Sometimes audiophile types like to turn of anything that isnt to do with sound, in case there is any interference. Fluorescent displays in particular can cause electrical noise and a hifi nut (or someone who doesnt want to see the display) can turn it off.
With careful measurement
Sometimes audiophile types like to turn of anything that isnt to do with sound, in case there is any interference. Fluorescent displays in particular can cause electrical noise and a hifi nut (or someone who doesnt want to see the display) can turn it off.