sync bass with subwoofer

[hmrneves]

Hello, I thing this is the right /r/ to ask this. I have a HTiB and I want to make 2 led strips with ~6 meters blink with bass. I have done some tests with my old subwoofer (logitech z5500) and I noticed that as the bass goes deeper, I got distorsions...

I have read that we can use an amp to store energy (? :S) but it could start a fire due the heat. Can someone help me? Obviously I can use the leds directly conected to the subwoofer and dont turn the subwoofer volume to high and everything will be ok, but I really want to make something cool and safe.
Regards and thanks!

The HTiB this an Onkyo HT-S9700THX, and the subwoofer is powered directly to current, the amp just pass signals. I thing this is called a pre-amp subwoofer, correct if Im wrong please.

 

[americanaudiophile]

You can't just hook leds across the line level input of the sub or the output of the subwoofer amp inside the cabinet. You need circuit like these
http://freecircuitdiagram.com/2008/09/10/led-audio-level-indicator-and-alarm-the-dot-turns-to-bar-when-the-signal-reach-maximum-level/
http://freecircuitdiagram.com/2008/09/17/simple-logarithmic-led-bar-display-using-an6884-ic/