Ohms

prytocorduroy

Can somebody please give me a dumbed down explanation of these, specifically in amplifiers (bass or guitar if there's even a difference)?
Thanks in advance.

Novawind

Ohm is a unit of measurement for electrical resistance. To be scientific, it actually incorporates a real part (the resistance) and the imaginary part (the reactance) and together these form the impedance, also measured in ohms.

For what you need to know, just check the output of your amp and make sure it matches the cab you want to go to. On combos the speaker is already matched to the amplifier. If you have a head, on the back it should specify (4ohm, 8ohm, or 16ohm) and then make sure the cab you're running has the same impedance. The reason is that if your cab has a higher impedance than what your amp is rated, you might not get a good sound out of it (could be muted or garbled). If your cab has a lower impedance than your amp is rated, you could overwork the speakers and potentially blow them at high volumes, and again it could sound garbled.

ianvomsaal

Here you go - read up:
http://www.marktaw.com/recording/Electronics/OhmsAmpsandSpeakers.html

- Ian

prytocorduroy

Novawind wrote:

Ohm is a unit of measurement for electrical resistance. To be scientific, it actually incorporates a real part (the resistance) and the imaginary part (the reactance) and together these form the impedance, also measured in ohms.

For what you need to know, just check the output of your amp and make sure it matches the cab you want to go to. On combos the speaker is already matched to the amplifier. If you have a head, on the back it should specify (4ohm, 8ohm, or 16ohm) and then make sure the cab you're running has the same impedance. The reason is that if your cab has a higher impedance than what your amp is rated, you might not get a good sound out of it (could be muted or garbled). If your cab has a lower impedance than your amp is rated, you could overwork the speakers and potentially blow them at high volumes, and again it could sound garbled.

Okay, thank you! This is much better than all the physics and equations I kept running into online

ianvomsaal wrote:

Here you go - read up:
http://www.marktaw.com/recording/Electronics/OhmsAmpsandSpeakers.html

- Ian

Thank, reading now, looks much easier to comprehend than what I kept running into.

prytocorduroy

Guess I can't escape the math part
Shit.



So let me get this straight then. Let's say I have a 500 watt head at 4 ohms, and I have two 8 ohm cabs (so 16 ohms total) I want to hook up. That would produce 125 watts?

^^^ This is possibly a reality in a few months so that's why I'm giving specific numbers.


Also from what I got, having two 8 ohm cabs will cause more resistance and produce half as many watts?





Fuck my head hurts

ianvomsaal

danny72688 wrote:

Guess I can't escape the math part
Shit.
So let me get this straight then. Let's say I have a 500 watt head at 4 ohms, and I have two 8 ohm cabs (so 16 ohms total) I want to hook up. That would produce 125 watts?

^^^ This is possibly a reality in a few months so that's why I'm giving specific numbers.
Also from what I got, having two 8 ohm cabs will cause more resistance and produce half as many watts?
Fuck my head hurts

Dude, it's easy - if you run two 8-ohm cabinets in Parallel they produce 4-ohms together.
Your 500-watt amp at 4ohm produces 500-watts.
You're running a 4-ohm load so no need for calculations - your amp is 4-ohms, your speakers parallel together create 4-ohms.
The amp and speakers match, so it's just 500-watts . . . DONE.

Now if you're running your speakers in series - your calculations are correct.
Just break out the calculator if you're unsure:
Amp Output= 500watts TIMES
Amp rated at 4ohms DIVIDED BY 16ohms {Speaker-A (8ohm) + Speaker-B (8ohm) = 16ohms} = .25 or 1/4
SO . . . 500 X .25 = 125watts to each speaker.

prytocorduroy

Yeah it's not really that hard, but I'm being lazy about it. Guess that's gotta change quickly