Originally Posted by Randy Bessinger
"Floyd was ambiguous about VER in his book, but in long conversations with him I nailed him down on the subject. He does say that VER "appear" (from the limited data) to be "prefered" to not having them. He also found this surprising since it is not what he expected either. However, the tests were such that what I recommend was never tried. He looked at situations with and without VER and found a preference for them, but that preference was based on a preference between the various alternatives and not all the alternatives were represented. In Floyd's style of tests it's very hard to control all the variables. For example, his directivity tests were based on a narrow directivity Quad speaker versus other wider directivity sources. But that's as much a test between the Quad's over-all sound quality and the other speaker as it is about directional versus non-directional. It's hard on some of this stuff to draw conclusions from the tests because so many variables have been changed.
His book is excellent and the only place where Floyd and I disgree is in the first 10 ms. Other than that we are completely on the same page. And in this 10 ms region, I find his data and his conclusions to be somewhat weak, certainly weaker than all else in the book."
1. Earl has deep background in this science and importantly understands the math. So I would take note of whatever he has to say. So please don’t take this as me not respecting his immense knowledge which in some areas goes well beyond mine and anyone else for that matter in this thread.
2. His beside manners and impression of human interactions leaves something to be desired. Sadly I know that first hand with him reading the identical situation differently than the few of us present in the same situation. So I would not put any weight on him "nailing" anyone much less Dr. Toole. That’s just the way he talks sometimes.
3. He is not specific in what he nailed Dr. Toole on. I don't know what he means about the tests not being specific either. The AES Journal paper by Toole and Olive is very specific, ranging from anechoic chamber to real rooms. On that front, it is strange that he would rely on the book and not the AES journal papers on which the book is based. Or why he has not published a paper demonstrating otherwise.
4. In the other post you quoted from him, he mentions Blauert as his research source. Dr. Toole extensively quotes him so it is not the case that Earl has discovered a source that Dr. Toole has not. Indeed, if you read Blauert's book, you see references to Dr. Toole's research! Here is a choice quote in Dr. Toole's AES paper:"Fortunately such events are rare. Most reflections arrive from directions different from the direct sound, and perceptions vary considerably. Two ears and a brain have advantages over a microphone and an analyzer. The fact that the perceived spectrum is the result of a central (brain) summation of the slightly different spectra at the two ears attenuates the potential coloration from lateral reflections significantly . If there are many reflections, from many directions, the coloration may disappear altogether , a conclusion to which we can all attest through our experiences listening in the elaborate comb filters called concert halls. Blauert summarizes: “Clearly, then, the auditory system possesses the ability, in binaural hearing, to disregard certain linear distortions of the ear input signals in forming the timbre of the auditory event” ."
Doesn’t seem contrary to Dr. Toole’s views and says the same thing I explained earlier regarding our hearing system and detection of comb filtering.
5. Earl has a very specific point of view in acoustics and audio. That specific idea is the heart of his speaker business. That idea relies on the premise that a reflection that arrives at the same ear that is hearing the direct sound is bad. So right ear hearing the reflection from right is to be avoided. As a result, he designs speakers with narrow angle (< 90 degrees) that have constant directivity. Hence one is able to tilt them such that each ear only hears its direct sound and reflection is presented to the other. Read his paper if this is not clear. But take away the message that his entire premise is for not if Dr. Toole is right. That you can build speakers with good off-axis response and then let the side reflections – even those facing your ear – be there to enhance what you hear. It is an interesting theory but I am not there unless he can show blind listening tests that demonstrate it to be superior. I have it for the other camp.
If you read Earl’s white paper you see that unlike Dr. Toole’s, there are no references regarding the same ear reflections being bad. He only asserts them. As I said, he is an industry expert and his opinion is to be noted. But that is as far as I go. I can’t rely on it if it doesn’t show listening tests of his own or work of others. Dr. Toole provides all of that. So forced to pick between two titans, I take Dr. Toole’s answer since it is backed so extensively and published so broadly.
Note also that Earl essentially advocates an empty room devoid of any treatment. He feels that late reflections are good and any absorption will take them away and that is a bad thing. From his paper:” Also consider the fact that absorbing material placed in a small room is orders of magnitude more effective than this same material placed in a larger room. This happens because virtually all sound absorption takes place at the enclosure boundaries and a sound wave in a small room strikes these boundaries an order of magnitude more times in a given period of time than it does in a large room. Thus, even small amounts of sound absorption in a small room can lead to an over-damped condition - especially at higher frequencies. This over-damped situation is a big problem in many small rooms.”
So if you want to believe in what he has to say, then you have to believe all the way. You can’t take apart one bit and run off with someone else’s formula. You can’t say you rely on one part of his opinion and then proceed to start absorbing or otherwise messing with these reflections.
6. I don’t know if on purpose or otherwise Earl is making a generalization about Dr. Toole’s position which simply is not true. He is not telling you all early reflections good. Indeed as I noted way back in the thread and indirectly to Dragon just now, some reflections from the floor do need to be mitigated. They do color the sound. Likewise there is no benefit from front and back wall reflections so absorption can be put there. Nor is there talk of encouraging diffraction or anything else for that matter just because they are caused by reflections. Our feeling of spaciousness occurs when the two ears hear different things (i.e. less “correlated”) and that happens with side reflections and hence the reason we like them.
Anyway, wish I had the specifics here of what he had talked about with Dr. Toole. I will see what I can dig up. For now, that should be plenty of “comments” to chew on