Acoustic panels - how high?

Regardless of a speaker system's dispersion pattern, sound waves travel in a straight line and their angle of reflection will equal their angle of incidence. Thus, an easy way to find the first reflection point, of the waves that will actually reach your ears, is via the method mentioned by Elwood. (http://hyperphysics.phy-astr.gsu.edu/hbase/sound/reflec.html) Yes- a panel that will disperse or absorb those reflections must be chosen.

Further info, here: (http://realtraps.com/rfz.htm) & (http://www.gikacoustics.com/video-early-first-reflection-points/)

Thanks, good info. I have treated first and second reflection points on side walls and improved things quite a bit. Think I will now experiment with a panel on my ceiling. No mention anywhere about treating the front wall either directly between or behind the speakers. Any thoughts?

It all depends on the geometry and the physics. In reality the second reflection points can be worse than the first ones. It all depends on the radiation pattern of the speakers, the dispersion pattern. That's why attention to the placement must be done by ear not some generalized instructions. Otherwise you're only finding the local maximum. Same goes for Tube Traps, you will not find the optimum locations by following the instructions of just plopping them down in the room corners since it depends on where the standing waves are actually located which might easily be two feet from the corner! Hel-looo!

OK, so I've just finished playing - yet again...

A friends place has a 12ft ceiling, so I've been looking at possible solutions.

So I got to thinking about my room with an 8ft ceiling and how a "baffle curtain" might help.

I just happened to have a piece of heavy duty vinyl 2 ft x 6ft and a couple of lighting stands, so I rigged it such that the vinyl hung down from the ceiling like a banner, across the room and tried it in a couple of positions...

1. just behind the speakers...
- There was some improvements in clarity and image
- nothing really to write home about

2. just behind the listening position...
- talk about an OMG moment!
- clarity improved beyond my expectations
- image now easily exceeds the boundaries of the room on most all tracks
- projection of venue acoustics forward now easily envelopes the listener on many tracks
- it's like surround sound with only two speakers
- the improvements can easily be heard outside of the room also, just amazing.

BTW - I also have a couple of 15" x 78"(tall) panels on the side walls behind the speakers to deal with an echo that travelled across that wall behind the speakers

Regards...