New subwoofer humming

[tribz]

Just added a subwoofer to my system and it does nothing but hum. Cant seem to get any audio out if it all.

My receiver is a Denon 1513 and the woofer is yamaha YST-FSW050 and everythings connected as per this.

With the sub lead disconnected theres no hum so I dont think the woofer is faulty, it just hums as soon as its connected to the denon. I've removed all the cables in the back of the denon and the hum remains, however when I unplug the HDMI out the hum then raises its pitch to a higher level.

Everythings plugged into one strip but I've tried moving things onto their own sockets.

Does this sound like a ground loop problem (over hdmi??) or a setting on the denon. Note, I'm clueless with the settings but the speakers are all set as Small and the subwoofer is set to on with LFE+Main in its settings at 120Hz. I've tried playing with these settings to no avail.

Thanks!

 

[lucid]

It may be a ground loop hum, but before you go shooting off down that road do some basic fault finding.

It's not clear from the angle of the picture, but it looks like you have connected up correctly: Subwoofer out on the AVR-1513 to the socket marked Input on the Yam sub. Is that correct?

Are you using the supplied sub cable? If so, is there about 4.5 metres surplus of the stuff coiled up sitting with all the mains cables behind your rack? If so that's a nice little induction loop just waiting to pick up mains hum from nearby power leads.... Try a shorter cable, or if you don't have an old gash lead you can use then at least as an experiment try uncoiling the lead and lay out the surplus on the living room floor away from any power leads.

Also try the sub away from the amp.

Is the sub plugged in to a different wall socket than the rest of the gear? If so, try it in the same extension block as the amp.

Once you have eliminated cabling issues then you can start to look to see if gear is faulty or it's a set-up or configuration issue. If the amp isn't set right for the sub (i.e. no signal) then I'd expect the sub to be quiet. You might hear a faint hiss or very low level hum but nothing more. Report back on the stuff above when you have had chance to try things.

 

[valve90210]

Just added a subwoofer to my system and it does nothing but hum.

Maybe it doesn't know the words...

Ahem..anyway, as has been said above, checking out cabling and mains sockets etc would be the way forward I would say.

Also worth checking the gain settings, could be that they are set too high and it's amplifying any electrical noise...

 

[tribz]

It may be a ground loop hum, but before you go shooting off down that road do some basic fault finding.

It's not clear from the angle of the picture, but it looks like you have connected up correctly: Subwoofer out on the AVR-1513 to the socket marked Input on the Yam sub. Is that correct?

Are you using the supplied sub cable? If so, is there about 4.5 metres surplus of the stuff coiled up sitting with all the mains cables behind your rack? If so that's a nice little induction loop just waiting to pick up mains hum from nearby power leads.... Try a shorter cable, or if you don't have an old gash lead you can use then at least as an experiment try uncoiling the lead and lay out the surplus on the living room floor away from any power leads.

Also try the sub away from the amp.

Is the sub plugged in to a different wall socket than the rest of the gear? If so, try it in the same extension block as the amp.

Once you have eliminated cabling issues then you can start to look to see if gear is faulty or it's a set-up or configuration issue. If the amp isn't set right for the sub (i.e. no signal) then I'd expect the sub to be quiet. You might hear a faint hiss or very low level hum but nothing more. Report back on the stuff above when you have had chance to try things.

Hi Lucid,

Thanks for the advise above. I've tried 3 cables now, the supplied really long one, a composite one and also a digital co-axle one and it still hums. I've tried just having the receiver and the amp on and plugged into the double wall socket. I've also tried them in the power strip, just them on their own. I've also plugged the amp into the other side of the room and then ran the long sub cable to it across the centre of the room as per below ...

http://www.youtube.com/watch?v=OI2ijb86BpA&feature=youtu.be

The hum can be heard as soon as you turn the volume dial and it gets to about half way where its really loud.

I've also tried a Ground Loop Isolator and that reduced the hum it was still very loud.

The speaker test on the denon has nothing coming through the sub but the other speakers are fine.

 

[tribz]

Maybe it doesn't know the words...

Ahem..anyway, as has been said above, checking out cabling and mains sockets etc would be the way forward I would say.

Also worth checking the gain settings, could be that they are set too high and it's amplifying any electrical noise...

Badum, tish!

Where would the gain setting be? I've been through all the onscreen settings in the denon receiver and I cant seem to find anything that makes any difference.

 

[tribz]

Tried my iPhone into the sub via an adaptor and that played fine with no hum

Tried an RCA speaker in the denon sub socket and got diddly on the speaker tone test through it.

Daft question time, does it matter that there's no rears plugged in, just a right left and centre?