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how does ohms work?

maskedman72

can someone explain this whole ohms thing?
what does it do to your power?
how do you get your amp to put out the most volume while makeing it work the least.
i have heard of people re-wiring their cabinets to run at different ohms.
please explain
October 23, 2002 @02:38am
David Klausner

Ohms are the units that impedance is measured with. You can kind of think of impedance as the measure of how hard the amp has to push to get current to flow. The lower the impedance, the more power will be output from your amp. Unfortunately, the amplifier circuit wants to push against something, so that if the impedance is too low, the amp can perform badly, and even overheat and burn out. Because of that, you want to pay pretty strict attention to how your amp is rated. Some PA power amps can work from a range of 16 ohms down to 2 ohms, but most guitar amps have a much more restricted range. When you run speakers in series - from one speaker to the next - you are adding their impedances together, so if you connect two 4 ohm cabinets that way, you will have an 8 ohm load. If the speakers are wired in parallel - splitting the signal with a "Y" connector, for example, the formula is 1/x + 1/y = 1/z, where x is the impedance of one speaker, y is the impedance of another, and z is the total impedance. Two 4 ohm cabinets wired this way present a total load of 2 ohms, which is a much louder way to wire them, but will probably do serious damage to a guitar amp.
October 24, 2002 @09:31pm
kornodar37

I'll sort of clear this up, from an actual engineering perspective. There are, in electronics, two quantities that are specified in ohms: impedance... resistance... Both, of course, are specified in ohms.
Ohms, simply stated, is a resistance to the flow of electricity. It has nothing to do with volume, only the amount of "resistance" to the current that flows. The larger the ohm value, i.e. 16 ohms versus 8 ohms, the more resistance is offered.
There are two other values in the electricity equation... voltage - which is the potential for current flow. Just because voltage exists doesn't mean that current is flowing (i.e. similar to a battery sitting in a drawer). Current is the second... this is "real work" in electrical circuits. Current ONLY flows when a circuit is completed and voltage is present. The AMOUNT of current that flows is directly related to the amount of resistance. Less resistance = more current...
Current, voltage and resistance are all related: V=I*R... Higher voltage implies a greater capacity for more current, etc.
There is, virtually, no difference in volume between a 4 OHM, 8 OHM and 16 OHM setup IF, IF, IF, the amp is setup to handle each of those instances. Speaker volume (loudness) is a direct response to input voltage/current and a function of its sensitivity NOT impedence.
The impedance (4 OHM, 8 OHM and 16 OHM) is the resistance the amplifier (power amp) has to overcome to produce sound energy. Amps are designed to run "efficiently" at one impedance or another. Obviously, if an amp provides the same voltage, no matter what, a larger impedance MAY mean lower drive current to the speakers. As speakers are primarily current driven devices, an 8 OHM amp driving 16 OHMS MAY be "softer" but ONLY due to the fact that the current flowing in the speaker/amp circuit is halved.
Conversely, an 8 OHM amp driving a 4 OHM load MAY be louder but that's due to the fact that the amp/speaker circuit has twice the current (the ability to do real work) flowing. This impedance mis-match MAY destroy your power amp. MORE CURRENT FLOWING = MORE POWER REQUIRED. LOWER IMPEDANCE = GREATER POWER REQUIREMENTS. Amps spec'd at 8 ohms, running 4 OHM loads have to dissipate more power in the amp... if it's not made to do that it can destroy the amp...
SUMMARY
Impedance/resistance, is specified in ohms. It refers to how much resistance is offered to the flow of electricity in a circuit. The larger the ohm value, the more resistance is offered. The lower the less. Lower impedances = more current flow and more power required. Higher impedances = less current flow and less power required. Loudness levels are dependant upon speaker sensitivity, not current draw in an amp.
November 28, 2002 @04:03pm
kornodar37

I'll sort of clear this up, from an actual engineering perspective. There are, in electronics, two quantities that are specified in ohms: impedance... resistance... Both, of course, are specified in ohms.
Ohms, simply stated, is a resistance to the flow of electricity. It has nothing to do with volume, only the amount of "resistance" to the current that flows. The larger the ohm value, i.e. 16 ohms versus 8 ohms, the more resistance is offered.
There are two other values in the electricity equation... voltage - which is the potential for current flow. Just because voltage exists doesn't mean that current is flowing (i.e. similar to a battery sitting in a drawer). Current is the second... this is "real work" in electrical circuits. Current ONLY flows when a circuit is completed and voltage is present. The AMOUNT of current that flows is directly related to the amount of resistance. Less resistance = more current...
Current, voltage and resistance are all related: V=I*R... Higher voltage implies a greater capacity for more current, etc.
There is, virtually, no difference in volume between a 4 OHM, 8 OHM and 16 OHM setup IF, IF, IF, the amp is setup to handle each of those instances. Speaker volume (loudness) is a direct response to input voltage/current and a function of its sensitivity NOT impedence.
The impedance (4 OHM, 8 OHM and 16 OHM) is the resistance the amplifier (power amp) has to overcome to produce sound energy. Amps are designed to run "efficiently" at one impedance or another. Obviously, if an amp provides the same voltage, no matter what, a larger impedance MAY mean lower drive current to the speakers. As speakers are primarily current driven devices, an 8 OHM amp driving 16 OHMS MAY be "softer" but ONLY due to the fact that the current flowing in the speaker/amp circuit is halved.
Conversely, an 8 OHM amp driving a 4 OHM load MAY be louder but that's due to the fact that the amp/speaker circuit has twice the current (the ability to do real work) flowing. This impedance mis-match MAY destroy your power amp. MORE CURRENT FLOWING = MORE POWER REQUIRED. LOWER IMPEDANCE = GREATER POWER REQUIREMENTS. Amps spec'd at 8 ohms, running 4 OHM loads have to dissipate more power in the amp... if it's not made to do that it can destroy the amp...
SUMMARY
Impedance/resistance, is specified in ohms. It refers to how much resistance is offered to the flow of electricity in a circuit. The larger the ohm value, the more resistance is offered. The lower the less. Lower impedances = more current flow and more power required. Higher impedances = less current flow and less power required. Loudness levels are dependant upon speaker sensitivity, not current draw in an amp.
November 29, 2002 @01:30pm
kornodar37

I'll sort of clear this up, from an actual engineering perspective. There are, in electronics, two quantities that are specified in ohms: impedance... resistance... Both, of course, are specified in ohms.
Ohms, simply stated, is a resistance to the flow of electricity. It has nothing to do with volume, only the amount of "resistance" to the current that flows. The larger the ohm value, i.e. 16 ohms versus 8 ohms, the more resistance is offered.
There are two other values in the electricity equation... voltage - which is the potential for current flow. Just because voltage exists doesn't mean that current is flowing (i.e. similar to a battery sitting in a drawer). Current is the second... this is "real work" in electrical circuits. Current ONLY flows when a circuit is completed and voltage is present. The AMOUNT of current that flows is directly related to the amount of resistance. Less resistance = more current...
Current, voltage and resistance are all related: V=I*R... Higher voltage implies a greater capacity for more current, etc.
There is, virtually, no difference in volume between a 4 OHM, 8 OHM and 16 OHM setup IF, IF, IF, the amp is setup to handle each of those instances. Speaker volume (loudness) is a direct response to input voltage/current and a function of its sensitivity NOT impedence.
The impedance (4 OHM, 8 OHM and 16 OHM) is the resistance the amplifier (power amp) has to overcome to produce sound energy. Amps are designed to run "efficiently" at one impedance or another. Obviously, if an amp provides the same voltage, no matter what, a larger impedance MAY mean lower drive current to the speakers. As speakers are primarily current driven devices, an 8 OHM amp driving 16 OHMS MAY be "softer" but ONLY due to the fact that the current flowing in the speaker/amp circuit is halved.
Conversely, an 8 OHM amp driving a 4 OHM load MAY be louder but that's due to the fact that the amp/speaker circuit has twice the current (the ability to do real work) flowing. This impedance mis-match MAY destroy your power amp. MORE CURRENT FLOWING = MORE POWER REQUIRED. LOWER IMPEDANCE = GREATER POWER REQUIREMENTS. Amps spec'd at 8 ohms, running 4 OHM loads have to dissipate more power in the amp... if it's not made to do that it can destroy the amp...
SUMMARY
Impedance/resistance, is specified in ohms. It refers to how much resistance is offered to the flow of electricity in a circuit. The larger the ohm value, the more resistance is offered. The lower the less. Lower impedances = more current flow and more power required. Higher impedances = less current flow and less power required. Loudness levels are dependant upon speaker sensitivity, not current draw in an amp.
November 29, 2002 @08:36pm