Nobody is arguing the "ideal", at least I am not. I am arguing from my usual pragmatic approach of concentrating on those things that matter most. And directivity at 200 Hz does not matter as much as it does at 2 kHz.
If I could get 3 dB improvement in DI from 200 Hz - 500 Hz in a pair of speakers, would you pay twice as much for them? Thats what we are talking about here. A dipole is only 6 dB better than a monopole (and a cardiod only about 4 dB) in DI and a 15" speaker at 500 Hz already has 3 dB DI. So while there may be some theoretical benefits, at the very extreme they are not great, and practically speaker they not all that significant at all.
"Perfection is the enemy of the good."
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I dismiss your arguments whatever they are because you are not polite nor objective.
But ITD translated into phase also vanishes as the frequency falls. The ear cannot detect phase differences between the ears at LFs. The two ear signals become completely correlated - no differences and nothing on which the brain can determine any spatial aspects.
What then is the objective and measurable definition of "dynamics"? If a loudspeaker's acoustic output in the room track in level with the input signal over the full range of the recorded source material where would anything more "dynamic" come from ? ? ?
Presumably then there will be something "objective" to measure, rather than a collection of "subjective" opinions (which many good folks don't share)?
but there is onset ITD too, not just ongoing (phase) ITD
isn't it that phase ITD is useless with music under reverberant conditions, only cues from onset ITD are working?
and that onset ITD cue is working regardless of frequency, across the whole audible spectrum?
I am not sure, therefore I'm asking
That's from an introduction portion of his book.
If you read the variety of tests and their conditions that "suggestion" is illusive at best.
In Toole's book there is this tendency to show that yes, this is what matters.. and upon further reading what "matters" is effectively whittled down into "largely unimportant" through gross demarcations in testing vs. our own context, and a string of caveats.
(..in fact most of the research from a variety of sources was synthetic, and often only conditions just one reflection.)
As far as the underlying matter: I'm not suggesting we can't *detect* reflections, but are we particularly sensitive to them under the context of stereo reproduction? (..and again, under the conditions you removed from my earlier post - basically conditioning on moving the loudspeakers away from walls beyond a meter.)
I think one critical thing to point out however, is that the model loudspeaker "type" developed by Olive and Toole - ended-up as a design with low directivity as epitomized by Revel. This form-factor in design was of course heavily researched and included prior knowledge of room-effects along with on-going tests that included listener responses to reflections. This suggests that listener's either weren't sensitive enough to reflections (ie. direct sound dominates), OR if they were particularly sensitive - that they *preferred* any substantial effect those reflections had to offer.
That may be so, but it's not the same as saying that it doesn't matter at all.
Maybe it matters just a little bit less . . . and maybe differences right in the middle of the human vocal range matter more than minor differences in driver directivity up at 2 kHz.
It might have something to do with why it is so hard to fool people that a "voice from a box" is a real person in the room speaking . . .
You focus more on the subject at hand and less on persons and you'll be fine.
You know that the ITD perception will dominate spatial hearing if ITD cues are available. For that to happen in a small room it requires high directivity speaker below 1kHz.
It has been shown in literature and has been discussed numerous times in this forum too the phase difference aka ITD goes down to the lowest audio freqs. Certainly above modal range it will be available.
ITD dominates over ILD, since precedence efect is also based on it.
- Elias
Which I was careful not to say.
And maybe it matters a lot less - are we really arguing about the number of angels on the head of a pin here?
But you see the "aoustic ouput in the room" cannot "track in level with the input signal" because the transducers efficiency is constanly changing as a result of the voice coil heating. This is an instantaneous effect, not a long term one.
Dynamics is not a subject that has been quantified at all. Toole never even mentions it. I have done unpublished tests which show that there are vast differences between drivers and loudspeaker types in this effect - orders of magnitude differences. But at what level is this audible? I have test designs to test this but my wife and I have simply not had the time to do these tests. It takes both of us and one or the other seems to be too busy.
I have also modeled this behavior as well and find that there is an almost 1000 to 1 difference between a 1" direct radiating tweeter and a compression driver. Now this still might not be audible, but if it is, which one do you think it will show up in first?
At any rate, I may drop out of this thread as I am running up too much "on-line" time. It's one thing if poeple are interested, but no one here seems interested. It's just a which hunt.
What is 'onset ITD'? Is it ~'start of a bass wave'? If so, the initial discontinuity creates harmonic content above the fundamental.
He shows the same on page 97. That must be a loooong introdutionThat's from an introduction portion of his book.
You need to steer me to the point in the book, where Toole revokes those diagrams.
Anyway, I wasn't going to support Earl in the first place, but simply showing that you can't count on Toole for support of your argument
Rudolf
Yes there is a glaring flaw, and I've already pointed it out.
Any "importance" in directivity control may not be relegated to reflections alone. Your logic seems fine to me up until the point you make the conclusion in bold italics above. It's like going from A to D - you are missing steps necessary to support your conclusion. If you were to limit it to "hence the importance of directivity control with respect to reflections at 200 Hz cannot be as important as it is at 2 kHz" would work..
-BUT what it wouldn't do is provide the support you need to make the broader claim of: "Mine are CD where it matters most."
Again, that statement is commercial bias.
Moreover a series of logic, no matter how rational - is still just an educated guess. I'd ordinarily have no problem accepting that, but NOT from a person who routinely espouses relying on nothing but utterly objective results - and who often dismisses (.."snubs" really) posts by others for failing to provide that objective data (or same objectivity).
rdf,
Yes there is more to the low frequency wave than a simple sine wave. If we only listened to continuous sine waves none of this would matter but it is so far from reality. How we can distinguish between two drums, one a kettle drum and the other a kick drum is the initial rise time and the other complex overtones that truly make up the sound we are listening to. Even a pipe organ is going to have a start point where the reed opens or a valve opens and this will give us the clues we use to identify what we are listening to and give a very short initial time frame for any localization that quickly is gone. We have to remember we are not listening to test tones when we are listening to music, and I defy you to fine any instrument that has only pure sine way tone generation.
Yes there is more to the low frequency wave than a simple sine wave. If we only listened to continuous sine waves none of this would matter but it is so far from reality. How we can distinguish between two drums, one a kettle drum and the other a kick drum is the initial rise time and the other complex overtones that truly make up the sound we are listening to. Even a pipe organ is going to have a start point where the reed opens or a valve opens and this will give us the clues we use to identify what we are listening to and give a very short initial time frame for any localization that quickly is gone. We have to remember we are not listening to test tones when we are listening to music, and I defy you to fine any instrument that has only pure sine way tone generation.
Guys let's remember to keep it civil, attack ideas not each other.He shows the same on page 97. That must be a loooong introdution
You need to steer me to the point in the book, where Toole revokes those diagrams.
Anyway, I wasn't going to support Earl in the first place, but simply showing that you can't count on Toole for support of your argument
Rudolf
It is in fact a very long introduction.. At it's on page 70, not 97. Page 97 has a different diagram that has similarities.
But the diagram on page 97 is a decent example of where the figure on page 70 is derived from. Page 97 concerns the field of acoustics - specifically real sources in differing sized "rooms". (..notably NOT stereo loudspeaker reproduction.)
On page 70 in reference to figure 5.2 (bottom of the page):
"Figure 5.2 includes repetition of 4.12, which illustrates that, in terms of physical acoustics, the frequency range is divided into two regions connected by a broad transition zone."
"physical acoustics" is specifically referencing the field of acoustics.
That's not to say that there isn't overlap into stereo loudspeaker reproduction, but it's not a "one-to-one" comparison. In fact more than a few acoustical terms get dragged into stereo reproduction that don't meet their own definitions and should not, nor ever were intended to, be used in that manner.
No, I don't think so. What if it matters half as much, one quarter as much? Not a microscopic angel argument, then
Oh now, that's a far too easy out. Just claim that no one is really interested in the subject and it's a persecution party. Come on - you're smarter than that, Doc.
BTW, got the "Think Fast and Slow" book on Kindle. Will start reading tonight.
Naughty boy
You still haven't looked into http://www.hauptmikrofon.de/theile/ON_THE_LOCALISATION_english.pdf ?
Markus had asked you ages ago to take a look. Now please at least read pages 51-53. I just show you this diagram from 1978 for starters:
Do you see how ITD perception can do without those low frequencies?
Rudolf
gedlee;3392984*** said:
This comment is the first interesting one on this thread in a while.
I wonder how much that difference changes if the 1" radiator is in a shallow waveguide, as on some of the Revel speakers or the KEF and TAD/Pioneer concentrics. After all, there's some gain at the bottom of its passband, even if that's not the primary aim of the WG.
This area of research strikes me as one that's more potentially more interesting than directivity just above the modal region, because it should apply more widely.
As an aside, my subjective impression from my short listen (AXPONA last year) was that the Orion is a bit "rounded off" dynamically. How much of that impression was reality and how much of that stemmed from my knowledge that the poor little tweeter was being pushed awfully low, I don't know.