What causes "cupped hands"?


I've been dealing with this puzzling phenomenon for several months. I can't seem to rid my system of the "cupped hands" or megaphone effect. Acoustic treatments seem to help but haven't diminished it to an acceptable point. I've been told that cables can cause it but haven't been able to confirm this. The system consists of:

Mark Levinson 390S CD Player
Antique Sound Lab KMP-60 Fox DT Amps
Aerial Acoustics 7B Speakers
1.5 Meter ZCable LIVE v4 Interconnects
4' ZCable PASSION v3 Speaker Cables

Any ideas?
skipperrik
Speaker placement can be a major cause. Are your speakers well away from walls and not back in corners? Also could happen if you inadvertently have a backward LE-DE room. I.e. the speaker end of the room is live and the listener end is dead.

will
Cupped hands effect produces sound like when you cup your hands around your mouth to focus your voice....like a megaphone used by a cheerleader. The room I'm listening in is 15' x 35' with the speakers placed 5' out from the 15' wall and 30" in from the side walls. The listening position is 9' from the speakers. The room has a sloping ceiling that rises from 8' at the speaker end to 16' at the opposite end. My cables are pretty short with the ICs being 1.5 meters and the speaker cables only 4 feet long. Acoustic treatment has yielded only marginal improvements, but with a room that big, it could take considerably more than I have. Thanks for your comments so far!
May be non-linear phase response or cable reflections/electrical resonance. This can be caused by cables, particularly long ones. Lossy cables can cause general musical soup as well, particularly in the high-frequencies. This effect was obvious in my system when I immersed some IC's in LNO2 as an experiment. It damaged the surface finish of the wire, I believe. Sounded like the music was coming through a tunnel. The correct way to do this is to lower the temp and raise the temp slowly. It was just an experiment, but yielded useful information.

You can learn more about electrical resonance at he Audio FAQ page of:
http://www.empiricalaudio.com
including the results of the cryo immersion experiment.