My home theater is evolving and with the application of a new subwoofer, along comes an issue. When viewing programming or movies at low volume, my sub automatically turns off. When a bass-heavy sound is presented, the sub turns on. The sub will also remain on provided there is enough intensity in the lower frequency bandwith. My receiver is a Denon 3803 which did not have this intermmitency issue with my last sub. My speakers are set to "small" and crossover (for sub and receiver) is 80 Hz. Aside from the sub replacement, I should mention that I am running a longer length of cable (2 approx. 30' cables connected by an RCA male to male adapter).

Can it be that the signal is attenuated as it leaves the sub preout of the Denon due to the longer lenth of cables?

The sub can be set to "constant on" but will this reflect on my electric bill?

If I did set the sub to "constant on" can I feed off of the AC outlet on the Denon? There are actually 2 outlets on this receiver which one is currently assigned to a small fan.

I appreciate any feedback.

Try raising the sub output on the Denon and lowering the gain on the sub. This will give a stronger signal to the auto on circuit. If you have left and right low level inputs on the sub, try getting a Y splitter and connect to both inputs. If you have these inputs, the signal will be summed in the sub and provide a stronger signal. If neither of these work, switch it to always on. Several manufacturers have said that On and Standby draw the same current when there is no signal. Makes you wonder why they would bother with a Standby mode.

Do not use the switched outputs on the Denon. They are not rated for the amount of current the sub will draw when operating.

Although others are more qualified here than I to answer your questions, I thought in the spirit of helping I would try. I'm a newb but from what I've learned here and elsewhere for that matter, I would say make sure your trim levels in the receiver are up enough to be sending a strong enough signal to trigger the subs auto-on feature.

As far as plugging your sub into your receiver, I don't believe that would be a good idea, at least I believe the owners manual that came with my Pb-10 suggested I not do that with my sub.

Yea, what Randy said.:)

Thanks for the speedy replies. The sub output on the Denon is maxed at +15dB and the sub cable splits to both sub inputs.

Just leave it on all the time. The Auto-On/Off doesn't actually turn the amp off either.

Thank-you-kindly.