I have found plain barrel 16" AR's to be pretty loud In fact seemingly louder than a braked or comped AR. I think this is due to the direction of the sound wave. With a plain barrel it can bounce off objects right back at the shooter. I think Brakes/Comps send it in a different direction and less comes back. This is in environments with things to reflect off of. If you were in the wide open the experience would likely be different. I find the Griffen to be pretty good at blast/concussion and it has a blast shield available.

https://www.griffinarmament.com/M4SD-5-56-Tactical-Compensator-1-2x28-p/xhp556tc.htm

I find it doesn't have the negative push down that the Battlecomp has. I have a Gemtech with blast shield too. I find that it indeed aides when trying to be considerate to fellow shooters. It does seem to counter the brakes effectiveness but when in an environment I need the shield, I don't care.

41 minutes ago, Shane45 said:

I have found plain barrel 16" AR's to be pretty loud In fact seemingly louder than a braked or comped AR. I think this is due to the direction of the sound wave.

I'm with you on this. Part of it may be that the dudes with bare muzzles seem to also always be shooting m193 of m855 type ammo, which is loud. 

However, comps, to a limited extent do some of the same things flash suppressors do in spades. Namely act as a heat sink and diffuse the gas. This takes heat energy out of the gas quicker, and this can often times mean they get a teensy bit less blasty. They then of course usually point that blast some direction other than "thataway" which mitigates the very minimal losses. Some flash suppressors also rob the expanding gas of energy via a tuning fork effect. Which is why you get a way different sounding muzzle blast out of a vortex style flash suppressor. 

 

some brakes are even really really good at suppressing flash without being flash suppressors.