Yes it is a very bad idea. Why? In a word, induction.
Every signal in every wire produces a field around that wire. Also when these fields cross a wire they induce a current in the wire. This is how transformers work. This is also how power is generated in everything from hydroelectric dams to phono cartridges. This is also one way RFI gets into systems.
So around every power cord and interconnect is a field that varies up and down with whatever signal is in that wire. With AC its a steady 60 Hz but with music its all over the place. Either way these signals interact with any nearby wire. The result is noise. But hardly ever noise loud enough to be obvious. Instead what happens is the music signal is smeared a little and the background is gray instead of black.
This is all highly relative. Its surprising how much of this there is even in systems that seem dead quiet and clean. Like I said you don't hear it till its gone.
Every signal in every wire produces a field around that wire. Also when these fields cross a wire they induce a current in the wire. This is how transformers work. This is also how power is generated in everything from hydroelectric dams to phono cartridges. This is also one way RFI gets into systems.
So around every power cord and interconnect is a field that varies up and down with whatever signal is in that wire. With AC its a steady 60 Hz but with music its all over the place. Either way these signals interact with any nearby wire. The result is noise. But hardly ever noise loud enough to be obvious. Instead what happens is the music signal is smeared a little and the background is gray instead of black.
This is all highly relative. Its surprising how much of this there is even in systems that seem dead quiet and clean. Like I said you don't hear it till its gone.