I'm not talking about a sound reflector. I mostly mean big bands and concert bands. I have found that when I play in a rock band and I use my in ear monitors, I find it easy to play in tune. In big bands and concert bands where I can't hear myself well, I find playing in tune much more difficult.
Is there some kind of tiny mic/amp/ear bud thing that would do this? If not, somebody needs to invent one. Should bring good money.