people who are saying "if vinyl or CD, then yes this makes a difference, otherwise no": you're missing something...
all these devices depend on master clocks to reproduce your holy "bit perfect" media, like metronomes or the conductor in an orchestra. in the WiiMs they are quartz crystal oscillators (XO).
quartz crystals in all of these "steady state" devices are actually mechanical resonators. If the oscillator is subjected to physical vibration (from transformers, fans, footfalls, or the speakers themselves), the crystal can “pick up” this vibration, modulating its frequency slightly. (microphonics) this can translate into smearing or harshness in the sound.