Originally Posted by donktard
I was wondering whats Revel (Ultima 2) owners take and experience with acoustic treatments of first reflections? I assume they were built with first reflections in mind (courtesy of Harman Group) so I assume I should minimize treatment unless I find it really beneficial?
I have a media room that is about 16 feet wide and 25 feet long. The room is dedicated to mainly audio. The main stereo speakers (Salon2's) are located about 4 feet from the back16 foot wall, and each is about 3 feet from the side wall. I use 4 inch thick fiberglass absorbers. Each absorber is 2 feet by 4 feet, and sits on the floor. I move them from time-to-time to experiment with the various locations.
The wall behind the speakers has a row of vertical absorbers, that is, lots of absorption. The side walls have no absorbers at the first reflection points. As example of other speakers: I've had the original Salons in the room and I used absorbers with those although they weren't bad without them. I've also used Linkwitz Orions in the room, and didn't use side wall absorbers.
I feel that one of the many good qualities of the Salon2's is that their off axis response is even and slowly falls off with increasing angle off axis. This means that sidewall reflections, given the wall is fairly smooth, have an even frequency response. This even off axis response in the Salon2's is implemented by their four-way design, drivers with basic response that extends past the crossovers so that the crossover defines their response, LR 24dB crossovers, and the tweeter wave guide. Each driver has similar off axis response to its "neighbor" at each crossover. The beryllium tweeter is heaven but that is another subject.
Most loudspeakers have off axis peaks somewhere above the mid-range/tweeter crossover, where the tweeter's dispersion is wider than the mid-range's. When reflected, this excess in response causes a peak in the response in the 2kHz to 5kHz region where the ear is very sensitive. It makes the speaker sound harsh, it makes violins sound painful, etc. It is likely the reason why many people spend years fooling around with magic cable, tubes, swapping amps and loudspeakers, etc. It is also the reason why so many people think there are so many bad recordings. The recordings are OK, their loudspeakers are the problem. To me, one look at the horizontal off axis measurements for a loudspeaker in Stereophile is enough to tell if the speaker is worth even one listen. It is a defining characteristic of a loudspeaker. Off axis response with peaks between 2kHz and 8kHz is unacceptable.
The sound can be absorbed at first reflection points, but then their is less "energy" to the music. First reflection absorption acceptable, and certainly better than harsh sound.