MK Sub woofer to Denon AVR

The amplifier for the sub has failed.

check that wire and fuse again and try to reset and try

check the box for air leaks, or rubber surround deterioraton.

Hi,
Your sub-woofer apparently does not have an amplifier built into it. This type requires you to use your front left and front right speaker output to got through it to your regular speakers. It is called a passive sub-woofer for that reason.
To set it up, Connect your front speakers to the "output" of the sub. It should say "to speakers" on it.
Then connect the Speaker Outputs for the left front and right front on your Denon AVR-391 directly to the Sub. It should say on the back of the Sub "to amplifier".
Here is some theory you should know, if you don't already know it, that will help you get a satisfactory result in setting up this system.
There is a condition on setting up all speakers and subs that not everyone know. It's call "phase alignment". Phase alignment (A Good Thing) refers to all of the speakers in a system moving in the same direction (in and out) at the same instant in time. This gives you much clearer sound and better response from your sub-woofer.
Phase Cancellation (a bad thing) is when some of the speakers are moving out and other moving in during the very same instant in time. It causes problems in sound.
IN A SUB-WOOFER, IT CAN CANCEL OUT THE LOW NOTES.
Here is how to handle it:
On the back of the receiver the speaker terminal outputs are colored Red and Black. Black is considered negative and Red is considered positive. On the back of the Sub woofer and on the speakers the same colors apply. MAKE SURE THAT ALL OF THE CONNECTIONS GO BLACK TO BLACK AND RED TO RED WHEN CONNECTING UP THE SPEAKER WIRES.
The system will work either way. But you will have severe bass loss if the woofer wiring is out of phase because of phase cancellation.
Hope this helps,
Best Regards,
Mark


"Phase Cancellation"

In the setup menu on your denon receiver make sure the subwoofer setting is set to ON or YES.

you can do this one of two ways, you can use just the left "mono" on your sub or use a y connector. If the sub doesn't show the left as mono then YES you need a y cable

The spkrs sound like they are bi-amp spkrs, meaning you have multiple terminals on the backs of each spkr, the jumpers on the spkrs should be connected as such. Now you just connect the spkrs according to the Denon spkr conection diagram. Do not use the surround back unless you have 6 or 7 pair of spkrs

in the Denon setup under speaker configuration set the sub to LFE+Main

Other listening modes (dolby, dts, neo6) are decoded from digital signals.

Direct will relay your only your discrete analog inputs - so if you want to use your AVR as an amplifier for those channels, you'll need to supply an input signal in a different manner.

:)

Denon AVR-810 was a quite out-dated model. I had owned since 1992. It shown 'Protection' on the screen for 2 months ago and not yet been fixed. Better to replace a modern one or repair it at a reasonable costs.