Expert: Cleggsan - 7/21/2009

Question
I just put a new kenwood amp 1800 watts class D mone and its pushing two 12 black Mamba 2x4 ohms.. when i turn my bass nob up a little bit the bass hits and then it cuts off and comes back.. I have the speakers wired up going (+,+,-,-) on each sub then + and - going to the amp.. what i'm i doing wrong.

Answer
You may have an impedance mismatch between the amp and speakers.

If your speakers are dual voice coils and you have them in parallel your impedance loading on the amp is only "one" ohm.  That is a terrible stress, almost a short circuit, connected to the amp and it may be going into protection mode.

Try connecting the two voice coils of each speaker in parallel, but put the two speakers in series with one another. This will put a 4 ohm load on the amp which is much less severe.

Crutchfield has diagrams on how to hook up the speakers here:

http://www.crutchfield.com/S-Gg6YbAHxvn6/learn/learningcenter/car/subwoofers_wir...

and try this configuration:

http://www.crutchfield.com/S-Gg6YbAHxvn6/learn/learningcenter/car/subwoofers_wir...

Finally, it is possible one of the voice coils in one of the speakers has shorted out or that you have a short in the speaker lines somewhere.  Check that out as well.

Hope this solves the matter.

C