Subwoofer cutting in and out at high volumes

Jonathan_337 · Postby **Jonathan_337** » January 12th, 2017, 4:21 pm

Hey guys I'm completely stuck. I have a Crossfire C3 501 monoblock rated at 500RMS @ 1ohm. It's stable at 1 ohm.

Previously I had a Kicker Comp VR 12" which was 4 ohm DVC wired at 2 ohms to it, ran fine. No clipping power issues etc. worked fine for about 2 years.

Recently wanted to upgrade to a sealed box Alpine Type S 10" which is DVC 2 ohm to get some more power out of it with a nice clean sound.

The Alpine Sub is cutting at higher volumes even with very very minimal gain, less than the first notch out of 7 and no bass boost. I regrounded it straight on the chassis, grinded off the paint etc. and it's taking slightly more gain now without cutting, but still, almost nothing and it sounds very soft as compared to the kicker which was getting a lot less power.

The head unit is pretty old as well, and the RCAs. I'm not sure if that could cause this problem though. Any suggestions anyone ? Really stumped right now.

Brian Steele · Postby **Brian Steele** » January 12th, 2017, 7:15 pm

Make sure that you've got the DVC coils connected up correctly - if one is connected out of phase, you'll get little or no sound out of the subwoofer.

Jonathan_337 · Postby **Jonathan_337** » January 13th, 2017, 7:59 pm

Brian Steele wrote:Make sure that you've got the DVC coils connected up correctly - if one is connected out of phase, you'll get little or no sound out of the subwoofer.

Yep everything is good. Positive to positive negative to negative.

I used an article I found about setting the gain using a multimeter. Basically your RMS x Ohms and square root of that. So 500x1 and root that, which is 22.36V. Set the gain such that at 3/4 volume, the speaker receives 22.1V.

It reduced a lot but it's not very loud, I'm thinking a sealed box that's pretty small could be causing it to be sounding softer than it could ?

racedriverpro · Postby **racedriverpro** » January 13th, 2017, 8:27 pm

Sounds like a short circuit problem. Check ohms of both coils and make sure ur sub wires not shorting at the amp via sloppy connection to the amp output.

Jonathan_337 · Postby **Jonathan_337** » January 14th, 2017, 10:01 am

racedriverpro wrote:Sounds like a short circuit problem. Check ohms of both coils and make sure ur sub wires not shorting at the amp via sloppy connection to the amp output.

It's DVC 2 ohm and my multimeter shows 3 ohms at each coil, is that normal?

Rovin · Postby **Rovin** » January 14th, 2017, 12:51 pm

try another similar sub with same coil impedance without changing any settings & see if it does d same thing ...

racedriverpro · Postby **racedriverpro** » January 15th, 2017, 9:38 am

Jonathan_337 wrote:
racedriverpro wrote:Sounds like a short circuit problem. Check ohms of both coils and make sure ur sub wires not shorting at the amp via sloppy connection to the amp output.

It's DVC 2 ohm and my multimeter shows 3 ohms at each coil, is that normal?

2 ohms vc usually reads around 1.8 at the terminals, unless it was repaired or actually a 4 ohm dvc. If shorting or burnt u would get a lower reading than spec. Current supply can cause this too. Double check everything.