4ohm or 2 ohm sub on a JL 500/1?

[lukemc11]

I have a JL 500/1, most likely getting another (got the first one cheaper than it would to get a 1000/1). It runs 500rms to 1ohm, 2 ohm, and 4 ohm. I was curious to if I would get more power on a 4 ohm sub, or a 2 ohm sub, or would there be any difference what so ever. I am new to car audio, but I noticed most amps don't have high RMS in 4 ohms. I would probably be running 2 S12L74's.

[curtis73]

Running the sub at a lower resistance will increase the output of the amp. Amps are often rated for a resistance at which they are stable. If you have an amp that is 2-ohm stable, run the sub(s) in such a manner that you're providing 2 ohms. More resistance is safe and actually easier on the amp, but won't maximize the combo.

If you run too little resistance, think of it as letting too much electricity flow through the amp and it will fry.

[SupraGuy]

Originally posted by lukemc11
I have a JL 500/1, most likely getting another (got the first one cheaper than it would to get a 1000/1). It runs 500rms to 1ohm, 2 ohm, and 4 ohm.

According to the spec sheet at JL's website the amp provides 500W RMS at anything from 1.5 to 4 ohms impedance, with the sensitivity adjusted to the target woofer's impedance. This means that there is zero benefit to using a lower impedance driver.

Now consider this: Into lower impedance loads, amplifiers typically have lower (worse) S/N ratios, higher (worse) THD, and lower (You guessed it, worse) damping factor.

Take a look at page 11 of the Owner's manual and you'll see the specifications. Note that the THD, S/N ratio, and damping factor are all rated at 4 ohms? That would be because this gives the best results. (Also because JL observes industry standards of rating at 4 ohms.)

All things being considered, you will get the most out of this amplifier by running a 4 ohm subwoofer setup to it.

For other amplifiers, you may be able to get more by running lower impedance loads, however, more power isn't everything. Remember that the lower impedance comes at the price of THD, S/N ratio etc. You'll get more power, but at lower quality. If you want a SQ setup, then you're better off getting the more powerful amplifier, or just living with less power. (That 500/1 has more power than my entire system, but I feel that I have enough.)

[lukemc11]

Thank you for your help. I understand a little better now ; it's getting there