I want to do some basic room acoustic measurements specifically, slapback echo in a gym (speakers mounted front of house, 13' up, 50 ft apart), bouncing off back wall 71 feet away. (room is 106' wide) Sound is good on the floor, but when you're on stage you hear the slapback too much. Setting up drapes or sound absorption/diffusion panels on back wall now. Should make the room much better with that in place I want to do some before & after snapshots, to measure treatment effectiveness and target the problem frequencies/modes - it's mostly in midrange area. I've read of one method doing the same frequency sweep in different locations with a DB meter to map a frequency response chart. Anything with a percussive midrange (hand claps, rim shots) is most noticable (Michael Jackson's Streetwalker is a good example) Since I'm tuning the room for the PA, I would play the program source (similar handclaps) through the PA, record it with a flat mic, and see the bounce. Yes, can eq to minimize that, but don't want to change the great sound on the floor. Want to get the best natural sound with room treatment first. Curious if anyone else has a process (sample wavs they want to share? :^) ) and favorite programs (WinXP) that are useful for this. Cheers Apollo: Know thyself. Jamsession: Know thy room. THEN turn knobs.