Is the sub output on the receiver turned on. If the receiver is set for full range speakers there will be no output on the LFE channel.

I'd say check any fuses, though I wouldn't think you'd have a light on the sub, but it's worth a try. The other culprit could be simply be a loose wire from the subs internal amp to the driver, or something like that. That's easy to check if you just remove the driver cone (carefully of course, and visually inspect internal wiring. Make sure the power is off of course.

I would bet the answer is in the owners manual for the Denon. You say you hooked up a DVD player and now it dosn't work. I bet there are separate bass managment settings for different inputs.

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I would bet the answer is in the owners manual for the Denon. You say you hooked up a DVD player and now it dosn't work. I bet there are separate bass managment settings for different inputs.

If the original poster using the multi-channel inputs this is most likely the correct answer.

I the DVD player hooked up digitally or analog? If analog how many cables?

I have the solution to your problem.

The sub8 is currently set to lay dormant then activate when louder sounds come on and will remain on to fill in the lower end for a brief time, but will cut off and become dormant again until the next bass heavy scene begins. This of course is a design flaw, but behind the face plate of the amp itself hides the solution.The fix requires no special tools or knowledge of electronics, and if you can use a can opener, are able to tie your own shoes then your problems with this sub can be easily resolved. I suggest the use of a phillips screw driver instead of a drill, or other electronic tool. First, unplug the sub8 from your receiver and power outlet.

Step 1 - Unscrew the four small screws that attach the face plate of the amp to the box. Yes, there are tons of screws on the back of this, but these small screws are located closest to the four corners of the face plate (don't get intimidated, look at it and use your noggin). There is only one SMALL screw per corner of the face plate.

Step 2 - Remove the face plate with a pair of pliers, gripping one of the heat sinks (one of the metal lines that stick out). Pull outward (you may have to alternate pulling at each end of heat sink). NOTE: behind the face plate is a wire attached to the smaller circuit board, so observe the location where it is attached in case you need to reattach it.

Step 3 - Locate the larger circuit board and observe the writing in white lettering. Hold the entire thing so that you can easily read the side with the words. The top row towards the center you should see the word 'Off', underneath that you should read the word 'Auto', then underneath that you should read the word 'On'.

Step 4 - Next to each word are tiny prongs. There is a small dark plastic piece called a 'jumper' attached to the prongs next to the word 'Auto' (the word 'Off' & 'On' do not have a jumper attached to their prongs). The jumper easily comes off, and you want to take it off by pulling it out, then attach it to the prongs next to the word 'On'.

Step 5 - Reattach the face plate to the back of the sub box using the four small screws.

Step 6 - Reconnect sub to receiver and power cord.

Now the sub will switch on when your receiver does every time instead of remaining off until some loud sound activates it.