eliash
Senior Member
Ttimer quoted this and added:
This is my opinion:
First, the room might NOT be an acoustic nightmare. Does it have slap-echo? If so, then yes it's an acoustic nightmare, but one that can be solved.
When you walk from room to room talking out loud and listening to the timbre of your voice, is it particularly awful in that room? If so, then maybe it is an acoustic nightmare which needs professional help.
However if neither of the above situations apply, it is POSSIBLE that the speaker's off-axis response is causing the acoustic nightmare. Let me give an example: Suppose the speaker is a 6" two-way with a 1" dome tweeter, crossed over at 2 kHz ballpark. Below the crossover frequency, the midwoofer is starting to beam. But above the crossover frequency the tweeter's radiation pattern is extremely wide, like virtually full power at 90 degrees off-axis. An all of this excess off-axis energy is right smack in the region where the ear is most sensitive, 2-4 kHz or so. The net result can include harshness and listening fatigue. It may seem like the room is to blame, when it's really the speaker's off-axis response. Unfortunately it is very difficult to selectively absorb the bottom end of the tweeter's range with room treatments. Presumably there are professionals who know how, but I don't.
But now back to what to do if the room really IS an acoustic nightmare (aside from investing in headphones!):
Imo what you want to do is, have the direct sound from the speakers dominate over the reflected sound. This can be done with very directional speakers, with nearfield listening, or both. If you opt for nearfield or both, you might want to consider speakers with a coaxial mid/tweet driver, so that you can listen from very close without hearing a vertical discontinuity. For nearfield listening that KEF R3 speaker Amir reviewed looks very promising to me. It uses a dedicated woofer in addition to the coaxial unit, which imo is a major advantage over the coaxial-only LS50, in addition to the fine performance Amir's measurements indicate.
If you do not want to listen nearfield, then highly directional main speakers aimed at the sweet spot would imo be a good strategy. If you want a sweet spot wide enough for two or three people, and if using horn or waveguide speakers, you might try using extreme toe-in such that the speakers' axes criss-cross in front of the center of the sweet spot. Note that "highly directional" can include dipole speakers, though some placement restrictions apply. The Sanders Sound Model 10 is imo a very good single-listener speaker.
You mentioned the Gradients - imo they are excellent speakers for problematic rooms. While they are not what I'd call "narrow pattern", their off-axis response tracks their on-axis response very well. So whether the room reflects back a little or a lot, chances are it'll be spectrally correct. If the room is really bad and skews the spectral balance of the reflections (like if it was damped with a bunch of inexpensive foam squares) then the Gradients can't fix that, but ime they are considerably more room-friendly than most. I was a Gradient dealer for many years and only stopped because I wanted to concentrate on my own designs.
“A speaker that has controlled dispersion does basically the same thing you'd expect an acoustic panel to do, but it does a better job. And it allows you to get away with no panels on the wall." - Matt Poes, acoustical consultant (in other words, Matt makes money off of acoustic panel installations, NOT off of speaker sales)
Interesting statement regarding a "speaker's off-axis response is causing the acoustic nightmare".
It seems that such effect could be the reason for my perceived severe harsh sound in exactly that frequency range (around 3KHz and upwards), before installing absorbers in the short, opposite wall and (tilted) ceiling acoustical (i.e. optical) mirror points, apparently reducing this harshness to an acceptable level.
- The question open to me is still why these "short" wall reflections may be the reason to cause a harsh and "taxing" sound perception - what effect could it be, is it neurophysiology or after all simply physically related?
Harsh sound perception did agonize me for quite some time, explanations welcome...