Why do my computer speakers have some kind of strange sound emitting from them?

Question

so, i will just be sitting here at my pc, and when i get a text message or someone calls my cell phone. my speakers will have all sorts of interference on them. i can literally answer my phone before it rings.And it sometimes just randomly happens and i dont get a call or text message, the speakers just go crazy.

anyways, what causes this? and how can i stop it? does it have a specific name?

p.s. it happens at my dads work as well. thank you

Answer 1

This is very common with GSM based cell phones (ie AT&T in the U.S., most providers in the rest of the world).

These phones periodically emit pulsed data transmissions when the tower is sending information to them. These emissions are fairly strong and the frequencies being used seem to cause some consumer electronics such as computer and car speakers to pick them up. This can be referred to as "electromagnetic interference" or EMI. Basically the strong, pulsed radio waves being used in this case are causing the speaker coils to move and produce the sounds you hear.

The design parameters of most consumer electronics allows them to be susceptible to interference from other transmissions since shielding them from such is rather an expensive endeavor.

There is usually not much you can do, however it usually only means you need to keep the cell phone a few more feet away from the speakers.