Absorption at the back wall emphasizes the weakness of stereo even more. Spaciousness means reflections from other locations than the direct sound. This is problematic in the frontal half of the room and it is even more severe in the back half if there's absorption. That's why typical LEDE control rooms are live at the back wall and absorptive at the front.
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There's plenty of reflections in my listening room without a "live" back wall (mine's not completely "dead" either, but the reflective areas are mostly diffusive). Between the diffusive front wall, the side walls, the floor and the ceiling the sound bounces around just fine . . . there's no "stereo image" to enhance behind me.
Aha. That description of your room is different from what you've said earlier. If I read "absorptive back wall" then I have to assume just that, an absorptive back wall
I found that some low level surround addition for large hall rendition (when it is on the recording to start with..) can work ok and enhance realism, but I agree, it has to come from more than two sources, and very late, >50ms. Still experimenting.
LEV is enhanced by late reflections but the sensation of spaciousness is caused by (lateral) reflections that have a specific level-time relation. You can "activate" even a 2ms reflection for added spaciousness if it's loud enough.
Yes, I did, but maybe I should explain. When I cut foam for the waveguides it generates a lot of scrap. I started storing this scrap behind the screen in my HT. I also store uncut blocks of the foam back there as well. Over the years this has gotten pretty big, in kind of a pile. It may be just under 4 feet at the base (not exactly sure), but only about 1 foot at the top and doesn't quite go all the way from floor to ceiling. This much foam, if you had to buy it for this purpose, would cost thousands. For me its just scrap.
In most listening spaces the reverberation is dominantly from behind you and not the stage or front of the venue. This is why I believe the absorption needs to be at the front with no absorption at the rear. Toole also recommends this.
How can you say that? Even Toole says that the wall behind the speakers should be damped and I believe that as well. "Not ... many people I know"!
obviously as a dipole user I know that. I sometimes want both, and glad I can control the first. I toe in just enough so not to get too strong a side effect, 20-30 deg is about right.
So the foam isn't covering the whole front wall. Didn't you say that you don't absorb the ceiling reflection but deflect it back to the front wall?
This might be the reason why your configuration sounds spacious: the deflected ceiling reflection bouncing back to the listening position, delayed and decorrelated.
It covers the lower 2/3's or more, so most of it is extremely dead. There might be a small patch at the top that is still reflective, but not much. I doubt very much that much energy from the ceiling gets reflected back to the listener off that wall. The spaciousness comes from the fact that the rest of the room has very hard reflective walls, floor and ceiling, just like I have been saying.
Oh my goodness I really must disagree. Have you ever used a high quality room correction system along with room treatments, and then done an analysis of the results? It can be very eye opening. I can tell you how consistent the results are from room to room. Using these three tools, I was able to get pretty close to identical results in two greatly different size rooms.
I am having a hard time with you saying the knowledge is missing to create meaningful standards, and yet SMPTE and THX have and it works. Are you saying your are far more intelligent than the engineers that are members of SMPTE? So what do we do, nothing? Sorry Markus, I am just not buying it at all.
So are you going to advance the argument that 164 studios poor choices represent the hundreds of thousands of studio all over the world? That would be a stretch on steroids.
You chose a poor example I am afraid, because it is not representative of the current state of the art. That measurement tells me there are all kinds of reflections dogging this speakers frequency response, and that is not representative of how we do things in my field(whether music or movies). Mixing console based monitors are out, stand mounted monitors are in. No tuning or calibration is out, and computer based room modeling, auto room correction and post analysis is in.
In other words, your example is dated, and really is a dive at the bottom of the bucket to make a point.
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Markus,
It sounds like you have reflective waves from 5 of the 6 wall surfaces. By damping the front wall you have only removed the delayed energy from the one source that would appear to cause the most delay to the listener besides the rear wall which would be the longest path anyway with the most delay. I would think that would clean up the first impulse response at the seating position.
It sounds like you have reflective waves from 5 of the 6 wall surfaces. By damping the front wall you have only removed the delayed energy from the one source that would appear to cause the most delay to the listener besides the rear wall which would be the longest path anyway with the most delay. I would think that would clean up the first impulse response at the seating position.
He has the extensive room acoustics knowledge that not many here have. Not to mention he uses the best measuring equipment in the business. If many here don't have dedicated rooms for their system, I am not sure they would have the cash to purchase a Sim3 system.
Does he have extensive psychoacoustics knowledge?
It's not needed when you have the best measuring equipment
You seem to be pretty upset about something I've said. That wasn't my intention.
I'm pretty familiar with psychoacoustic literature and the truth is that our knowledge in that field is rather limited. I agree that we have to set standards to begin with but I don't agree that current standards are routed in a deep understanding of psychoacoustics.
P.S. What "three tools" were you talking about?