This is a problem I have run into constantly – if my AT&T Palm Treo was within 5 feet of my desktop computer, the speakers would spit out a horrible buzzing, crackling sound. Lifehacker has a potential solution:
Do your speakers buzz and crackle whenever a new text message or call is about to come in on your nearby cell phone? What has come to be known as “GSM Buzz” happens because the wire in poorly shielded speakers acts as an antenna for the frequency the cell phone operates on. Rather than shell out a lot of money for better shielded speakers, you cancel out the speaker buzz with magnets—the tube-shaped ferrite beads commonly found on USB cables. Harvest them from the round block at the end of an old USB cable with a pair of scissors, or just buy a few on the cheap from an electronic supply store. Tape the ferrite bead to the cable of the offending speaker, and the magnet should provide enough passive frequency suppression to do away with the horrible buzzing and popping.
I haven’t tried this yet, but you can bet I will as soon as I get home. Thanks Lifehacker!