You can't get a brake/compensator to be effective without it increasing the noise level. It's like saying I want a 1000 horse power car, but want 30 mpg also. So, pick what variable is more important, and go that route. If I am shooting/hunting with a naked barrel or braked rifle, I will ALWAYS wear hearing protection, which I highly recommend doing before shooting in hunting situations. But I hunt suppressed, so it's always quieter.
The be an effective compensator, it will need to be vented on top. All the compensators I've seen were also vented on the side like a traditional muzzle brake, since this will also help reduce felt recoil and minimize muzzle rise to be able to control the weapon better.