Car Stereos: amp/sub problems, kenwood amp, rca cables

Question
Hi, ive asked a few questions already. but i have a problem.
i just bought a type r alpine 12 in sub (1242d), and a kenwood amp (kac-9104d) the light on the amp is on, but nothing is coming out of the sub.
when i first put it in, it worked, and i moved it and it stopped. i dont know what i did.

what could be wrong? and what can i do?


Answer
Hi Nemo,

If the amp is turning on, but no sound is coming from the sub, then it comes down to one of three things: either no audio signal is getting into the amp, no audio signal is coming out of the amp, or the subwoofer itself has a problem.

It's possible that the RCA cables came out partly when you moved the components, so I'd check those first.  Make sure they're plugged into the correct RCAs on the amplifier, and plugged in all the way.  Then make sure the speaker wires are securely attached to the amplifier, and to the subwoofer box.  Next, you might need to pull the sub out of the box, and make sure the wires are still connected there.

For any other troubleshooting, you really need a multimeter with an AC volts setting.  In a case like this, a cheap analog multimeter (with a needle instead of a digital display) actually works best.  While the music is playing, you can set the meter for AC volts and put it on the speaker terminals at the amplifier.  You should be able to see the needle move along with the music.  (If you just have a digital multimeter, you'll just see numbers, but you should be able to tell if the amp is producing any output).  If you're getting power out of the amp's speaker terminals, but the sub isn't playing, then the problem is definitely with the subwoofer.  If you're not getting any power out of the speaker terminals, then the problem must be with the amplifier, or the RCA outputs or RCA cables from the head unit.

Hope this helps!

Brian