Audio Systems: subs, 4 ohms, two subs

Question
I have two 12 inch insignia subs with an amp, model number IS-PCSS101. When i reach a certain volume on
my deck, it will turn off my subs. They are running on a kenwood deck thats a 44x4 high power aplifier. How can i keep it from doing this? Also the
subs are under a back seat in a chevy crew cab truck, space is limited so the boxes have to be
small. I think this is affecting the sound. Is there anything i can do to help this? How big should the boxes be? thank you


Answer
The design of the enclosure is very, very important for optimum performance of bass drivers. If not properly acoustically loaded they will not produce the deep bass notes.

The most common causes of amplifier dropping out are:

1.  Impedance not matched properly (too low; for example, if the two subs are connected in parallel and and each are 4 ohms you would now have a 2 ohm load - and if the amp was rated for 4 ohms it would be loaded with a load too low in impedance).

2.  The power amp is not strong enough.  (Subs like to see whopper amps - a few hundred watts. Yours is anemic but not terrible.  Further , subs like to be driven by separate power amps, not head unit amps)

3.  Shorts in the speaker line (insulation rubbing against the chassis, etc.)  Check the wiring.

4.  Speaker with shorted voice coil placing severe load on the amp.

5.  Pushing them too hard.  As above, it takes oodles of power to drive subs.  You may be overdriving them, causing the amp to overheat, and still not getting much acoustic power out - especially if they are not properly enclosed.

You can online search for sub boxes, but for pickup trucks it becomes a real problem getting enough space for a realistic woofer performance.  Bazooka subs in a tube are popular in trucks because the can fit down in back much easier than rectangular type enclosure.

Hope this will help.


C