My first day of teaching a synth class (at college or at Sweetwater U) always begins with this analogy: “Imagine that you were the only witness to a crime that happened in a dark alley and that the only clue to solving that crime was an unusual sound you heard. You’re taken to the local police station and asked to describe this unique sound. What are all the generic things that you can say about the sound you heard?”
The answers that I get from the class usually include the following:
- If the sound was high-, medium-, or low-pitched
- How loud the sound was
- If the sound was bright or dark sounding
- How many sounds were happening at once
- If the sound faded in
- If the sound was percussive
- How long the sound lasted
- If it faded out over time or stayed on fully
- If it wiggled in any way
- What direction it came from
- If there was any reverb or echo
Once those responses are written on the blackboard, I then tell the class that a synthesizer is basically a musical tool that gives you individual control over each of those sonic qualities.
Subtractive Synthesis
To keep everything simple, I’m mostly going to talk about the most common type of synthesis, called subtractive synthesis. This method starts with having more sound than you want and then cutting away at it until (hopefully) it sounds like what you were striving for. The analogy I use is: When Michelangelo (sculptor in the early 1500s) was asked how he created his beautiful marble statues, he stated, “I saw the angel in the marble and carved until I set him free.”
Instead of the metal sculpting tools Michelangelo had, a subtractive synthesizer has
- Oscillators
- Mixers
- Filters
- Amps
- Envelopes
- LFOs
- Effects
And then, to control these sonic tools, it often has a keyboard, pitch-bend and modulation wheels, ribbons, pedals, footswitches, and a lot of buttons, knobs, and sliders.
Robert Plant of Led Zeppelin sang: “Yes, there are two paths you can go by . . .” In the synthesizer universe, those two paths are the audio path (the things you can actually hear) and the control path (the things that wiggle and modify the things you can hear). The audio path contains the oscillators, mixers, filters, amps, and effects. The control path contains the LFOs and envelopes along with the keyboard, wheels, knobs, sliders, and switches.
Audio Path Components
We’ll start with the oscillators. The easiest way to think of them is that they’re just wigglers. They wiggle electricity back and forth fast enough that, when they get to your speakers or headphones, you hear them as sound. Typically, the sound coming directly from an oscillator is brighter than you might want and definitely lasts longer than you might want. (On analog synthesizers, the oscillators are always going, even if you’re not playing any notes.) You can choose from a list of basic oscillator waveshapes (sine, triangle, saw, square, pulse) or noise (white noise, pink noise). Often, you can have more than one oscillator per note.
These oscillators are then combined via a mixer to be a single sound source. This sound then goes to one or more filters to help reduce (or remove) any high-frequency or low-frequency sounds that aren’t part of your sonic vision.
After the filtering, the sound goes to an amp (amplifier), which can make the sound louder, softer, or even silent. The final result is then sometimes sent to effects (distortion, chorus, echo, reverb, EQ). These are all part of the audio path.
Control Path Components
Listening to the audio path by itself can quickly become tedious because it won’t have any of the motions and inflections that come from the control path. A keyboard will allow you to control the oscillator’s pitch depending on which keys you press. LFOs (low-frequency oscillators) can add repetitive motion to the oscillator’s pitch (vibrato), the filter’s high cut (wah-wah), and the amp’s loudness (tremolo). Envelopes allow you to create a one-shot shape that can control your filter to make a sound start bright and then get darker over time. An envelope can also be used to change an amp’s loudness over time, which will cause the difference between the sharp attack and quick fade of a marimba and the slow attack and long fade of a string ensemble. You can even use envelopes to change the pitch of the oscillators to sound like cheesy disco toms or space lasers (pew-pew-pew).
Then, when you get the sound close to the way you want it, you can store all your settings in a preset location that you can name, such as “Space Laser.” Going back to that preset will recall all the settings you previously made for that sound.
Those of you who already use synthesizers will think, “Sure, but there’s so much more to it than that.” And, of course, you’d be right. But this is a reasonably concise way to explain how a synthesizer works. Still, none of this matters if you don’t get yourself a synthesizer to try by yourself. It’s not even important if you start with a large or small synth or even if it’s a hardware synth or a virtual synth that’s a computer app. The key thing is to get something and start tweaking parameters. You will be pleased and surprised by how quickly you’ll start having opinions on how your presets should sound.
Synth Clips Videos
You can also build your skills and confidence by watching my free synthesis video tutorials called Synth Clips. There are currently over 30 Synth Clips videos available. Check out all of them by clicking here.
Finally, as always, you can rely on your Sweetwater Sales Engineer at (800) 222-4700 to help you pick out a synthesizer (hardware or virtual), along with the required accessories, to create a synthesizer tool kit that’s exactly right for your musical needs.