Both wifi and bluetooth operate using radio frequencies in MHz region. It is undisputed that these chips create EMI. Put your ear close to any SMPS power supply and you will hear a very high frequency whine. wifi, bluetooth, SMPS, square wave, quasi sine wave circuits in invertors and telivision and computer monitors are the worst offenders. I turn off wifi and bluetooth on each and every device. On my computer, raspberry PI and other devices I disable wifi and bluetooth in the kernel itself. We
audiofools go to great lengths to have the best performance. Some of these practice are
Psychoacoustics and probably require psychiatric treatment.
Few examples whose end effect can be questionable.
1) shielded cables instead of twisted pairs (twisted pairs also do the job). Lately I have converted many of my cables and find they are much better than highly priced commercial cables because the twisted pairs from ethernet cables give very low capacitance.
2) Ethernet instead of wi-fi. This really helps if you are streaming.
3) isolation transformers instead of UPS (sine wave or otherwise)
4) Hi-Res instead of 44.1 kHz (I really can't make out difference but it gives me peace of mind)
5) Linear Power supplies. (I really can't make out difference, but the SMPS power supply by itself do make noise and I can hear with my own ears the high frequency whine). In contrast LPS transformers make a faint 50 Hz noise from the transformer.
Some of us go to extremes (thank my stars I'm not afflicted with the below).
1) cable mysticism
2) Distortion producing amps (valve amps)
3) Power cables costing more than the amp
4) Power conditioners which are nothing more than EMI filters
Many of us (me primarily) will not sleep peacefully in the night with the knowledge that the music room is spewing noise through wifi, bluetooth and SMPS units.
Noise plays a huge role in the way we percieve music. One of the first to realize that our brain alters the way we hear actual music was George Simon Ohm. So every person hears music differently and every person have different tastes. e.g. I just don't seem to like Hindustani or Carnatic classical.
Read this article. It is fascinating.