How exactly do ohms work?
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Race Director
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From: My own state of mind
How exactly do ohms work?
So my amp says that it will run at 40W RMS at 4 ohms. Does that mean that if I buy a speaker that says "4 ohms" on the back that it will only give it 40 watts? Someone once told me that to run at two ohms you have to run wire from speaker to speaker and then to an amp or something like that. I know this might be a bit of a newbie question in audio but I just want to make sure that I'm not putting too much power to my brand new front speakers I bought.
Thanks,
Matt
Thanks,
Matt
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Re: How exactly do ohms work? (Golden80)
Melting Slicks
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From: Atlanta GA
Re: How exactly do ohms work? (GTLocke13)
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Re: How exactly do ohms work? (Golden80)
Your speaker's impedance should match the load your amp is designed for. If your amp is rated at 40x2 @ 4-ohms then you should be using 4-ohm speakers.
Some amps can handle a bigger load (lower resistance). For example an amp maybe stable down to a 2-ohm load. This is typical with high quality stereo amps and high quality mono-block amps. An amp like this will usually be rated at a higher power level at the lower impendence. For example a mon-block amp may be 250x1 @ 4-ohms and 500x1 @ 2-ohms. If this is the case you obviously want to run the amp at the lower impedance. A lower impedance load does have a tendency to distort a bit more, but in the case of a mono-block sub amp this usually will not be detectable.
To get a 2-ohm load you could take one 4-ohm DVC sub and run the two coils in parallel.
You could also connect a pair of single voice coil 4-ohm subs to the amp in parallel.
And lastly you could take a pair of 2-ohm DVC subs and wire the DVCs in series (bringing each driver up to 4-ohms) and then wire both drivers to the amp in parallel.
Some amps can handle a bigger load (lower resistance). For example an amp maybe stable down to a 2-ohm load. This is typical with high quality stereo amps and high quality mono-block amps. An amp like this will usually be rated at a higher power level at the lower impendence. For example a mon-block amp may be 250x1 @ 4-ohms and 500x1 @ 2-ohms. If this is the case you obviously want to run the amp at the lower impedance. A lower impedance load does have a tendency to distort a bit more, but in the case of a mono-block sub amp this usually will not be detectable.
To get a 2-ohm load you could take one 4-ohm DVC sub and run the two coils in parallel.
You could also connect a pair of single voice coil 4-ohm subs to the amp in parallel.
And lastly you could take a pair of 2-ohm DVC subs and wire the DVCs in series (bringing each driver up to 4-ohms) and then wire both drivers to the amp in parallel.
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Re: How exactly do ohms work? (rbartick)
I guess I was curious because my amp paperwork had specs for the wattage's at different ohms. So if my specs say 40W x 4 at 4 ohms then my front speakers that handle 40W RMS are not at risk of blowing out?
Matt
Matt
Melting Slicks
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From: Atlanta GA
Re: How exactly do ohms work? (Tonycino)
I guess I was curious because my amp paperwork had specs for the wattage's at different ohms. So if my specs say 40W x 4 at 4 ohms then my front speakers that handle 40W RMS are not at risk of blowing out?
Matt
Matt
Racer
Joined: Oct 2002
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From: Newark, DE
Re: How exactly do ohms work? (leolufse)
I guess I was curious because my amp paperwork had specs for the wattage's at different ohms. So if my specs say 40W x 4 at 4 ohms then my front speakers that handle 40W RMS are not at risk of blowing out?
Matt
correct.
Matt
correct.
Wrong. That 40W rating on those speakers is a THERMAL POWER RATING. That's how much power it can take before you damage the voice coil by overheating it. You can damage the speaker cone with less power than that. If you hear the speaker distorting, you're giving it too much power, turn it down. The amp is a good match for the speakers, though, because you don't want to run the amp at the ragged edge either.
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