Even the best horn bands ie Chicago, TOP have sucky sound production thru the P/A. Go there and listen for yourself. Very disappointing.
Maynard's band was the only one I ever heard that consistently got it right.
The only way I've ever found to make it work so I can always hear myself at least passably is to blow like hell all night. Isn't fun but is my only guarantee I will be heard. In the small clubs this sometimes means that the second player & I actually play louder than the amplified musicians.