Audio Systems: No sound from subwoofer


Question
I have an Energy Power 10 subwoofer and can't get any sound to come out of it. The speaker itself doesn't appear to be blown (I tapped the terminals with a battery and it moved). When the sub is on auto mode and I plug in my phone and turn on some music the red light turns green, so I assume it's getting a signal. But no sound whatsoever comes out, not even the thump I believe I should hear when I turn the subwoofer on.

Answer
Nice to hear from Finland!  One of my favorite places in the world.

Since this is a powered sub (amplifier built into the box) the best check is to feed a signal directly into the low level audio inputs to check for acoustic signal coming out of the 10' driver.  This will check the amplifier portion of the system.

The high level inputs connect directly to the speaker terminals through the low pass network inside and I think you have already verified the continuity of the dc circuit of the voice coil inside the speaker driver unit.

If you have the box open allowing you to get inside you can check the connections from the output of the audio power amplifier to the driver speaker.  

The fact the pilot lamp goes green when audio is fed into the low level inputs is a sign the auto detection circuit is working; but that does not verify the power amplifier section.

So, my guess is, but it is only a guess, the power output stage of the audio amplifier has failed and may need repair.

Therefore, after checking the items suggested above, let me know the outcome and I can take another look at the problem.

Cheers to Finland  (I like Helsinki; nice city).