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Old 15th June 2011, 04:49 AM   #21
GeneZ is offline GeneZ  United States
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I do not know if you will hear the same thing. This video made me sense and hear that a mouse, or a big bug, was getting into something to my right as if it were all the way over across the room. It has a clicking type sound.

Listen at a good volume. Around :23 is the first hint of it. At 1:07 is when it was most pronounced. It made me jump the first time I heard it. It should sound far to your right across the room. I listen nearfield.

Can you hear the effect? I wonder how its produced on this video.

YouTube - ‪Lars Danielsson ''Tarantella'' - jazz baltica 2010 (fragm. 1)‬‏
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Old 15th June 2011, 11:14 AM   #22
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Originally Posted by Humdinger View Post
I don't see the difference between what Choueiri is doing and the Bob Carver Holographic generator.

I got curious one day back in about 1983 about what a head mic recording played back through headphones would be like. I think I had been reading the Audio Cyclopedia. I put two Radio Shack condenser mics on either side of a flower pot that was roughly the size of a human head, sitting on my coffee table, and recorded me sitting on the couch playing an acoustic guitar, into a little Sony stereo cassette recorder.

Then I flopped down on my bed with the headphones on and started the playback. The sense of stereo effect, or imaging, was so accurate, that the rustling sound before I actually started to play the guitar caused me to jump up abruptly in fear, before I had time to think. I though someone was in my house. I was dumfounded at how real the stereo effect was. Ever since then I've been a fan of the rather not perfect Carver Hologram circuit. I built it from a grey market schematic someone had, thought the center image was too thin and cold, re-optimized the circuit slightly using the equivalent of a SPICE modelling program (added some reverse Fletcher Munson EQ and another trick that's hard to explain), and now I usually prefer to have it on. Recordings vary mucho on how they are mic'd and processed, so the results are all over the place, but personally, I think it rocks big time. The Preamp I'm designing and building right now will have an L+R output that will help stabilize the center image (the lead singer or guest artist usually), which the Hologram circuit, because of it's critical listening position aspect, makes the center image a little "phasey" as Linkwitz puts it. It seems a bit pushed back or weak. But recording techniques and playback room acoustics will deteriorate the process of cancelling the inter-aural crosstalk significantly, sometimes rather substantially, so you have to judge it carefully, taking into account these variables. I have yet to hear a better way of getting that space, and image individuation where each sound seems to have a sense of its own acoustic space. Whatever it is that gives us a sense of depth works better. Embedded reverbs become 3-D.

It's arguable that the interaural cancellation should only be done to the frequency range of about 100HZ - 2kHZ, since below 100HZ typical room acoustics will have a bigger effect on how we perceive bass, and above about 2kHZ; since the half wavelength is now shorter than the distance between our two ears, our brain doesn't know for sure which period it's trying to compare, so it gives up on measuring timing differences and uses amplitude comparisons instead, from about 2kHZ on up. Up around 8kHZ, our pinea, or outer ear shape apparently gives us cues that tell us about the height of a sound source. I haven't played with that concept yet, but it sounds interesting.
Binaural recordings heard through headphones have been known as far back as at least the early 1960s and maybe a lot eariler. Probably into the 1950s when two track tape recorders became widely available. Some have taken this idea to extremes. This includes building exact replicas of human heads with materials having the same acoustical properties as flesh, bones, and cartilage. JVC marketed a set of headphones having condenser microphones built into them for making binaural recordings in the 1970s. Lafayette radio sold a small dual mike unit for this purpose in the late 1950s. Binaural recordings capture the sound that would fall on your ears if you were sitting in the same location as the microphones and puts them where they would be if you were there, right at your own ears. But the system has a fatal flaw. Can you guess what it is? Choueiri attempts to use binaural recordings played through loudspeakers, he's not the first. He also uses some sort of processor that attempts to cancel the sound of the left speaker heard at the right ear and visa versa. His system uses only two loudspeakers. I don't know what Carver's sonic holography is but it can't be that. There aren't many binaural recordings as a percentage of the commercial market and the processing power Choueiri uses was probably not feasible in the mid 1970s when Carver's preamp was marketed.

Other ambiophonic techniques use stereophonic recordings and for its full realization multiple speakers and additional processors to recreate recording venue acoustics that binaural recordings already have inherent in them. Stereophonic recordings are very different from binaural recordings. In stereophonic recordings made even with only two microphones, the mikes are much closer to the musicians than the audience ever gets and are usually fairly directional (cardiod) resulting in the percentage of recorded sound that is the reverberant field being much smaller. Attempts to isolate and capture this sound or to record the reverberant field and reproduce it as separate channels was the goal of quadraphonic sound in the 1970s. It disappeared from the market IMO because it was a technical failure. BTW, home theater could be called "son of quadraphonic sound." They have much in common.
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Old 15th June 2011, 11:28 AM   #23
rhing is offline rhing  United States
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3D3A Lab at Princeton University

I wonder if Dr. Choueiri would come out to the 2011 Burning Amp Festival to give a talk and demonstration.
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Old 15th June 2011, 01:02 PM   #24
DF96 is offline DF96  England
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Originally Posted by Soundminded
IMO despite this being the accepted conventional wisdom, it's not true. If it were, binaural sound would work. It meets ALL of the criteria of the conventional wisdom yet binaural sound actually has no direction at all. Each sound only has relative differences of intensity between one ear and the other. If binaural sound worked, that's what we'd all be listening to. The only reason not to would be the inconvenience of wearing heaphones.
I think your last sentence sums it up (the rest is wrong). Binaural sound only works through headphones, but then it can work extremely well. Headphones are inconvenient for joe public, and until recently the wearing of headphones marked a person out as a nerd. Now headphones are trendy, maybe binaural will make a comeback.

Now I suppose it is just about possible that your hearing is unusual, so binaural doesn't work for you, but you can't extrapolate from one person's hearing and declare an accepted part of science is simply wrong. You need more evidence than that.
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Old 15th June 2011, 02:25 PM   #25
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I think your last sentence sums it up (the rest is wrong). Binaural sound only works through headphones, but then it can work extremely well. Headphones are inconvenient for joe public, and until recently the wearing of headphones marked a person out as a nerd. Now headphones are trendy, maybe binaural will make a comeback.

Now I suppose it is just about possible that your hearing is unusual, so binaural doesn't work for you, but you can't extrapolate from one person's hearing and declare an accepted part of science is simply wrong. You need more evidence than that.
You are mistaken. What's wrong with binaural recordings played with headphones is that when you turn your head even slightly, the sound turns with it. Your brain immediately comes to the only conclusion it can, that the source of sound is inside your head. Among the extreme attempts to fix this problem have been "nearphones" which are an array of tiny speakers mounted in an enclosed chair or swing, each pair playing sound recorded with separate pairs of microphones, and the same idea using accelerometers to sense head movement changing from tracks with one recorded microphone pair to another played through headphones. These schemes are impractical and don't work. Binaural technology has been a failure. When you truly grasp the reason, it becomes ovious why it can never be made to work.
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Old 15th June 2011, 03:28 PM   #26
DF96 is offline DF96  England
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I accept that this is a disadvantage of binaural, but it does not necessarily bring the sounds inside your head. I guess it may depend on how much you normally move your head during live music.

However your claim, IIRC, was that the alleged failure of binaural is because the normal explanation of stereo (phase at LF, amplitude at HF) is wrong. The 'sound in head' argument does not address this issue so is a red herring.
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Old 15th June 2011, 04:10 PM   #27
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Originally Posted by DF96 View Post
I accept that this is a disadvantage of binaural, but it does not necessarily bring the sounds inside your head. I guess it may depend on how much you normally move your head during live music.

However your claim, IIRC, was that the alleged failure of binaural is because the normal explanation of stereo (phase at LF, amplitude at HF) is wrong. The 'sound in head' argument does not address this issue so is a red herring.
As I pointed out previously the binaural recording/playback system using headphones meets all of the criteria set forth in the 1907 paper but it does not convey directionality of sound. This may seem confusing because all of the reverberation is there and the sources can have different points of origin between your left and right ears but that is not true directionality. What is true directionality? It's when you can suddenly hear a sound and turn your head in the direction it is coming from. You can't do that with binaural headphone sounds but you can in the real world and that makes all of the difference. I'm not at liberty to give you a further explanation of why but this has long been known as the fatal flaw of binaural sound.
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Old 15th June 2011, 05:36 PM   #28
DF96 is offline DF96  England
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Two different but related issues: determining direction, and responding to that direction. If we particularly wish to locate the direction of a sound we may turn our head, but surely when listening to music the main interest is the sound rather than where it is coming from? Direction is a secondary effect. We can enjoy music in mono, but we would not enjoy music with pitch or rhythm errors.

Given that some people now choose to listen with headphones, a binaural signal (either recorded that way, or processed from normal stereo) would be better for them than normal stereo.
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Old 15th June 2011, 05:54 PM   #29
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Two different but related issues: determining direction, and responding to that direction. If we particularly wish to locate the direction of a sound we may turn our head, but surely when listening to music the main interest is the sound rather than where it is coming from? Direction is a secondary effect. We can enjoy music in mono, but we would not enjoy music with pitch or rhythm errors.

Given that some people now choose to listen with headphones, a binaural signal (either recorded that way, or processed from normal stereo) would be better for them than normal stereo.
The ability to detect the direction of the source of sound is one of the most critical elements in hearing. It is among the reasons higher animals developed hearing in the first place and why it developed binaurally. The hearing of the presence of a new element in the environment and the ability and instinct to turn your head towards it quickly and accurately so that you can look straight at it is a key asset for survival. While directionality is not one of the four basic elements of music, it is an important component in its appreciation for many reasons including some I won't discuss. But its importance is reflected in the commercial success of stereophonic sound over monophonic sound even if it wasn't as well developed as more channels would have made it and the technical failure to understand it sufficiently was a key element in the failure of quadraphonic sound. It is also one of the main driving factors behind ambiophonic sound.
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Old 15th June 2011, 06:48 PM   #30
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The Carver Holographic generator (early version - he may have modified it by now) uses 125uS all-pass delay (I SPICE'd the circuit). It sends an inverted, delayed and attenuated (roughly 5dB) signal to the output mix of the other channel, and vice versa. The circuit is not recursive, but I'm not sure how much that would improve it anyway since a typical listening room side wall reflections and width of speaker diaphrams will limit how good it can work. Apparently the patent ran out on the Carver circuit and now others are marketing it as their own thing. I thought the original binaural recordings were done in the 1930's. I think Soundminded is expecting too much. No method is capable of being perfect. The better question is does it make the listening experience better. More emotionally involving. More theraputic... Who needs to turn their head when listening to a good CD or DVD?
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