People say I "cheat" by using the inter-aural cancellation circuit, and god forbid Tone Controls, and freakish speakers (open baffle), each of which are a decided step away from "fidelity"... I'd love to see what Lewis Black would have to say about this, if he were a well educated audio engineer.
To me, trying to recreate a very real playback experience is much like re-hydrating dehydrated food. Following the conventional rules of "high fidelity" is ********. Inter-aural crosstalk WILL screw you out of being able to decode imaging information in the 100HZ - 700HZ range. Listening room acoustics WILL in most cases damage most of the frequency range, but in a good room, may only do serious damage to the lower mid and bass. The concept that mics don't hear like our ear is very real. You're given a recording that is already full of damage, and expected to make it sound real and great, using a minimalist approach. Actually, forget the analogy; rehydrating food works MUCH better.
Right on, Bob. And the biggest single rule of hifi that is ******** is the rule against having any tone controls or equalisation.
I quite agree that the polar pattern that we seek must be support by psychoacoustic principles, but in my mind the question does not "remain", the answer has been firmly settled. Others disagree, most notably Toole, but I think his data and his position in this regard are weak. His position is based on "preference" tests where what I claim to be the correct approach was not tested. So perhaps the proof "remains" to be shown, but a sound hypothesis exists. (Pun intended.)
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Correct me if I'm wrong, Earl, your studies have demonstrated the audibility of various elements of room contributions, and have demonstrated their effect on intelligibility.
Toole demonstrated preferences, which faces you both against the old "production versus reproduction" chestnut, IMO.
Personally, I prefer your approach for it's logic, offering that it seems to get down to the nuts and bolts of the issues. However, I can't help thinking that there is a third point of view.
It is the question of whether the room wants or needs to be heard. Normally I can reason that my room is/was not a part of the production chain. It isn't practical though, to eliminate the room...and debatably it isn't necessary as you have demonstrated crossed-purposes (I mean differing effects or priorities) in both the temporal and the frequency domains.
Do you also feel you have reasonably demonstrated that this gives us license to cut early, and encourage late reflections? or did you simply notice that it indeed has benefits in sound reproduction? Simply seeking to exploit reverberations to enhance the experience (or even intelligibility (in this specific case) for that matter) seems to come back to production verses reproduction.
Now, if it sounds like I'm accusing you of being subjectivist, I'm just looking at the thread title.
As a side question I wonder if this has an effect on the synergy of the room contribution as a whole but I feel you may have answered this well enough in your papers. I would cite the experiences of omnipole and dipole enthusiasts over this point (while reserving judgement, myself).
Toole demonstrated preferences, which faces you both against the old "production versus reproduction" chestnut, IMO.
Personally, I prefer your approach for it's logic, offering that it seems to get down to the nuts and bolts of the issues. However, I can't help thinking that there is a third point of view.
It is the question of whether the room wants or needs to be heard. Normally I can reason that my room is/was not a part of the production chain. It isn't practical though, to eliminate the room...and debatably it isn't necessary as you have demonstrated crossed-purposes (I mean differing effects or priorities) in both the temporal and the frequency domains.
Do you also feel you have reasonably demonstrated that this gives us license to cut early, and encourage late reflections? or did you simply notice that it indeed has benefits in sound reproduction? Simply seeking to exploit reverberations to enhance the experience (or even intelligibility (in this specific case) for that matter) seems to come back to production verses reproduction.
Now, if it sounds like I'm accusing you of being subjectivist, I'm just looking at the thread title.
As a side question I wonder if this has an effect on the synergy of the room contribution as a whole but I feel you may have answered this well enough in your papers. I would cite the experiences of omnipole and dipole enthusiasts over this point (while reserving judgement, myself).
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Correct me if I'm wrong, Earl, your studies have demonstrated the audibility of various elements of room contributions, and have demonstrated their effect on intelligibility.
Do you also feel you have reasonably demonstrated that this gives us license to cut early, and encourage late reflections? or did you simply notice that it indeed has benefits in sound reproduction? Simply seeking to exploit reverberations to enhance the experience (or even intelligibility (in this specific case) for that matter) seems to come back to production verses reproduction.
Now, if it sounds like I'm accusing you of being subjectivist, I'm just looking at the thread title.
One cannot avoid some subjectivity, but the goal has to be to elliminate it as much as possible. Science is supreme, but extremely time consumiing, so sometimes we take short cuts and sometimes those cuts kill the patient. Its all a trade-off where the more you understand them the better your results are likely to be. Its the idea that subjective evaluations are supreme that is the giant gorilla in this room.
I have never done room acoustics studies professionally, but I have studied the problem to the extent to understand what the goal is.
What we all want, I presume that we all want the same things, is good imaging AND good ambiance, or spaciousness. What you find is that these two things are counter opposed in the vast majority of setups. When one optimizes one then they rave about that design approach because of this feature, while another optomizes the other and raves likewise. I claim to be able to do both, and, of course, I rave as well.
It will all work out in the long run, but I have enough converts that I am comfortable with my approach.
Oh, you mean how much "time" you have to put in on building them, and what "frequency" that's likely to happen in... Yes, we have busy lives... it's a bitch.
Thanks for the translation !
According to google translator Blauert's directional bands Blauertsche Bänder = Czech blue ribbons
My goodness !
Time for conclusions !
There are two frequency bands important for stereo imaging to generate the image in front: 300-600 Hz and 2.5-6 kHz.
but these are in the median plane exclusively for front-rear when all other spatial cues are ambiguous/conflicting
how can these be bands important for stereo that is about horizontal plane
I believe there is a huge misunderstanding
I found that a design that minimizes early reflections raises perceptual importance of single reflections (and there is scientific proof for that). When using a high directivity toe-in setup, the contralateral reflection can be too loud and it becomes a localization cue. The sound stage becomes narrower.
Additionally there seems to be a misunderstanding about the wording. Spaciousness is LEV and ASW. The ambiance resulting from a high directivity setup can create some LEV but not an increased ASW. For an increased ASW reflections are too low in level and they are coming from the wrong directions.
A design that does good imaging and spaciousness (including ASW) at the same time requires more than two speakers.
By the way, do you have ETC data from your room?
underline mine
...and someone was talking above about quasi-religious attitude
underline mine
seems that at least some of Your clients disagree and Your church is losing converts
check out this one:underlines mine
more in this thread:
underlines mine
thank You Markus
so Dr Geddes - it seems that Your claim to be able to do both is objectively unfounded
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I only claim to be able to do both if the room is properly configured to match the high directivity loudspeakers. Markus has never done that. He needs the loudspeakers alone to achieve his results and leaves the room as a given (thats the problem with renting I suppose). In this situation you will still have the tradeoff.
Markus - I do not consider ASW and spaciousness to be the same thing. To me spaciousness is the sense of the rooms "space" - its acoustic size. In a recording the ASW - or "image" is mostly set by the recording and if it is played back properly will be recreated as it was recorded. (You will have to refresh my memory about what LEV is.) Sure many early reflections will increase the ASW while they smear the image. Some people consider this to be a good thing and with some types of music it might be, but for a solo vocalist this kind of smearing is not a good thing.
In certain situations the contra-lateral reflection could be a bad thing if it were large enough and soon enough, but this reflection by swamping it out with a multitude of other reflections does not seem like a good thing to me.
No, I have not done a ETF of my room as yet. I want to and may do that soon now that I have a more portable mic preamp.
Markus - I do not consider ASW and spaciousness to be the same thing. To me spaciousness is the sense of the rooms "space" - its acoustic size. In a recording the ASW - or "image" is mostly set by the recording and if it is played back properly will be recreated as it was recorded. (You will have to refresh my memory about what LEV is.) Sure many early reflections will increase the ASW while they smear the image. Some people consider this to be a good thing and with some types of music it might be, but for a solo vocalist this kind of smearing is not a good thing.
In certain situations the contra-lateral reflection could be a bad thing if it were large enough and soon enough, but this reflection by swamping it out with a multitude of other reflections does not seem like a good thing to me.
No, I have not done a ETF of my room as yet. I want to and may do that soon now that I have a more portable mic preamp.
....<snip> thank You Markus
so Dr Geddes - it seems that Your claim to be able to do both is objectively unfounded
I think subjectively unfounded, based on one subject.
I also believe it is settled but I think the decision is that no particular polar pattern offers a real advantage.
If you read the various threads of this forum you'll see that there are many camps where people have "found the solution" Tubes are better, triodes are especially good, single ended triodes are best. Dipoles are the answer, CD horns are the answer. Transmission lines, Carlson enclosures (shudder), omni speakers, linear phase, 1st order networks, the list is very long.
There is a germ of truth in each camp, or at least a technical aspect that their ideal technology has at its core: CD polars look really good, linear phase systems pass a square wave. "It must be a good thing."
Now I was working with CD systems, as you know, considerably before your commercial endeavours, then multi-element line arrays, then lobe free expanding arrays. I would love to find that one of those technologies was "the answer". But seeing a performance advantage (passing a recognizable square wave, for example) and proving that it makes a difference to listeners are two different things. This is an amateur forum so people are entitled to their beliefs and the fun of debating them endlessly. Still, it would be nice to think we could make some progress in the science of sound reproduction and push the ball down the field, even a little, towards truly improved systems. This would require distinguishing between what really matters and what doesn't.
What is fairly settled is the significance of reflections in a domestic room. Soren Bech studied this pretty thoroughly and others seem to have either corroborated or at least not contradicted it. I think Toole's studies are more definitive than you do, and I don't think any magic speakers were overlooked. There were plenty of systems with enough variety of polar curve to show a preference towards better polar curves, even if perfect CD performance was never tested. None of his results point towards a link between polar curves and preference. His unambiguous results in testing the ESL63 suggest that a pure CD system wouldn't fare especially well (the link being higher than normal directivity and extra polar uniformity).
As to being "preferential" tests, having struggled for years at small loudspeaker companies I would have been happy to increase sales with a speaker that was "preferred" even if I couldn't prove it was absolutely superior.
Here are some things I think we do know. In a typical room certain early reflections can be audible, most of the later reflections are not individually audible. Power response and in-room frequency response are poor indicators of perceived response. Vertical reflections and lateral reflections are perceived differently. Vertical reflections are hard to separate from the direct sound and are more likely heard as colorations. 2 channel reproduction forces a compromise between clarity and spaciousness (we agree). Being more directional than the norm will divorce a system from our listening space and some listeners will not prefer that. (But others will.)
The problem is that most of the idealized polar patterns that we can achieve bring higher directivity along with them, and that is apparently a poor compromise. If these especially good polar paterns only bring an improvement to far off axis response, then there appears to be no subjective benefit to this, the axial response is so much more important.
Our problem varies by frequency range. Floor bounces are audible and strongly impact the middle hundreds. We can solve that problem for those frequencies, but the solution doesn't apply to frequencies below or frequencies above.
There is no ideal directivity pattern for stereo speakers.
David S.
Huh? I guess my setup is much closer to your recommendations than what I've seen from others or am I missing something?
We're probably talking about two different perceptions that are commonly assigned to ASW. ASW as a description for not being able to pin-point a sound ("out of phase") and ASW as a description for a sound that fills a space. There's no ambiguity connected with the latter. It sounds "real". "Early spatial impression" might be a better term. Lateral reflections >5ms (better >10ms) create this sensation.
Try a toe-out of about 20°. Even without equalizing the resulting amplitude distortions you should get a wider and more spacious soundstage. The frontal part of the room has to be highly symmetrical for this to work.
The problem is that this contralateral reflection can become detrimental if it is the first early reflection that sticks out.
Would love to see that. It might help answering why you don't get the narrow stage from contralateral reflections.
I don't quite follow here. If we can solve floor bounce at low midrange frequencies by use of a low mounted woofer, how does that not also solve floor bounce at even lower frequencies ?
If a woofer is close enough in fractions of a wavelength to the floor to eliminate floor bounces at ~ 300Hz then it must also by definition be close enough at all lower frequencies where wavelengths are even longer.
Of course at modal frequencies all the other room boundaries other than the floor become an issue too, but if the woofer is at the floor that's at least one boundary - the closest one - that won't be giving you destructive interference below a certain cut-off frequency.
At higher frequencies a different approach must be used though, yes.
David, great post! I agree with most of what you said.
Don't you think there was strong emphasis on conventional forward-radiating box speakers?
In order to determine the role of directivity, other parameters have to be controlled. The ESL63 has other problems which may have caused it to rank lower. It's response is neither very flat, nor smooth - two things that have been proven to be very important. Do you know of any other higher than usual directivity speakers that were tested by Toole and about which he published?
Don't you think there was strong emphasis on conventional forward-radiating box speakers?
In order to determine the role of directivity, other parameters have to be controlled. The ESL63 has other problems which may have caused it to rank lower. It's response is neither very flat, nor smooth - two things that have been proven to be very important. Do you know of any other higher than usual directivity speakers that were tested by Toole and about which he published?
This was precisely the point that I made to Floyd when we discussed this, and no, no other narrow directivity speakers were used, his position on this is based entirely on that singular result.
Dave, we will have to disagree on the directivity thing because my experince says that it is not an insignificant factor. The distribution in time of the reflection and reverberation cues are strongly affected by the speakers directivity (at least in a small room) and these things are know to be strongly correlated with perception. So it seems untenable to me for you to claim that it doesn't make a diference. That there is a mix of opinions on the "preference" for one over the other is certainly true, meaning that there is no "ideal" in the sense of a universal preference of one for the other, but that there is "no difference", I do not accept. But I would contend that if there is a difference then there is one approach has to be "better" than the other - defining "better" being the key point of contention here.
Maybe you agree with that, I am not sure, but your comments made it sound like you didn't believe that there was a difference.
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Well said. Audio reproduction is full of compromises. We pick and choose which compromises we can live with. Others may have different priorities.
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