nevillebartos

finally about to get my system finished off but need a bit of help choosing a sub, i've read the alpine 8" type R suits the stock enclosure quite well but not sure on the difference between the 2 and 4OHM versions?

Alpine SWR-823D Type-R 8" subwoofer with dual 2-ohm voice coils at Crutchfield.com
Alpine SWR-843D Type-R 8" subwoofer with dual 4-ohm voice coils at Crutchfield.com

if anyone has any recommendations on other subs that will go ok in the stock box let me know!! i intend to power the system with the PDX V9

Alpine PDX-V9 5-channel car amplifier — 100 watts RMS x 4 + 500 watts RMS x 1 at Crutchfield.com

TJM12

If you want the full 500 watts of power from that amp you need the 2 ohm sub setup. 2ohms equals less resistance to the amp therefore allowing more power. Although that might over power the 8inch sub?

nevillebartos

so the 4ohm would reduce the risk of overpowering?

White-JKU

Not true. I'm 99% sure for this amp that it supplies the same rms and peak for 2 and 4 ohms. I have the pdx-m12 powering 2 12 kicker L7 and it puts out 1200rms at both 2 and 4 ohms. It's unusual but alpine is a fantastic company especially for amps. I was skeptical of the same rms for the two ohms but damn does my system hit. Also alpine amps are small enough to fit in a lot of places. As far as 2 vs 4 ohms 4 usually sound better but it isn't to the point where you would notice. I've had both. Go 4 ohm get that amp and some good speakers. You will be happy.

Ryan0260

Go with the 2 ohm speaker, and get an amp that delivers the speakers max power at a 2 ohm load, that way you don't have to worry about overpowering the speaker

TJM12

Ok your right, I went back and looked at the specs on that amp and it does appear to make 500 watts rms from the sub channel with either 2 or 4 ohms which is unusual? Most amps power will increase, in some cases double with lower impedances.

TJM12

For the sub I would still go 2ohms (dual 4ohm) that way if you ever should change amps you'll have generally more power from your amps to that speaker and sub bass is power hungry. Stay up around the high side to just higher than the rms power handling of the subwoofer.

EsByrd

If u go by this u run the risk of damaging ur amp. Rule of thumb is never under power ur sub and never run a amp at full power. I worked car audio a long time and have one many DB competitions. If a sub can handle 500rms then a 750rms amp turn to 65-70% is a good setup and also sounds better do to the fact that a class d amp running above 80% cause distortion.

TJM12

500 watts rms should be ok for that sub as long as you adjust the gain properly and don't push the sub to very high volume levels. It is rated to handle 350 watts rms so your definitely on the high side. The key though is adjusting the gain so your not amplifying distortion. Distortion kills speakers!

White-JKU

Alpine amps are also usually under rated. They can handle and do more than they say. Truthfully you will never be able to tell the difference. 2ohm are easier to run so just do that then. Good choices on the amp. Cant speak for the subs, have only ran kicker.