ID12v3 x JL XD700/5 low output issues

[neo_styles]

Perhaps. Just make sure you inspect the amp before you wire another sub to it. If anything in the amp got damaged as a result of this, you could blow a second subwoofer.

[zako]

Ok I found some of the problem...
Need to turn off the HU amplifier if you are going to get anything from the preouts. So I do this and read 0.7 VAC out the RCAs of my HU. Ok great.

Now that ~0.7 V goes through to the subwoofer speaker outs on my amp with 0 gain.
Now I turn everything down (HU, aux input from FreqGen on iPhone, amp gain)... wire up my sub.
Turn it on, slowly increase volume, and I got nothing. Turned up the HU volume, iPhone volume to full, made sure I was still on Aux input. Gain on amp is 0 at this time. Slowly turn up amp while reading with DMM... Go all the way to 10 VAC, nothing.

I beep checked my RCAs, beep checked the whole signal path all the way to the dual voice coils. Everything is cool.

Now I got a problem.. lol

edit: also flipped between 2 4 and 6 ch settings on amp. Also made sure LPF wasn't cutting out the 50 Hz signal.

IMHO, this and some of your previous posts are consistent with my theory that your subwoofer is bad. You get higher voltage on the amplifier channel as you increase gain. This seems to imply that your RCA cable probably works fine, as well as the amp. Try to hook up a different subwoofer to the amplifier channel or hook this subwoofer to a different amplifier or different channel on the same amplifier (I'd rather not without having verified that this subwoofer will not short and destroy the amplifier.. this seems like a good case to put a fuse on the subwoofer speaker wire.)