Nighttime music help

[Nightmusichelp]

My ds only sleeps through the night (coming up on 6...) with a particular melody (a peaceful soundtrack from his favourite game) playing on a continuous cycle. I'm having to stream it from youtube onto the ancient TV in his room using an old chrome cast. Can anyone think of a better way of doing this which doesn't involve a large TV screen being on all night? The WiFi also cuts out in his room and extenders haven't helped. I can't download the track from YouTube without paying for a subscription. I'm sure there's a way but my tired brain isn't working. We have an old smartphone whose WiFi doesn't reach to that room, and kids kindles. Happy to buy something but prefer to avoid subscriptions.

Honestly, I'd tell him "the machine" is broken and help him learn to sleep without the music.
What's going to happen when he starts having sleepovers, or you're in a hotel or whatever?

Tape recorder - record it onto a cassette.

@KnickerlessParsons He's only started this week so that seems a bit harsh. He had health problems as a baby and co slept for a very very long time.

If he's only been doing it for a week, I'd nip it in the bud then. You're making a rod for your own back otherwise.
Try reading him a story until he falls asleep instead, or I used to sing to my girls.