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In Reply to: RE: I believe posted by unclestu on November 12, 2012 at 14:17:44
I guess no one got my point about reflections off the stage floor. If you want to think of it, this creates the equivalent of a phantom pair of microphones at a different height. A pulse close to the floor will be doubled with one spacing and a pulse higher up will be doubled with a different spacing. (Looking at one channel. The numbers will be different with the opposite microphone unless the sound was centrally located.) This effect will work over a limited range of height, depending on the size of the venue, position of the microphones, etc. But then, looking at an actual instrumental layout there isn't that much height in the first place when it comes to location of the instruments.
By looking at sound files of recordings of percussive instruments one can sort out these reflections. There will be height information that can be deduced by observing variations in time of first echo. This is one way that humans get positional location. Another way, head related transfer functions, won't work with two microphones in a plane and speakers in a plane. Another way is by brightness, but then one gets into the interaction of instrument radiation patterns and microphone patterns.
There are very strong evolutionary reasons for humans and other animals to have very robust positional location skills, and this undoubtedly means using many different ways to build a model of a sonic landscape. There are probably other ways that have yet to be discovered, but what I mention is well known to sonar engineers and operators, recording engineers, and non dogmatic audiophiles.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Follow Ups:
http://en.wikipedia.org/wiki/Haas_effect
Edits: 11/13/12
Do you notice the forms at the bottom of each post called "Optional Link URL" and "Optional Link Title"?
Here's how they're used:
Hass points out that localization is depending on the arrival of the first wave. Because real music has transient attacks, the waveforms are NOT symmetrical. Reversed absolute polarity can lead to ear "hearing" what may be construed as a delayed waveform, particularly in considering the time delays inherent in many speaker designs. While this generally screws up the localization effects present in many recordings, it would explain why it is difficulat for some to hear spatial localization. I
Hass and Blauert use a lot of white noise for their testing (not all, however). White noise has NO leading edge, making localization cues very difficult (read Blauert's U. Mich. papera, for example).
Dangerous to generalize without taking into account all aspects of the experiments.
I have long been an advocate of proper time and phase alignment of playback transducers. The Measurements which the strange guy desires are already known, mesured and published, but he seems to ignore some fundamentally basic issues, and that is primarly with transducers designs.
Stu
from Dr. Roger West of Sound Lab. He explained that is why he focuses on single driver full range designs. Further, he explained that he suffered a kind of hearing injury long ago with an unusual result. It's not the usual sort of frequency or level specific sensitivity, but it short circuited the brain's ability to to *ignore* dissimilar sounds coming from multiple directions as in a party environment. He finds it difficult to switch off the other conversations and focus on any one.
That is one reason why he is fanatic about sound coherence. I can attest that his speakers certainly excel in that respect.
Hass was working in the horizontal plane. His research (as described in the reference you provided) did not concern itself with height localization, and therefore is irrelevant to this discussion.
You have tried to use research that showed how one things works to prove that another thing can't work. This is pseudo-science. You are stuck in your own dogma. I have nothing more to say to you, it would be a waste of time.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Now you're going to reinvent what Haas' experiments were about?
LOL!!
I was right b4, you truly are lost in a little bubble world of audio fantasy land. The Isolation Ward is ^ thataway.
In your earlier post, you provided a reference:
http://en.wikipedia.org/wiki/Haas_effect
As my reply indicated, this was what I was working from. If you have a different reference that shows that Haas did more, then please provide it, as it would be interesting, and possibly relevant. In case the reference requires payment to read, then please provide brief quotations that would show the relevance of the reference to this discussion.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Edits: 11/13/12
the truly ignorant resort to insults and name calling when they can not answer questions? When asked for documentation they generally use that technique to avoid answering.....
Use headphones to check out what I have written. No sense of height and indeed the spatial presentation is located entirely between the ears, and within your head (there are a few exceptions, generally with phones with drivers located away from the ears). Play the same recording on a simple two way bookshelf, and then turn the speaker upside down: the sense of height is severely diminished (unless the speaker was deliberately designed to be played that way, generally indicating a very "hot" tweeter.
Of course YMMV
Stu
There are funny effects with speakers that involve room interaction, especially tweeters bouncing off room surfaces. However, once these have been cleaned up (through positioning and room treatment) then one can hear effects associated with the surfaces of the recording venue (on a real stereo recording only, of course). If the musical instrumentation is similar to what one is familiar with in live concerts then it becomes possible to understand certain sonic patterns in terms of reflections off of various surfaces. This appears in the time domain as reflections and in the frequency domain as comb filtering. Both of these can provide clues as the microphone patterns, the acoustic venue, etc., and any competent recording engineer would be familiar with these effects and the best ones would be able to place the microphones appropriately to make a nice recording. There is little "height" information directly on most musical instruments at a live concert since the musicians are all on a stage. Sometimes there are risers to elevate those in the back but this amounts to a "tilt" effect and in effect the musicians are still pretty much on a plane. The main acoustic effect in the vertical dimension is bounces off the floor and ceiling. Here the live concert gets a two fold benefit of height information, first from the HRTF in the vertical dimension (asymmetric ear lobes) and second from comb filter effects. There is certainly the possibility for a Pavlovian connection between these two methods of vertical information to be learned, and if so then the comb filtering reflections could get decoded as height rather than just confusing aberrations in frequency response.
Whenever I've listened to headphones, I've been bothered by the "sound in the head" situation, so I don't have much experience using them. In any event, the sound is substantially different from what one would hear in a live environment, so I would have no basis for learned effects (particular sound matched to particular physical location). Perhaps if I were to spend more time listening with phones I might learn to hear more. Of course there are also binaural recordings and these can definitely have height effects, due to HRTF effects.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
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