Audio oracle: Speaker buzz mystery

[BillChin]

I bought a used set of Cambridge speakers (2 small speakers and a subwoofer set up) and hooked them up to my piano keyboard. They had an annoying buzz. I have another set of Yamaha speakers (similar satellite 3-speaker system) and they don't buzz. I hooked up the Cambridge speakers to the computer, and there is no buzz. What might be the cause of this? I bought a cheap 3.5 mm male to male patch cable for the Cambridge speakers. The Yamaha uses a similar though nicer cable. Swapping cables didn't solve the problem. For the keyboard I have to use an 1/4" adapter. The Yamaha speakers are fine with the keyboard using the plug adapter.

Is it worth buying and trying a 3.5 mm to 1/4" patch cable? Or perhaps a different adapter plug? The Cambridge speakers have more volume and fuller sound than the Yamaha setup.

[fearfaoin]

Are they powered speakers? If so, these things
are usually grounding problems. If you have a
piece of wire and some wire strippers the easiest
thing to try is to connect a bare end of wire to
a metal screw or some other bare metal on both
the keyboard and the speakers. This should make
them commonly grounded.

If they're plugged into different power outlets,
try using the same outlet, and that can sometimes
help.

[fearfaoin]

You could also try one of these ground loop isolators:
http://www.radioshack.com/product/index ... Id=2062214

[BillChin]

Fearfaoin,

Yes, both sets are powered speakers. Your diagnosis sounds likely, I'll try some of your solutions.

Thank you.

[MTGuru]

If your piano keyboard and/or speaker uses a 3-prong grounded electrical plug, you can try lifting the ground. Just use one of those 3-to-2 prong plug adaptors and don't connect the ground wire. An old stage technician's trick.

Yes, ground loops can be maddening to detect and cure.