hum/buzz from subwoofer

[admin_exported]

Dear All

I set up Boston Acoustics Soundware XS system with Onkyo TX-Nr609 a week ago, and have started noticing a hum from the sub-woofer. Is it faulty? or am I doing something wrong?

Please advice, thaks in advance

 

[Andrew Everard]

May be an earth loop, may be some interference being picked up on the subwoofer cable.

Things to try:

- Turn down the gain control on the sub, and boost up the subwoofer channel output on the receiver to compensate. If the hum is being picked up on the cable, this will increase the signal to noise and make the hum a lot less obvious.

- Try moving the subwoofer cable and see whether that reduces the hum. If the sub cable runs alongside other signal cables or mains cables, it can pick up hum – moving it away may make all the difference.

- Try a different subwoofer cable, preferably one with better shielding.

If none of that helps, it may be that the hum is being picked up on one of the signal cables going into the Onkyo. That would tend to be noticable by the hum being louder on one particular source/input, but that isn't always the case. The only way to track this is to disconnect all your source components and the Tv from the receiver, see whether that cures the hum, and then connect them again one by one until the hum returns. It's a pain to do – I know, I've done it one more systems than I care to remember – but you'll usually get to the root of the problem this way.

Hope all this helps...

 

[Anonymous]

I had a similar problem. My amp has 2 line level outputs so I bought a "Y" splitter to combine both signals into one cable input to the sub. Made a dreadful racket and took me ages to suss out. As Andrew says its a step by step process of elimination, pen and piece of paper is useful to record what you've done by the way.

 

[Anonymous]

Thanks Andrew, and thanks nick

Looks like i am going to have a busy time ahead.. will let you know how I get along....

So far I have figured out that hum disappears once I disconnect it from and amp and place it elsewhere in the room

 

[Andrew Everard]

So far I have figured out that hum disappears once I disconnect it from and amp and place it elsewhere in the room

Well, you've ruled out the sub having an internal hum, which might suggest a problem within. The prime suspect would, I think, be the subwoofer cable – it could be faulty, or could just be picking up electrical noise due to the way it's routed.

 

[Anonymous]

Hey Andrew,

Have tried placing the subwoofer at 3-4 different positions in the room but it does tend to pick up the hum after sometime, have ordered a QED performance cable, let see...