I try to play a fan sound, thanks to /playsound, at specific coordinates.
To loop this sound, I made a repeater clock.
But the problem is this method isn't that good.
Indeed, when the sound restarts, there is like a "pop" sound at each restart, which is pretty annoying. Then it takes up a lot of space.
This is probably not the most efficient way but you can use a bunch of redstone repeaters and hopper timers to equal the length of the sound and then loop it around to reactivate the command block.
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That is what I used to do until now. But I'm just looking for a better way.