Subwoofer: 2 ohm or 4 ohm

what is the difference between 4 and 2 ohm subwoofer, and which one is better

a 2 ohm speaker is 1/2 the load on an amp that a 4 ohm speaker. The real usefulness is picking speaker(s) that load the amp down as much as possible, to increase the amps output power.

alright, thanks

a 2 ohm speaker is 1/2 the load on an amp that a 4 ohm speaker. The real usefulness is picking speaker(s) that load the amp down as much as possible, to increase the amps output power.
I don't understand.

If an amp is 2ohm stable, and it pushes 500wrms @ 2ohms, it gives ~250wrms at 4ohms, correct?

How would loading the amp with more resistance get more power from it when 1/2 the resistance pulls twice as much power?

a 2 ohm speaker is 1/2 the load on an amp that a 4 ohm speaker. The real usefulness is picking speaker(s) that load the amp down as much as possible, to increase the amps output power.

I think "load the amp down" means lower the resistance.

Less resistance yields more power. Example: a 4 ohm DVC sub can be wired to 2 ohms. A 2 ohm DVC sub can be wired to 1 ohm, wich will receive more power assuming the amp is 1 ohm stable.

I think "load the amp down" means lower the resistance.
...makes sense...

302exploder, these wiring diagrams might be helpful:

http://www.crutchfieldadvisor.com/ISEO-rgbtcspd/learningcenter/car/subwoofers_wiring.html

so let me see if i got this right: the impedence of the sub doesn't have to match the impedence of the amp. so i can have a dual 4 ohm voice coil sub and run it off an amp at 2 ohms? and a sub with higher impedence will pull more power from an amp?

so let me see if i got this right: the impedence of the sub doesn't have to match the impedence of the amp. so i can have a dual 4 ohm voice coil sub and run it off an amp at 2 ohms? and a sub with higher impedence will pull more power from an amp?

Correct, a dual 4 ohm sub wired in parallel can be run off an amp at 2 ohms. However, a higher impedance will pull less power from an amp... a lower impedance will pull more power from an amp.

Take a look at the power ratings on this amp: http://www.drdetailshop.com/d1100d.htm

It does 425 x 1 @ 4 ohms, 800 x 1 @ 2 ohms, and 1100 x 1 @ 1 ohm.

Higher impedance doesnt pull power from the amp. It puts more resistance one the amp causing the amp to push less power to the speaker. Lower impedance (resistance), the more power the amp can produce. Pretty simple.

after looking at my original post ..... I meant to say that a 2 ohm speaker is twice the load, not 1/2. Thanx for catching it.

takes twice to force to reach equal power output in 4ohm than 2ohm.

I was just trying to state that the sub doesnt pull power from the amp The amp puts out power relative to the impandance conected to the amp.

I was just trying to state that the sub doesnt pull power from the amp The amp puts out power relative to the impandance conected to the amp.

Right... I said it wrong.