I was doing some testing with one of my M3 last night and I connected Bitmain APW3++ to M3 and power on 2 hashing boards with it.
And it was just what I expected, the miner runs really quiet, only thing that makes loud noise is original M3 PSU.
With Bitmains PSU miner loudness is something like L3+, which is way quieter than S9.
At aprox 12 degrees celsius fans run at approx 3000rpm but the sound is so smooth, no swirling sound like on S9.
With 2 hashing boards connected current consumption is 1400w (230v) and hash rate is approx 7,5-8Ths
So later I will connect one more server PSU 1kw that I have spare and connect the last hashing board.
I will leave this one at home (since it is really quiet now) and see how it behaves and take original PSU to collocation to power some other miners.
I expect a bit more RPM but since the miner likes to run its chips at around 80 degrees celsius it shouldnt change much. But like I said, it has really smooth air flow, so i dont think sound will change a lot even if I get bit more RPM.

I was wondering if it will work since APW doesnt have that strange 3pin connector (like fan) that connects to controller board but it runs just fine without it.
So for all of you guys that dont have collocation you can silence the miner this way.