Wim Blees certainly got the most for the money if his $500 worth of carpet, wooden strips, and screws solved the problem. That's about what I would expect an acoustical engineer to have charged for a one-time evaluation. Charging $10,000 for an evaluation, in my opinion, is way out of line. After all, this is a recital hall, not the Cathedral of St. John the Divine in New York City with its 200 x 600 ft. nave, and dome high enough to accommodate the Statue of Liberty. Carpet will work wonders for damping out the high frequencies, but it will do little for the mid-range, and nothing for the low frequencies. In Wim's case, it seems that damping the high-end frequencies was sufficient to solve the problem. I mentioned the commercially available panels to inform those facing similar problems that all sorts of options are available to them. For those who have had any experience in this area, common sense will tell you what you need to do. Hard, flat, parallel side-walls, and hard curved rear walls that bring reflected sound to a focus up in the seating area are killers. This is so obvious, and yet it happens all the time because too many architects seem to know nothing about acoustics. Jim Ellis
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