(Kadamba Kanana Swami, 29 September 2013, Melbourne, Australia, Srimad Bhagavatam 2.2.36)
Yes, it is! There are devotees who do that. They play a tape very softly. Some even play it too loud when they are sleeping and they are hearing it like that even while sleeping. So yes, if you feel inspired, you can do that – play some kirtan or something, softly in the background.
Personally, I do not like it so much. I am a light sleeper and I do not sleep very well. Even if there is anything softly playing, I wake up all the time so I do not do it. But yes, some devotees are doing it. So that is a choice, as much hearing as possible. So go for it!