system
Given the following post, respond as if you're commenting on Reddit:
human
Why do my speakers "toot toot toot" whenever a mobile phone comes near?

I know this has something to do with my speakers picking up the radio signals my phone is sending to the local tower. But why is it only some speakers and not others that behave this way?

Another thing I have noticed:

Whenever my phone is near my speaker, and another mobile phone enters the vicinity, it does the "toot toot toot" sound. For example, sometimes I'll be sitting upstairs (by the speaker) and I'll hear it go "toot toot toot" and I'll know someone is at the door, before they even ring the bell (provided they have a mobile phone). Why does this happen. Is my phone able to detect there is another phone near by?
gpt
Your phone sends and receives electromagnetic signals in the air.  These signals are waves that can interfere with and slightly change the current of electricity going to your speakers and cause it to make the sound.  

On a side note if you want to see something cool put your cellphone underneath an oldskool CRT computer monitor and send it a text message.