Cant get my sub to work on my denon avr2808 and dont think it ever has it doesnt even work on the test signal

Hello Terry, your Denon AVR 2808, is not compatible with HDMI 4K signals, only for HDMI type 1.3, HD signals
You can use your TV to connect all HDMI 4K sources and send a fiber optic connection from the TV to the Denon to get the sound of the equipment connected to the TV
Greetings Franco Dosil

Hola Terry, tu Denon AVR 2808, no es compatible con se?ales HDMI 4K, solamente para se?ales HDMI tipo 1.3, HD
Puedes usar tu TV para conectar todas las fuentes HDMI 4K y envias una conexion de fibra optica desde el TV, hacia el Denon para obtener el sonido de los equipos conectados en el televisor
Saludos Franco Dosil
https://www.denon.es/es/product/hometheater/avreceivers/avr2808 https://www.denon.co.uk/uk/product/hometheater/avreceivers/avr2808 https://ca.denon.com/ca/product/hometheater/receivers/avr2808ci?docname=avr-2808ci-om-e_102.pdf

Sub will only work in surround mode, not stereo mode. Also source must have sub component (5.1, 7.1, 9.1 etc) If your system was transmitting sub signal before, be sure you have chosen a mode which includes a sub signal.

A Denon AVR 889 is not a sub so we don't know anything about the sub in question.

Maybe the existence of the sub is no longer set in the AVR. Look at the speaker definitions first before going to wild.

Try another cable to the sub.

OR, run the sub's signal supply cable to one of the Tape Outs on the receiver and tune in something on FM. If that works a) it will be loud, and b) go back to the SUB settings on the AVR.

Crack the sub open and access the terminals on the speaker itself. Disconnect them from internal components and run one of your amp channels directly to it. If it works, the amp or signal path are dead. If it doesn't work, it's a dead driver.

Is there a switch on the back of the receiver that will switch the sub signal from digital to analog? And the same switch might be on the subwoofer itself.

Hope that helps if not just reply back.
Thanks

Did it ever work? Are you certain the sub is getting a signal. It has to be defined. How about the speaker levels adjustment? Did that work? Give us a clue.

on the am 6 by bose you have to use all the supplied cables or you will blow them. the way it works is that all the speaker signal/power from the denon goes directly to the sub, then the sub sends the signal to each speaker. if you do this correctly the sub takes what it needs and sends the rest to the smaller speakers. and you wont blow them unless you hook them directly to your reciever.

Try using front pre out to the sub from the receiver. the crossover is in the sub anyway. If this works change your settings on the receiver and test again. If sub is still inop, could be an internal issue with the sub amp. Does your sub amp have an on/auto/off switch or light? check that as well. Hope this helps, if you need further assistance, send a reply and I'll help some more

well as long as all signals are routed through the Denon your on the right track, now what else you have to do is connect all devices to the reciever do not loop one device through another. Also you have to try the different surround fields to hear the one you like the best for music I use 5Ch stereo for movies the surround field varies based on the type of movie

Instead of connecting it to the sub output, try it on the L or R output of your amp.
This will eliminate the Denon.
If this fails, you need to test the loudspeaker driver unit whilst disconnected from the sub amp. Use a 1.5v cell (AA or bigger) connect using croc leads to the speaker's terminals. If the speaker is OK, you should hear a click. If you hear nothing, the speaker unit is faulty.

if the subwoofer is on in the reciecer settings then maybe the amp is not getting the signal or the amp is not amplifying
try unplugging the output of the sub then turn off the reciever for a min. then turn it on wait , then plug the sub in
if that don't work then test the sub output with a stereo that has a audio input
also test the subwoofer with a audio output to it( only a positive and a negitive wire for sub)