Wayne, will you please clarify your comment about pitch and roll, as mentioned in the "Ultimate Soundstage Tuning" section? I am interpreting it as is shown
here. and assuming that the nose of the plane is pointing directly at the listening position equates to a line perpendicular to the panel running through the listening position. So changing the yaw of the speaker is changing toe-in angle, for example.
Yes, that is correct. I should have been more specific. The linked illustration and your description show exactly what I meant.
I interpret from your comments that you played around with roll (ie with the panel's long axis not perpendicular to the floor), which surprises me so I thought perhaps I am not interpreting this the same way you are.
I did not "play around" with the "roll." Rather, my carpeted basement floor has some slightly uneven areas, which include around the spots where both ESL speakers sit. At one point in the experiments, the imaging became very soft, and I eventually realized that the ESL position relative to that floor unevenness had the "roll" slightly off-vertical. I used a level across the top of the panel (be sure it is exactly straight across) to adjust the "roll" back to perfectly vertical, and the image clarity improved dramatically. I was surprised at how sensitive the image clarity was to this slight error.
So it is not a variable to play with, but rather a potential pitfall which must be watched closely. Precisely zero "roll" is the only acceptable orientation.
My idea of changing the pitch of the speaker was that if I was sitting in the PLP and was 30 degrees off-axis to the left and right speakers, and the center speaker (at 0 degrees) sounded bright in comparison, I could tilt (or change the pitch of) the center channel to "turn its highs down" a bit and make them closer to timbre matched at the PLP. Although, now that I'm thinking about it, I probably would just keep the left and right channels at 15 degrees for cinema, making this a moot point.
The "pitch" also has to be just right, although the actual value can be different for the two speakers (couldn't just ONE little thing be simple?????). With a mirror taped to the wall and a laser distance finder reflecting from LP to mirror to ESL and back to mirror and LP again, one can determine (with some experimenting with the mirror location on the wall) right where the main reflection points are for the rear waves. Upon trying this, it became clear that my wall was not perfectly flat, and that the reflection points differed in height on the wall by several inches. The best image clarity was achieved by adjusting relative pitch so that the rear waves were coming from the same heights of the two speakers. When you look at the distances and angles, you can see that adjusting "pitch" affects the point of origin for the rear wave more than it does the front (there, ONE factor that makes setup a LITTLE bit simpler), so the "pitch" will be adjusted initially for the proper rear-wave path from panel to LP, then fine-tuned by ear for image clarity later on. This adjustment also was quite sensitive. I resorted for convenience to propping the back of one ESL with paperback books just so I could vary the "pitch" quickly, and found that the difference of thickness of a
few pages there could affect the image clarity noticeably, from "pretty good but sounds a little bit strained" to "totally natural and relaxed."
It will depend on what qualities you prioritize. Your statement above is essentially correct, but if imaging is a priority you will have little leeway in playing with "pitch." For frequency response matching, you might be able to vary it more, but that is essentially what was being done to adjust imaging, so I am not sure now much you can vary it in practicality.
Also, for stereo listening I'm nearly always alone. Stereo listening is a bit of a solitary adventure, almost by necessity. The position of the left and right speakers in a cinema setting carries constraints that will likely make it less than ideal for soundstage and imaging (at least in my smallish room). In my setup, for example, I would probably have only 2.5 feet between the speakers and the front wall, and the speakers would be either behind the AT screen or immediately to the sides of the screen. So for stereo listening, I would try to find the best position, and then move the speakers back and forth depending on what I am doing.
Sonnie has done this successfully. Taped targets on the floor plus precise laser distance meter measurements and laser-guided angle adjustments can give pretty satisfying results. The ultimate soundstage results require that measurements get mighty close, though. I adjusted for impulse delay matching front and rear, as shown, which gets down to 1/10th inch distances and fraction of-degree-angles. As mentioned, however, it did turn out that using the "thickening" slats on the wall allowed that precision requirement to be relaxed a bit, so movement back & forth with a few minutes allowed for positional fine tuning might work.
The soundstage without the slats and with precision delay matching is remarkable, but adding those thickening slats makes the depth acuity and density cine alive.
See, you're not as crazy as you think . . . well, maybe you are but you're not alone.
This hobby seems to foster obsession and related disorders!
Yeah, if one has the slightest OCD tendency, this hobby will really get under his skin (scratch, scratch).
I only care about others' experience when there's a movie playing, and hope to be able to achieve an experience that is similar for everyone that is located inside the left and right boundaries of the screen. In my case, that would mean no one is more than 25 degrees off-axis from the center channel. Maybe only 20 degrees most of the time, and we will not worry too much about that guy at 20 degrees :whistling:
I think you will be very satisfied with those criteria.