It's all good... I always value your posts... even if it takes me a few days to fully read them...
Did you put an angle on the end of the pipe to reduce reflections, like on the mic? I put mine in a lathe and made a simple 45 degree cut to imitate the design of the mic.Cool angle stand
I rounded the profile of the plastic pipe with 100 grit sandpaper. I smoothed it until I no longer got a reflection in CSD waterfall plots.
When I started out learning to do gated measurements, I followed the Troels Gravesen guidelines.
http://www.troelsgravesen.dk/measurements.htm
Until now, I had not really noticed an abrupt transition, but now that I know what to listen for, I think I notice it. As I said, I listen fairly close to the speakers, so I am getting a higher proportion of direct sound. If I listen further away, I loose the ability to spatially locate the instruments. I get a sense of envelopment (Toole's term), but localization laterally (left to right) and depth (fore and aft) is diminished. In my room, if I move my seat back by 3 feet, I start to loose the imaging.
The other thing aspect that, to me, is critical to the sense of realism is the volume of playback... If I start at low volume and gradually increase the SPL, at some point there is a transition where the sense of realism is abruptly increased. All aspects of sound are made better, tonal balance, bass articulation, imaging, detail, clarity, dynamics...
j.
Nice! so, at your normal listening situation with roughly 8ft stereo triangle you are close enough and the transition happens somewhere behind listening spot? Now you are a notch better aware of your system, cool cool And I'm more aware of mine, 8ft is more than what I have so I probably have some issue with my system, although you have wee bit bigger room and other differences. Nevertheless usefull datapoint since we (likely) now share experience of same audible phenomenon.
Cool thing about this is that according to Griesinger, and by our small experience, it is quite distinct audible phenomenon and should be about the same for most humans, available with almost any speaker setup regardless of differences and is not too hard to detect if consciously listening for it. A thing we all can share and reason with, together.
Lets assume that the tansition is indeed what Griesinger writes about, a point where brain can't separate harmonics from noise to engage with important sounds. On / off kind of thing with hearing system. He writes that when there is engagement brain makes separate audio streams for direct sound and reverberation/backround sound.
With this assumption you can do further listening experiments. You should now be able to evaluate the two crossover variants you have with wee bit more carefully.
Since you did not notice much difference between good and worse phase match and variation in the DI the differences probably aren't that great. But, the transition distance should be different with the two though, you can now listen for it. Also, you might notice more difference with their in-room responses if you listen beyond the transition, when brain doesn't separate the direct sound and all you hear is the in-room sound. At the close listening the direct sound streams probably sound the same since the listening azis resoonses are about the same, but there might be difference in sound of the envelopment?
Very interesting stuff. Million things you can now try and listen for, and comment here so we can all start comparing ours
Disclaimer, I'm writing what seems reasonable to me based on listening my own setup and having read some of Griesingers papers. It might not be true, but if it is I think its important thing to learn listen for and be aware off. It should help us to tune our stereo systems, to know better what we hear and how written stuff relates to our own perception.
And I'm more aware of mine, 8ft is more than what I have so I probably have some issue with my system, although you have wee bit bigger room and other differences. Nevertheless usefull datapoint since we (likely) now share experience of same audible phenomenon. Cool thing about this is that according to Griesinger, and by our small experience, it is quite distinct audible phenomenon and should be about the same for most humans, available with almost any speaker setup regardless of differences and is not too hard to detect if consciously listening for it. A thing we all can share and reason with, together.
Lets assume that the tansition is indeed what Griesinger writes about, a point where brain can't separate harmonics from noise to engage with important sounds. On / off kind of thing with hearing system. He writes that when there is engagement brain makes separate audio streams for direct sound and reverberation/backround sound.
With this assumption you can do further listening experiments. You should now be able to evaluate the two crossover variants you have with wee bit more carefully.
Since you did not notice much difference between good and worse phase match and variation in the DI the differences probably aren't that great. But, the transition distance should be different with the two though, you can now listen for it. Also, you might notice more difference with their in-room responses if you listen beyond the transition, when brain doesn't separate the direct sound and all you hear is the in-room sound. At the close listening the direct sound streams probably sound the same since the listening azis resoonses are about the same, but there might be difference in sound of the envelopment?
Very interesting stuff. Million things you can now try and listen for, and comment here so we can all start comparing ours
Disclaimer, I'm writing what seems reasonable to me based on listening my own setup and having read some of Griesingers papers. It might not be true, but if it is I think its important thing to learn listen for and be aware off. It should help us to tune our stereo systems, to know better what we hear and how written stuff relates to our own perception.
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btw this can also be reasoned with Griesinger work, which I interpret like so: best possible concert hall sound by him is when there is enough clarity and all that, basically when attention is grabbed by the music, which happens with the proximity and stuff like in previous post, when hearing system can attach to the sounds like they were close. Nearby sounds being the most important ones for cavemen who we still are genetically. Hearing harmonics properly seems to be the key by Griesinger, unscrambled and sufficiently high level compared to other sounds in surroundings. These are the most important sounds for surviving and brain naturally attends to them.
I bet the good listening level you seem to have recognized has to do with it as well. When level is loud enough all the harmonics/detail brain needs to hear to make good engagement/full attention are sufficiebtly high level, above ambient noise of the room. Or something like that.
Have you experimented with SPL meter whats your prefered listening level? what is ambient level in your room? I bet the difference would be quite similar for most.
Might be same or different phenomenon, but in general music sounds better the louder the system is, unless there is some issue which makes it sound bad. Up until its uncomfortably loud. Little below that any system should sound its best.
What is shocking is that the CTA 2034 standard, whose metrics we look at and tune to, does not mention listening distance other than "normal" listening distance, which is propably average found in some study. Now, PIR, which is estimation of average frequency response at where, at normal listening distance? which is what? How PIR relates to perceived sound if this distance is at close or far regarding the Griesinger transition?
Be it close or far, perhaps doesn't matter, but now it has deeper meaning in a way that it probably has not anything to do with listening position sound but sound in general, what the sound is everywhere else in average. And thus gives hint how useful a metric it is depending on which aspect of a system one is evaluating. If you know you are listening in proximity, and tune for that, PIR isn't probably very meaningful, while listening axis/window is and one can now prioritize between, compromize other for the other.
What about Tooles book, does it consider this Griesinger stuff, importance of listening distance? I haven't read it.. but I bet many things in there relate to listening distance and can be tested/experimented at home and reasoned upon after experimenting with Griesinger transition.
Well, again, the important thing is just to know what listening distance works at anyones personal setup by finding the transition distance, to hear the transition. Now any "hifi" sound related writings of audible phenomenon relate to it somehow, either they are relevant or not, depending which side you are at. Are you perceiving direct and room sound separately, or just one mush of room sound. Now that one can relate writings to perceived phenomenon they are familiar with its possible to improve system with confidence, reason what is relevant and what is not. How my setup relates to "average" setup used in all the standards and tests and so on.
Does any of my posts make sense? to me its such a revelation, thanks for experimenting and responding hifijim!
Be it close or far, perhaps doesn't matter, but now it has deeper meaning in a way that it probably has not anything to do with listening position sound but sound in general, what the sound is everywhere else in average. And thus gives hint how useful a metric it is depending on which aspect of a system one is evaluating. If you know you are listening in proximity, and tune for that, PIR isn't probably very meaningful, while listening axis/window is and one can now prioritize between, compromize other for the other.
What about Tooles book, does it consider this Griesinger stuff, importance of listening distance? I haven't read it.. but I bet many things in there relate to listening distance and can be tested/experimented at home and reasoned upon after experimenting with Griesinger transition.
Well, again, the important thing is just to know what listening distance works at anyones personal setup by finding the transition distance, to hear the transition. Now any "hifi" sound related writings of audible phenomenon relate to it somehow, either they are relevant or not, depending which side you are at. Are you perceiving direct and room sound separately, or just one mush of room sound. Now that one can relate writings to perceived phenomenon they are familiar with its possible to improve system with confidence, reason what is relevant and what is not. How my setup relates to "average" setup used in all the standards and tests and so on.
Does any of my posts make sense?
to me its such a revelation, thanks for experimenting and responding hifijim!Hello hifijim,
A suggestion:
"Listening Distance" may only be a hypothetical construct.
Observing the photos in post #285 it appears that your speakers are placed at the left and right ends of a piece of furniture and that he speakers are toed in sort of towards the listening position.
While that microphone is handy place it where you head would be in the first listening position you mentioned. Run your monotone frequency response sweep and record the results.
Move the microphone back to the second listening position that you mentioned and run and record your monotone frequency response sweep and save the results.
Chances are that the FR sweeps are significantly different. The difference between the two Frequency Response curves maybe more about position than distance. (RTA, continuous pink noise, with no gating)
When you made your polar measurements and equalized your speakers the measurements were gated. Room reflections and power curves were only calculations or estimates at best.
If you go read the old Rane equalization white papers, you equalize twice. First you equalize the speakers and post a guard. Second you use multiple microphones or make multiple measurements around the space and equalize the room.
Yes it is all all about direct sound and room reflections.
Thanks DT
A suggestion:
"Listening Distance" may only be a hypothetical construct.
Observing the photos in post #285 it appears that your speakers are placed at the left and right ends of a piece of furniture and that he speakers are toed in sort of towards the listening position.
While that microphone is handy place it where you head would be in the first listening position you mentioned. Run your monotone frequency response sweep and record the results.
Move the microphone back to the second listening position that you mentioned and run and record your monotone frequency response sweep and save the results.
Chances are that the FR sweeps are significantly different. The difference between the two Frequency Response curves maybe more about position than distance. (RTA, continuous pink noise, with no gating)
When you made your polar measurements and equalized your speakers the measurements were gated. Room reflections and power curves were only calculations or estimates at best.
If you go read the old Rane equalization white papers, you equalize twice. First you equalize the speakers and post a guard. Second you use multiple microphones or make multiple measurements around the space and equalize the room.
Yes it is all all about direct sound and room reflections.
Thanks DT
Donate to this man!
Brandon - incoming
https://gofund.me/4c0aa6dc
@augerpro making things better (and easier)!
PS. When you release your speaker designs- are you able to release them as 3D printed or CNC files?
Sometimes I like to DIY, and sometimes I just like to listen to other people's creations without having to ship it halfway across the world.
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Exactly where I got my inspiration too
I love this attention to actual relevant details. They don't have to be expensive - but they are truly important 
That will not work for multiple angles, as with any diffraction it is angle dependent and it cannot be calibrated out other than for a single axis.
My ambient is usually 38 dB SPL A-wt or 45 dB C-wt. When I am at my preferred listening level, my meter set on C-wt “fast” shows an average level of 87 dB, and peaks at 94 dB.
The CTA 2034 standard certainly assumes an average room when making the calculations for early reflections and PIR. That is why the standard can predict what most people will prefer, in most rooms. But it can not predict what any given individual will prefer in a particular room... we are all different, and all rooms are different.
The change that comes with listening distance is noticeable to me, but I would not describe it as dramatic, or profound. It is not the difference between gold sound and manure sound. When distance increases, I mostly hear a change in the 3D image, with localization being the most affected attribute.
I should also mention that when I am in my listening seat, there is a low table (coffee table) between me and the speakers. Left to itself, this has a negative impact on the listening experience. I keep a heavy blanket and a set of pillows in a coset, and when doing critical listening, I arrange these on the table. I have found that this effectively shields me from the floor reflection at higher frequencies. It has no effect on the cancelation null at 200 – 500 Hz, but above 500 Hz I am shielded from the floor reflection. Based on distances, the floor reflection would normally be the first reflection to reach me, followed by the left side wall, then ceiling, then right side wall.
If I listen well back into the room, 16 – 20 feet back, I can hear a difference between the two filters of post #292. My theory is that when listening close, the on-axis sound dominates my perception. When listening at the back position, the sound power of the speaker dominates my perception, and of course there is a difference between the two filters in sound power curves.
Yes it does make sense to me. I also think that it is possible, or probable, that a speaker system with high directivity over the full range (like a synergy horn) might have a longer distance before the transition.Does any of my posts make sense?
perhaps yes... I think the best way to identify reflections near the mic is to measure a well-behaved tweeter and look at the CSD waterfall or burst decay plots.
j.
Doesn't that apply to any calibration? Shouldn't we always keep mic pointed to speaker? When taking off-axis we rotate the speaker on a turntable.
My Minidsp Umic-1 came with two cal files, 0 and 90deg. The 90 is for room rta with the mic pointed up.
Have you guys checked Troels' mic test, here is copy - the effect is shown above 3kHz, not below 120!
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This old paper from B&K shows hows the problem develops, the biggest issue is the return from a 90 degree stand to the capsule. Having the mic in a long enough tube or the arm of the mic behind the mic body gets rid of most of the problem. Wrapping the join in automotive felt or foam works well to get rid of any little spurious reflection from the body or joints.
I've made a mount to attach a 1 to 2m long aluminium tube onto a lighting stand (short test tube in below image)
I've made a mount to attach a 1 to 2m long aluminium tube onto a lighting stand (short test tube in below image)