, a diaphragm and a cone. The electrical energy output of a power amplifier is transmitted as voltage over a wire to the voice coil. The current flowing through the voice coil produces an electromagnetic field that reacts with the stationary magnet in the speaker assembly. The voice coil is attached to a diaphragm, which in turn is attached to the cone. The magnetic fluctuations cause the diaphragm and thus the cone to move, moving air and radiating sound. There are other types of loudspeaker technology, the best known being electrostatic speakers. These differ from dynamic loudspeakers in that they consist of a thin sheet of electrically conductive film suspended between two wire screens. A high-voltage charge is applied to the film and it is alternately attracted to one screen and then the other. This creates motion, which again radiates sound. Another type of loudspeaker are servo drive loudspeakers. These employ servo driven motors attached to the speaker cone in place of the magnet/wire assembly. This type of speaker is generally only used in subwoofer applications, and even then only rarely.

Lowpass Filter
A filter specifically designed to remove frequencies above the cutoff frequency, and allow those below to pass unprocessed is called a lowpass filter. The effect of a lowpass filter is to turn down high frequencies. Common examples include the "treble" controls on many lower end radios and stereos, the passive "tone" controls often found on electric guitars and basses, hi-cut filters on consoles, and of course, this type of filter is found on many synthesizers.

Machine Head
On a guitar, or similar instrument, the mechanism found at the headstock that tightens or loosens strings gradually so the string can be tuned accurately. This is achieved by means of a gear mechanism. In open machine heads, the mechanism is exposed. In closed machine heads, the mechanism is enclosed.

MI
Abbreviation for Musical Instrument. MI is a broad term used to describe the musical instrument marketplace in general. Reference is made to "the MI market," or to a specific "MI store." If a store sells band instruments or guitars, for instance, it is an MI store.

MIDI Mode
One of several ways in which a device can respond to incoming MIDI information. There are two parts to each mode, one defining whether it is monophonic or polyphonic, and the other determining if it is multitimbral or not. Four modes are included in the MIDI spec, and two others, Multi Mode and Mono Mode (for MIDI guitar) were developed later.

1. Omni On/Poly - Device responds to MIDI data regardless of channel, and is polyphonic. (See WFTD "Polyphonic")
2. Omni On/Mono - Device responds to MIDI data regardless of channel, and is monophonic. This mode is rarely, if ever, used.
3. Omni Off/Poly - Device responds to MIDI data only on one particular channel, and is polyphonic. This is the normal mode for most keyboards that are not functioning multitimbrally.
4. Omni Off/Mono - Device responds to MIDI data only on one particular channel, and is monophonic.

Miller Effect
This is a cycle of resistance and capacitance occurring between the input and output of an amplifier circuit, which can create a primitive low-pass filter that is signal dependant. The effective input impedance of an amplifier depends on the impedance connected from input to output of the amplifier. The apparent scaling of this impedance often dominates the input impedance and frequency response of the amplifier. This effect was first reported by John Miller in 1919 and is now commonly known as the Miller Effect or Miller Capacitance. The term is often seen when reading about guitar amplifier circuit design. It refers to the effective multiplication of the plate-to-grid capacitance in a triode tube (such as a 12AX7) by the gain of the amplifying stage. The same effect occurs in many solid state designs, but we will focus on tubes in this explanation. A typical triode tube contains a plate, a grid and a cathode. When a tube is amplifying a signal, it has to work against the plate-to-grid capacitance, charging and discharging it as the signal changes. Because the grid is high impedance, and doesn't draw or source any current of its own, the charging current for it must be sourced or drawn through the driving source resistance of the input stage. This forms a low pass filter, with a cutoff frequency determined by the source resistance/impedance of the previous stage and the input capacitance. The Miller capacitance in a triode tube is equal to the plate-to-grid capacitance multiplied by a factor equal to the stage gain plus one.

Mute (musical instrument)
A device that is fitted to an instrument to soften or otherwise alter its tone. This may be an object placed inside the bell of a brass instrument, or on the bridge of an orchestral string instrument. In addition to reducing the volume of instruments, mutes change their timbre by suppressing certain harmonics associated with each instrument's characteristic sound. Mutes came into widespread use in classical music in the 19th century, when romantic composers sought new timbres from the orchestra. On string instruments, the mute is usually a small three-prong rubber or felt implement that attaches to the top of the bridge with one prong between each pair of strings. By restricting the vibration of the strings the mute attenuates higher harmonics, resulting in what most people perceive as a "darker" sound. Many different mutes have been used on brass instruments but they all fit into or onto the bell. The common straight mute, a cone-shaped device that is gently force-fit into the bell, attenuates the fundamental pitch and lower harmonics, creating a metallic, almost nasal sound that can become very piercing at high volumes. French horn players often use their hands in the bell of their instrument to achieve a similar effect. Other types of mute are cup mutes, similar to straight mutes, but with a large lip that forms a cup over the bell, resulting in a rounder, more muffled tone. Bucket mutes cover the entire bell and are filled with cotton or a similar substance, attenuating high harmonics and resulting in a soft, muffled tone. Wah-wah mutes are shaped like bowler hats and are opened and closed over the bell to produce their namesake sound. These were commonly used in 1920s jazz. Plungers (yes, unused rubber toilet plungers) are notable for their ability to produce sounds resembling the human voice. A non-musical example of this was the trombone that created the adults' "voices" in the animated Peanuts cartoons. Jazz trumpeters often use Harmon mutes - bulbous mutes with an adjustable cup on the front that creates a "buzzing" sawtooth-type sound. Miles Davis frequently used a Harmon mute with the cup removed, which resulted in his signature timbre. Woodwind mutes are very uncommon, and in the case of the flute are almost completely unheard of. In rare cases when a clarinet or oboe is muted a handkerchief is usually stuffed up the bell, resulting in a muffled sound. Some bassoonists use mutes to regulate volume of extremely low or high pitches. On guitars, "palm muting" is a technique executed by resting the heel of the picking hand lightly on the strings, close to the bridge to muffle the strings slightly, while simultaneously hitting the strings with the pick. This technique is used primarily on electric guitar, but it can also be useful for acoustic guitars. This technique is different from those for strings and brass in that it also results in a shortening of the notes played as well as altering the timbre.

Neck Through Body
A neck joint that is used exclusively in solid body and semi-solid body guitars. The "neck" is actually an integral part of the guitar's body and extends the entire length of the instrument, from the headstock to the strap button. The earliest electric guitars by Rickenbacker in the 1930s incorporated neck-through designs. Les Paul's early experimental guitars also began with a 4" wood post that ran from tail to headstock, with the sawed-off halves of a guitar body glued onto its sides. More advanced neck-through designs use dovetail joints or dados - a "groove" in one piece that fits a "tab" in the other - to connect the full-length neck to the body wings. A neck through body guitar is often lighter in weight than either a set neck or a bolt-on neck and helps produce a brighter sound than these joints.

Node
The opposite of a anti-node. When standing waves occur, there are positions in space relative to the wave, called nodes, at which there is no movement at all. The wave interferes with itself to create this instance of opposition (e.g., a wave reflecting off of a wall and back into its own path). Nodes are spaced one-half wavelength apart. On either side of a node is a vibrating antinode. The antinodes alternate in the direction of the wave's displacement so that the wave at any instant resembles a graph of a sine wave. On a guitar string the nodes are the places on the string that best produce harmonics - particularly at the 12th fret. Touching the antinodes damps the sound.Also node refers to connection points along a cable. For example, a ribbon cable may have connectors at each end AND in the middle somewhere. These points are often referred to as nodes.

Normal

1. Corresponding to the usual state, not out of the ordinary.
2. Something the inSync team is NOT accused of being (Can't figure that out; we don't think being nocturnal, doing strange things to guitars, lusting ferociously after electronic gear, and living in caves lit only by the blue phosphorescent glow of computer monitors is so strange. Besides, the resident sloths, bats and owls like it...)
3. In patchbays, a normal is an internal connection from the top row of jacks, to the bottom row. Normalling allows connections that are normally in effect to exist without the need for inserting a patch cable in the front of the bay. For example, the stereo outs of a mixer are generally connected to the inputs on a stereo mixdown deck. By connecting the mixer's outputs to the top back row of a normalled patchbay's jacks, and the mixdown deck to the bottom back row, a connection is made internally in the bay, and does not require extra patch cables.

Notation Software
A unique combination of a sequencer, graphic design and word processor that produces printed music. Notation software programs vary in complexity from simple versions for creating "lead sheets" for pop songs to full-featured programs that are capable of visually representing the extreme notation needs of contemporary orchestral and choral scores. It's important to understand the difference between the "staff view" and printing options offered by many sequencers and the output of notation software. Think of a sequencer this way: it is optimized to make your music sound exactly the way you want it to sound. This includes note durations that are exactly what you want them to be, instrument pitches that play in "concert" key, rather than the actual transposition of, say, a saxophone, and intricate rhythms. The staff or score view of most sequencers attempts to notate all of these in the most literal fashion; i.e. that quick brass stab might appear as a 32nd note followed by a string of 32nd rests. Or bass guitar notes appear in the octave in which they sound, rather than transposed up an octave as they normally appear on paper. Further, few sequencer print functions adequately handle special musical instructions such as crescendos, accelerandos, or other performance instructions. Notation programs, on the other hand, are optimized to make your music look the way it should to make sense to musicians reading the parts. It allows you to insert articulations, grace notes, dynamics changes such as "hairpins" that indicate crescendos and decrescendos, and much more. It thinks the way musicians who read music think. The brass stab example above would likely be notated as a quarter note with a dot above its head to tell the players that the note is short. Most notation software also has enhanced lyric-entry capability that allows positioning lyrics under the correct notes, plus special fonts that help distinguish musical instructions about tempo, volume and other matters. Prior to the development of computers and printers with sophisticated graphics capability almost all printed music was hand-copied or engraved. Now notation software is so common that little printed music, other than archival copies of classical music and some jazz and popular "fake books," exist in engraved form. In fact, Warner-Chappell, the world's largest publisher of print music, employs thousands of freelance music copyists with the stipulation that they all use Finale, a common notation program.

Off-Axis
Refers to an audio source that is not directly in front of a transducer, especially a microphone. This results in off-axis coloration; a distortion or change in the frequency response of the reproduced audio signal. Often this coloration is put to good use. For example, many engineers intentionally set up mics on guitar amps so that they are slightly off access to control the amount of high frequencies captured. A microphone will generally produce the "truest" results if it is used on-axis (oriented directly in front of the sound source).

Overdrive
In general, a state of heightened activity or concentration. In mechanics, overdrive is a gearing mechanism of a motor vehicle engine that reduces the power output required to maintain driving speed in a specific range by lowering the gear ratio. In audio, overdrive is generally considered to be another word for distortion or clipping. When you overdrive something with too much level it distorts. For guitarists, however, there is a distinction between overdrive and distortion. In the domain of guitar sounds distortion generally means extreme distortion and is associated with a buzzing or "fuzz" type of sound. To guitarists overdrive represents the guitar equivalent of the general or mechanical definition above. It is a state of (for lack of a better term) semi-distortion. A heightened concentration of harmonic energy and presence, but not the same as all out distortion. Technically it is just distortion, but it's mild enough that more of the character of the guitar comes through.

P90
Refers to Gibson's first successful single coil pickup design, found on many Gibson guitar models originating in the 50's. It is larger than many modern pickups and are commonly found in the "soap bar" design, named so because it has a size and shape similar to a small bar of soap, or the "dog ear" design, which is characterized by a large triangular mounting surface at each end. P90's are known for high output (for a single coil) and biting treble response. Nowadays there are many strengths and styles of "P90" pickups from several manufacturers.

Parameter
Literally a factor that determines a range of variables. In our domain we come across parameters all the time. Any function of any device we can set or modify can be thought of as a parameter. This would include the volume of your guitar amp or the pan position of a channel in your mixer. More specifically, however, the word parameter has been used in things like keyboards, synthesizers, effects processors, and other software driven devices to call attention to specific aspects of any program or patch that can be modified. For example, even on simple non-programmable reverb units quite often the user can adjust the parameter known as Reverb Time. More complex and flexible devices typically have more user adjustable parameters. Some devices over the years have been thought of as too complex because too many parameters have to be understood by the user in order to make anything meaningful happen. This is one reason why in today's sophisticated equipment we rely so much upon the factory presets to get us started and why many users never go beyond them.

Partial
Any one of a series of tones which usually accompany the prime tone (fundamental) produced by a string, an organ-pipe, the human voice, etc. The fundamental is the string tone produced by the vibration of the whole string, or the entire column of air in the pipe; the partial tones are produced by the vibration of fractional parts of that string or air-column. Harmonic tones such as these are also obtained, on any stringed instrument which is stopped (guitar, violin, zither), by lightly touching a nodal point of a string.

Pick Guard
A device applied to the surface of a guitar (or bass, etc.) to protect its finish from scratches that may occur due to picks scraping across the top while playing. Pick guards are usually made from some type of plastic, although metal and other materials are sometimes used. They come in many shapes and sizes, and are an integral part of the overall aesthetic of many instruments.

Pole Piece
A shaped piece of high permeability metal, usually soft iron, which serves to concentrate and direct the magnetic field of a permanent magnet to maximize efficiency of devices like loudspeakers, magnetic cartridges, and cutterheads. Pole pieces are needed because magnets are hard (expensive) to make in the complex shapes that can be needed. In layman's terms, the Pole Piece is the part of the speaker magnet assembly that the voice coil (see WFTD archive voice coil) slips over. It is the center round piece. Guitar and bass pickups work on similar concepts, though the function is the opposite of a loud speaker. Instead a guitar pickup's job is to turn mechanical vibration into electrical output. Magnetic guitar pickups often have individual pole pieces positioned under each string to help maximize or otherwise tailor their output.

Polyphonic
When discussing musical instruments, the ability to play more than one note simultaneously. All instruments have a finite number of notes they can produce at one time. For example, a six string guitar has a maximum of 6-note polyphony. A synthesizer might be 32-note polyphonic, and so on. The more notes of polyphony an instrument can produce, the more capable it is of playing complex arrangements and chords. If the polyphony of the instrument is exceeded, it must "steal" the notes it needs from others that are already sounding. For example, a synthesizer might steal the last note requested from the first one hit; the first note stops, and the new one begins to sound. Some synths and samplers use sophisticated algorithms for voice stealing, others allow you to pre-allocate a given number of voices to a particular MIDI channel, and so on. Compare "polyphonic" to "multitimbral" in the WFTD archive.

Power Chord
In music, a power chord is an interval, which serves the function of a major or minor chord. It consists only of three pitches with one doubled at the octave, separated by a perfect fifth or its inversion the perfect fourth. Power chords are commonly used in various forms of rock music including hard rock, metal, and punk, as the sound of a power chord is not dissonant when distorted, for example by a fuzzbox (distortion pedal) when played on an electric guitar. It is used less commonly in other types of music but became much more common after the rise in popularity of metal during the 1980's. Examples of power chords with C as the root note are C4-F4, C4-G4, C4-F4-C5, and C4-G4-C5 (where the numbers after each note name signify the octave). Most commonly the three-pitch class power chord is played.

Preamp
Short for preamplifier. A type of amplifier specifically designed to amplify very weak signals before they are fed to subsequent gain stages or devices. Preamps are commonly used to bring things like the output of microphones up to a level where more equipment can work with the signal. Similarly, magnetic pickups (as used in guitars and basses), and phonograph cartridges are generally run through a preamp to prepare the signal to be used by other equipment downstream. Preamps are called upon to deliver extremely high amounts of gain while introducing very low amounts of noise and distortion. As such they are a critical component in the audio chain, and in recent years have come under much scrutiny by recording engineers causing many dozens of stand-alone mic preamps to be developed that allege to have superior sonic characteristics.

Re-Amp
The process of running an already recorded signal back through an amplifier (and possibly speakers) of some sort. With the increased popularity and flexibility of DAW systems this has become a popular technique for guitar. An engineer may record the guitar signal dry, or even directly out of the guitar itself along with or instead of any amplifiers, preamps, or effects, and then later process the raw track(s) through a guitar amp or some other preamp or processor. This is accomplished by routing the raw or dry guitar sound (or any other track, for that matter) out of an output of the DAW and into the amp - then out of the amp, usually by way of miking the speaker, back into another channel of the DAW. Sometimes this is also done with plug-ins inside the DAW itself. This final produced sound may then be recorded to another track or simply treated as a live instrument for mixing. This enables artists and engineers the maximum amount of flexibility for the sound as the piece progresses. Often times the guitar sound doesn't get finalized until the mixdown. While this technique is most commonly used for guitar it is also done for bass, keyboards, and sometimes even things like vocals or drums for special effects.

Rectifier
An electronic circuit or component designed to convert AC waveforms into DC. Normally these are used in the power supply of all types of equipment to provide the DC power source required by most electronic components for operation. Any electrical equipment that audio signals pass through possesses a rectifier as part of its power supply. In a sense, what a rectifier does is act as a one way gate where sinusoidal (see sine wave) current (AC) is changed to something closer to constant current (DC). Two types of rectifiers are half-wave and full-wave rectifiers, and are so named because of what they do with the negative portion of the wave. A half-wave rectifier literally lops off the negative portion and only sends along the positive part of the wave. This is basically what a single diode does. A full-wave rectifier takes the negative portion and "folds" it into the positive half, creating something closer to true constant current. Today all modern (including vacuum tube-based) audio equipment uses full-wave rectifiers; they are often a set of diodes in a special configuration located immediately after a power transformer. More modern designs have a single component that acts as a rectifier. Some tube amplifiers still have a tube rectifier as well. Although a rectifier doesn't directly affect the tone or audio quality of a signal, it can still affect the sustain in the case of a tube rectifier because a tube will 'sag' in power output slightly when a power draw occurs (like when you hit a power chord on a guitar or play the amp at a loud volume). As the tube rectifier 'catches up' (so to speak), it will actually slowly reattenuate to its normal power output, which - believe it or not - can elongate the sustain of the note(s) being played.

Remix
Back in the days of analog recording, remix was a producer's term that simply meant; "Ok, this mix sucks, let's do it again (or something along those lines)." Seriously, (prior to its present day meaning) a remix is where a producer takes the original multitrack tape of a commercial piece and remixes a new master recording. The original drums, bass, guitar, keyboards, and vocals all recorded on isolated tracks may be kept or replaced with new performances. With the emergence of digital samplers and drum loops (often called "beats") a form of music became popularized where old classic songs were put to a new rhythm track to make them more "danceable". This is usually what most people mean today when they use the term remix. The Tempo or BPM (Beats Per Minute) can be set at a faster speed. The vocals are then cut up and stretched or compressed to fit the groove. The bass and other instruments may be rerecorded, though snips of the original tracks may be retained to give it authenticity.

Resonator
A metal cone over which the strings of a specially constructed "resophonic" guitar pass. The resonator is sometimes referred to as a "pie pan." Resophonic guitars are designed with 1 or 3 cones, which give the guitar a distinctive metallic twang. The pie pans were originally employed to produce more volume than a wooden soundboard. With the advent of electric amplification volume was no longer an issue. The distinctive tone, often used in country or blues, is the reason to play one of these instruments.

Samarium-Cobalt Magnet
Samarium Cobalt (SmCo5) is used in making a new permanent magnet material and has the highest resistance to demagnetization of any known material. Samarium itself is a rare earth metal, with a bright silver luster. Cobalt is a tough lustrous silver-white magnetic metallic element that is related to and occurs with iron and nickel and is used especially in alloys. Other uses of Samarium include: Carbon-arc lighting for the motion picture industry (together with other rare earth metals), doping CaF2 crystals for use in optical lasers, as a neutron absorber in nuclear reactors. It is also used for headphones, and now guitar pickups. (Recall that guitar pickups are magnetic coils.) Samarium Cobalt Magnets can achieve very strong fields for their size (second to neodymium), which has far reaching implications for transducer design.

Scale Length
In stringed instruments such as guitar, bass, banjo, etc. scale length is the distance from the nut to the bridge or saddle; basically, the total length of the vibrating portion of the string. The scale length is a major determinant for the pitch range of the instrument. For example, a violin has a shorter scale length than a viola. A piano, however, has different scale lengths to make it easier to cover a greater range of pitches. In instruments such as guitar, bass, banjo, etc. string tension increases with scale length. This is because a longer string will tend to vibrate at a lower frequency; therefore it requires more tension to bring it up to a given pitch. There are compromises to be made in either direction so it's not as if shorter or longer scale lengths are "better;" they simply provide different characteristics that may or may not be advantageous to a given player or instrument.A formula is applied to the scale length to determine the fret positions for instruments with frets. This is critical for the correct intonation at various positions. Guitars, basses, etc. may have varying numbers of frets, but they always have a very carefully calculated relationship to scale length. The 12th fret up the fingerboard on most of these instruments plays a note one octave above the open string. It's commonly believed that this 12th fret is at the halfway point along the string, however, pressing the string down onto the fingerboard stretches it and raises the pitch slightly, so the octave fret is usually a bit shy of the halfway point to compensate. A guitar player does use the halfway point of the open string to play a harmonic one octave higher.

Sensitivity
In audio terms, sensitivity is the minimum amount of input signal required to drive a device to its rated output level. Normally, this specification is associated with amplifiers and microphones, but FM tuners, phono cartridges, and most other types of gear have a sensitivity rating as well. In general, higher sensitivity is better (less input signal required for full output), but there are definitely situations where a device can be TOO sensitive (picture a very sensitive microphone in front of a wound-up Marshall guitar amplifier!) resulting in unwanted distortion.

Set Neck
Sometimes referred to as a "set-in neck", a guitar neck that is glued into place on the body of the guitar. Guitar makers have used this method for as long as acoustic guitars have existed; acoustic guitars almost always employ set-neck construction. The neck joint is carefully cut to match its mounting point on the guitar body and the two sections are almost always connected with dove-tail joints to maximize the gluing surface and minimize the possibility of the neck moving. On electric guitars, some builders feel a set-in neck joint gives the guitar a "singing" quality - notes seem to swell after the pick attack until they reach their final amplitude. Smooth, warm sustain with moderate attack are characteristics often attributed to set-in guitars. A classic example of an electric guitar with a set neck is the Gibson Les Paul.

Single Coil
A musical instrument (usually guitar or bass) magnetic pickup design that uses only one coil of wire around a magnet. This is in contrast with a dual coil, or humbucking pickup design. Both designs are common and each has its own strengths and weaknesses.

Slip Mode
An editing mode found in Pro Tools software. Slip mode allows you to place an audio region anywhere you wish, independent of any grid or time code values. This mode is handy for all the other stuff you do in Pro Tools, particularly when it comes to working with regions that don't have any relevance to the musical timing of the piece. Often times vocal and guitar tracks are comped with this mode. If you place a region over another region the first region will be cut off at the point where the new region starts and/or ends. The three other major editing modes in Pro Tools are Spot Mode, Grid Mode and Shuffle Mode.

Solid Body (guitar)
The version of the instrument that is most well known today is the "solid body" electric guitar: a guitar made of solid wood, without resonating airspaces within it. The first solid body electric guitar was designed by musician and inventor Les Paul, working after hours in the Epiphone Guitar factory. His "log" guitar, so called because it consisted of a simple rectangular block of wood with a neck attached to it, is generally considered to be the first solid body electric guitar. Les Paul claims to have developed his first solid body electric guitar as early as 1941.

Speaker Cabinet
A cabinet is the common term for an enclosure in which a loudspeaker is mounted. The major role of the enclosure is to prevent the negative phase sound waves from the rear of the speaker from combining with the positive phase sound waves at the front of the speaker. The result of this would be cancellation and interference patterns, causing the efficiency and sound of the speaker to be compromised. The ideal mount for a loudspeaker is a flat board (baffle) of infinite size with infinite space behind it. Thus the rear sound waves cannot cancel the front sound waves. Given a shortage of infinite size boards, cabinets (enclosures) must use other techniques to maximize the proper output of the loudspeaker. This is called loading. To place the loudspeaker in a large sealed box, filled mostly with foam or wadding, is commonly referred to as an infinite baffle, as it approximates the ideal mount. Following on from this is a smaller sealed box, or, an acoustic suspension enclosure. With the correct loudspeaker, this will improve the efficiency and frequency response of the speaker. Other types of cabinets attempt to improve the low frequency response or overall efficiency of the loudspeaker by using various combinations of reflex ports, transmission lines (material or structure that forms a path from one place to another for directing the transmission of acoustic waves), and horns. For guitar cabinets, which in the early days were little more than a speaker in a wooden box with some insulation, it was the sympathetic vibrations and resonances of the cabinet that helped to give the characteristic sound that many players still rely upon even in more modern equipment.

Squelch
A function found on some radio receiving systems such as wireless microphones and guitar units that allow the user to set the receiver to mute or gate itself when the carrier falls below a specified level. The idea is to eliminate the unwanted noise associated with a radio receiver being tuned between stations, or not properly picking up a station/transmitter to which it is tuned. Typically turning the squelch control "up" makes the receiver have more of a tendency to mute, which means the carrier strength has to be higher in order for it to operate. If the squelch is set too high the audio will mute from time to time, however, if it is set too low you run the risk of getting blasts of noise through the system when the signal strength is compromised for one reason or another. The squelch control was an important part of wireless systems for many years, but with modern technology there are more sophisticated and automated methods of handling these things, which have all but eliminated the manual squelch control from systems.

Stack
In addition to methods and types of amplification, guitar amps also come in different physical configurations. Along with the Combo style, guitar amps also come in separate Head, which refers to the amplifier section and Speaker Cabinets. These allow you to use any amp head with virtually any speaker cabinet. They also break the amp into two units, making each unit lighter and easier to carry than a single combo. Combining two cabinets and a head is called a "stack."

Stoptail Bridge
A Stoptail bridge is a combination of bridge and Stop tailpiece mounted directly to the body of solid body guitar. A Stop tailpiece is a separate bar, mounted on the body behind a movable or fixed bridge that holds the strings. The advantage of a Stoptail bridge is greater tuning stability than a tremolo bar and takes advantage of the resonance of the body of the guitar provided by direct transmission of string vibration. Guitarists and guitar-makers alike believe that a Stoptail Bridge creates a richer tone and better sustain.

Stratitis
1. Stratitis (Strat-itis) is a fairly common but virulent disease amongst guitar players regardless of experience or skill level. At present, there is only one known cure, which has a number of variations, each offering relief dependant on the severity of the individual case. The base cure for Stratitis is for the afflicted guitarist to purchase a Fender Stratocaster (preferably from Sweetwater), which results in an immediate and global reduction of anxiety. In more severe cases, a 50th Anniversary Strat, or a '56 Stratocaster reissue from the Custom shop may be called for in order to provide relief. 2. Stratitis is simultaneous multiple discordant frequency syndrome. To state it non-technically, the sole function of a magnet in a guitar pickup is to magnetize the strings -- any more magnetism than that is unnecessary and detrimental. The excessive magnetism causes different sections of the string to vibrate at different rates producing multiple dissonant frequencies from the same string. The effect becomes even more unpleasant when the string is out of tune. Excessive magnetism is the reason you can't set a typical Fender-style single-coil pickup (Hence Strat-itis) very close to the strings if you want to avoid "Stratitis" and loss of natural sustain. (Buzz and rattles are also caused by excessive magnetism pulling the strings into the frets.) When the magnet is also the core material of the pickup's coil, as in a Fender-style single-coil pickup, the magnetic properties and the core's effect on inductance and Q make the situation even more difficult. It's better to use separate magnetic and core materials so each can be selected precisely for the necessary characteristics.

Tablature
A system of writing music for fretted instruments, most commonly the guitar, whereby a number or letter appears on lines representing the strings, indicating the fret to be played. A six-line staff graphically represents the guitar fingerboard, with the top line indicating the highest sounding string (high E). By placing a number on the appropriate line, the string and fret of any note can be indicated. The number 0 represents an open string. An 'X' means to muffle, not let it ring.

Take
A recorded performance. In music a take could be a band running through a whole song, or a guitarist just overdubbing a solo, or a singer punching in one word. Often times in music production many takes of a performance are made, and the best one is kept. In some cases the best parts of several takes are edited together (comped) to create one ideal composite take.

Transducer
For our purposes, a transducer is an electronic component that transforms one type of energy into another. Some examples: A microphone converts sound into electric current. Likewise, a speaker converts electric current into sound. Other common transducers include magnetic guitar pickups, piezo pickups, phonograph cartridges (remember those?) and tape heads. One of the main challenges we all face (whether we know it or not) is overcoming the physical limitations transducers put on our ability to reproduce the extremely wide dynamic range of acoustic sounds... deadly enemies of your gear!

Transient
A non-repeating waveform, usually of much higher level than the surrounding sounds or average level. Good examples of transients include the attack of many percussion instruments, the "pluck" or attack part of a guitar note, consonants in human speech (i.e. "T"), and so on. Due to their higher-than-average level and fleeting nature, transients are difficult to record and reproduce, eating up precious headroom, and often resulting in overload distortion. Careful use of compression can help tame transients and raise average level, although over-compression will result in a dull, squashed, flat sound to the signal.

Treble
Taken from the Latin triplus, meaning three, treble originally referred to a high singing voice, such as that of a young girl or boy, in three-part harmony. Now it is more commonly used as an audio term that refers to the high frequency portion of an audio signal often defined as ranging from 1 - 3 kHz, up to about 20 kHz. In music notation, the term "Treble clef" is assigned to a staff which primarily displays notes above Middle C. Treble clef is sometimes referred to as the "G" clef; in sheet music the clef sign is an elaborate version of a "G." And if this symbol is drawn correctly, its swirling curve crosses the line that represents the G above Middle C four times. On electric guitars, keyboard instruments and amplifiers, one of two (or three) tone controls for adjusting the balance of frequencies in the output signal.

Truss Rod
A metal bar or rod used to reinforce the neck of a guitar, bass, or other stringed instrument. The tension created by a set of guitar or bass strings tuned up to pitch is several hundred pounds, which over time takes it toll on the relatively small piece of wood making up a neck. The truss rod is inserted inside for reinforcement and to enable adjustments to the bow of the neck to be made. By turning a properly shaped truss rod at different angles inside the cavity of the neck one can force the neck to slightly different shapes, which obviously will change the playability and action of the overall instrument.

Vibrato Tailpiece
A component found on many electric guitars that allows players to produce a vibrato effect - a series of pitch changes, up or down, on notes. Originally conceived as a replacement for a guitarist's subtle finger movement on the frets, this effect can be used for gentle or extreme pitch changes. A common slang term for the vibrato tailpiece and its control arm is "whammy bar." Inventors have been trying to add vibrato to electric guitars since they first appeared on the scene. The Vibrola, a 1935 guitar made by Rickenbacker (invented by Doc Kauffman, who would later become Leo Fender's first partner), was equipped with a motorized vibrato tailpiece that used cams to stretch and loosen the strings. It didn't work very well. Les Paul claims to have experimented with vibrato controls in the 1930s as well. Ultimately, manufacturers generally adopted the practice of replacing the guitar's bridge with a spring-loaded mechanism that can stretch the strings (to raise pitch) or loosen them (to lower pitch). Commonly these changes are made by pushing or pulling on a control arm that hangs below the strings, within easy reach of the guitarist's right hand. Many historians agree that the first commercially successful unit was designed and marketed by Paul Bigsby in the late 1940s. The challenge of changing pitch by stretching and loosening strings lies in getting the strings to return to their normal intonation, or tuning after using the vibrato. A solution was introduced in "floating" vibrato systems, which allow both upward and downward bends and were designed with locking nuts that allow players to "lock" the strings in tune. Important clarification: many guitarists and manufacturers mistakenly refer to "vibrato" - meaning variations in pitch, with "tremolo" -, which means changes in amplitude, or volume. Fender and Floyd Rose both call their vibrato tailpieces "tremolo," while some amplifiers provide an electronic tremolo unit, which guitarists (following Fender's lead) incorrectly call a "vibrato."

Vocal Booth
Typically a part of a recording studio portioned off from the rest and isolated (to some degree) in terms of sound transmission. Vocal booths have typically been used to provide a space to record solo instruments (such as, but not limited to voice) without the recording being compromised by other elements in the studio. An obvious example would be recording a vocalist live while an ensemble is playing. But applications vary widely. Many times a vocal booth (which could more aptly be called an isolation booth) may be used for a guitar or bass cabinet when recording drums and other basic tracks for a song. In other applications a vocal booth may be in or adjacent to a control room and used to record voice overs for video or commercials. In this case there may not be any large studio space at all. In any case vocal booths are typically made out of materials that provide a good deal of sound isolation from outside and provide mostly sound absorption on the inside.

Wireless
A system that is able to transmit data from one point to another without a direct connection, i.e. wires. Typically such systems use some form of RF (Radio Frequency) transm