JBL 10" Sub Wiring

[rmangoni]

Anybody have any experience with JBL Subwoofer wiring? I have a 2008 2900SE with a factory JBL system. The sub has 12 volt power with a working blue led light confirming power, but the speaker wiring only has 6 volts. I would assume a 12 volt system would have 12 volts at the leads. All fuses are good, no corrosion. I did notice there is 12 volts at the AMP and also 6 volts for at some locations there as well. Not sure if an AMP problem or sub problem, not sure if 6 volts at the speaker leads on the sub is normal? Thanks for any advise.

[jrsick]

Short answer is that if system is working good then you are fine, turn up the volume!
I know a little about audio power setups, not an expert. If your sound system is working properly, then your speakers are probably receiving power from an amp that is bridged. If so, what you are seeing is probably normal. Some questions:
- is your stereo working fine and all speakers/sub producing good volume?
- can you trace back to your amp? Is it bridged?
- did you check negative speaker lead for power? It is 6V also?
- what tool are you using to check voltage, and, what are your using as a ground?
Sorry for all the questions.

[rmangoni]

Hello, first thank you for your reply. To answer your question.
1. System is working fine, good volume on the 6 1/2" & 6x9 speakers
2. it's a single Amp, not sure about bridging
3. Also not sure about 6v negative you asked
4. I'm using a digital meter, grounds seem all good, clean and tight.

I did find the online manual last night. Apparently there is a removable front cover to adjust the gain and other controls which i didn't know where there when I wrote this post and will be checking these controls today, possibly previous owner turned these down to remove the bass sound from the system.

Otherwise rest of system is working fine, just sub is receiving power but no sound/bass even when volume turned up.

[jrsick]

So issue is only with the sub. Likely a power problem. If it is powered by head unit then almost certainly not enough watts to bounce the cone. Knowing source and amount of power to the sub is the key. Even if sub is getting power, it needs at least 100w to make any waves at all.
There are numerous videos for checking sub operation. You could also try taking all freqs above 200hz to lowest levels and see if sub is making sound.