minn_male42 Posted February 4, 2005 Share Posted February 4, 2005 http://www.livescience.com/technology/050202_surround_sound.html here is the text.... When you put on a set of earphones, you hear the Rolling Stones or Yo-Yo Ma as if they were right between your ears. What if you could put those artists out in front of you? This is the goal of binaural sound, which takes into account the shape of your ears and your head to transform a recording into a three-dimensional listening experience. "The idea is to make the ear drums move exactly as they would if they were there live," said Tony Tew of the University of York. Bouncing sound More than stereo and surround sound which try to replicate "being there" by using several speakers emitting separate tracks binaural sound filters a recording by the path that sound waves travel to your ear drums, bouncing off your head and torso then funneling down your outer ear, or pinnae. Because its two tracks are specific to each ear, binaural audio must employ earphones. The idea of binaural recordings has been around almost as long as the phonograph, but it was never individualized to a particular persons features. Instead, it was set up for a sort of average head. "It effectively meant we were listening through another persons ears," Tew told LiveScience. Tew and his colleagues are working on a way to have a person step into a small booth and come out a few minutes later with a reading of his or her binaural "signature." This information would plug into a next generation audio player, allowing listeners to hear effectively through their own ears. Spatial filters The mathematical form of the binaural signature is called a head-related transfer function (HRTF), but "since that is such a mouthful, we call it a spatial filter," Tew said. The filter modifies a recording by basically altering the time delay, volume, and frequency response three cues that the brain uses to locate a sound for each earphone. The simplest to understand is time delay. A sound to the right of you will arrive at your left ear a fraction of a second later than it will your right ear. Because we all have distinct morphologies, a spatial filter needs to be personalized to effectively fool our brains. At present, the only way to get an accurate spatial filter is to use an array of loudspeakers and two microphones placed in each ear. This equipment is expensive, and the process can take a couple of hours. Some military pilots have had their spatial filters measured for binaural sound, allowing for the employment of a 3D warning system, which, Tew explained, can quickly draw a pilots attention to possible danger. But to make spatial filters more commercially available, Tews team has eliminated the audio measurements. Instead, they have figured a way to generate a spatial filter from a few hundred numbers that represent the physical features of a persons head. These "head numbers" can be gleaned from visual images taken by a stereo camera. One complication is that a visual image cannot capture the folds in the ear, nor can it see past the hair to measure the scalp. "We are optimistic that we can guess at the missing bits," Tew said. Practical use Besides immersing people in a virtual aural environment, spatial filters could be used to improve hearing aids, which currently do not take into account the effects of a persons ear and head shape. "We should be able to tailor them for an individual," Tew said. By increasing the amount of directional information, a hearing aid user should have an easier time focusing on one sound, while ignoring others. Tew's group plan to refine their mathematical transformation on 50 or so subjects. Currently, they have been working with a special mannequin called the Knowles Electronics Mannequin for Acoustic Research, or KEMAR for short. "In doing these measurements, sitting still is a big issue KEMAR is just great for that," Tew said. Quote Link to comment Share on other sites More sharing options...
sfogg Posted February 4, 2005 Share Posted February 4, 2005 Binaural recordings can be pretty spooky when listening to them. I have one that is at a race track and the realism on it amazing. The problem with them (like most headphone listening) is if you move your head the perspective moves too which is odd). "Because its two tracks are specific to each ear, binaural audio must employ earphones." That actually isn't true. You need to keep the channel seperation high at your ears for binaural recordings to work which of course headphones do. But you can do that with inter-aural cross cancelation processing with two front speakers as well. Lexicon's Panorama processing has a setting in it for when it is being used to listen to binaural recordings. Shawn Quote Link to comment Share on other sites More sharing options...
sfogg Posted February 4, 2005 Share Posted February 4, 2005 BTW, if anyone wants to hear the recording I'm talking about it is on the Stereophile Test CD #3. http://www.stereophile.com/features/424/index6.html Shawn Quote Link to comment Share on other sites More sharing options...
SCOOTERDOG Posted February 4, 2005 Share Posted February 4, 2005 If my memory serves me right I believe it was JVC back in the early 80's that pioneered Binaural sound. They sold binaural headphones and some kind of black box for them. Not sure if they actually had special recordings or not for them. scooter Quote Link to comment Share on other sites More sharing options...
sfogg Posted February 4, 2005 Share Posted February 4, 2005 Binaural sound has been around for a long time. According to a few sites the first know use of it was in 1881. Here is a place that specializes in these types of recordings... http://www.binaural.com/ Shawn Quote Link to comment Share on other sites More sharing options...
marksdad Posted February 5, 2005 Share Posted February 5, 2005 thats all i do is play at the audio stores, and the cans you speak of just seem like belles and whistles, give me a quality pair of senns or grados, and a good amplifier and you get the music the snake oil salesman are trying to pedal Quote Link to comment Share on other sites More sharing options...
cwm Posted February 6, 2005 Share Posted February 6, 2005 ---------------- On 2/4/2005 1:37:45 PM SCOOTERDOG wrote: If my memory serves me right I believe it was JVC back in the early 80's that pioneered Binaural sound. They sold binaural headphones and some kind of black box for them. Not sure if they actually had special recordings or not for them. scooter ---------------- When I was quite young back in the late 70s, CBC radio out of Toronto had an FM binaural sound drama broadcast once a week.......so 80's??? No...... Quote Link to comment Share on other sites More sharing options...
SCOOTERDOG Posted February 6, 2005 Share Posted February 6, 2005 When I was quite young back in the late 70s, CBC radio out of Toronto had an FM binaural sound drama broadcast once a week.......so 80's??? No.... As I Said, If my memory serves me right I believe it was JVC back in the early 80's The point is to my memory. It could have been the 30's But I was not born then scooter Quote Link to comment Share on other sites More sharing options...
D-MAN Posted February 8, 2005 Share Posted February 8, 2005 I remember a picture of a little foam head with the special microphone "ears" sitting all by itself in a seat about mid theatre with the orchestra on stage for a binaural recording. Must have been in the 70's. The foam head is one like that used in wig stores. For all the fuss, a cheap STYROFOAM HEAD, for crying out loud! DM Quote Link to comment Share on other sites More sharing options...
cwm Posted February 8, 2005 Share Posted February 8, 2005 This reminds of the "Spatializer" circuit used in some TVs etc. to create a simulated surround sound with just two channels. I bought an outboard unit quite a while back and for fun used it with music......the unit comes with 3 levels of 'space' the middle is adequate for movies but the minimum 'space' is interesting to say the least when used for music. I've run it with Quad ES speakers and there are minimal sonic artifacts, and on some recordings the effect is really astounding!! I mainly run my LaScalas with out it now but on occasion loop through the "Spatializer" and it does quite well on some recordings-----makes for a huge and deep sound stage. Anyone else ever play around with this thing or similar?? BTW, Scooterdog, I wasn't trying to sound 'snotty'I just recalled those old broadcasts from way back when I was more innocent, technically and otherwise.... Quote Link to comment Share on other sites More sharing options...
InnovaZero Posted February 8, 2005 Share Posted February 8, 2005 Wow! I just popped on some cans and tried it out, omfg wow! Sounds just like the real thing. I tried it on my loudspeakers, and it was impressive, but not so nearly as much as headphones. Maybe if I mess around with some stuff... Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted February 8, 2005 Share Posted February 8, 2005 I remember binaural sound from the 70's. Actually experimented with it by using a styrofoam wig head model, poking holes in it and inserting the capsules from two Radio Shack condenser mics. Made some awesome nature sound tape recordings during my 'ambient' period. It's a fun experiment, but again, very spooky when listening to playback through headphones. Wish I had those cassettes today. Michael Quote Link to comment Share on other sites More sharing options...
dgb Posted February 10, 2005 Share Posted February 10, 2005 I bought a "NuReality" SRS unit which is basically a space and center control. On some recordings is sounds great, particularly live recordings, on others it makes the vocals too quiet or seems to cut out some bass. Pretty hit or miss. I liked the Carver Sonic Holography unit more. Quote Link to comment Share on other sites More sharing options...
IndyKlipschFan Posted February 10, 2005 Share Posted February 10, 2005 If you go to Disney at MGM, WDW Orlando, FL they have an exibit where you put on headphones and hear things move around you. The most impressive sound to me was the one where someone cuts your hair and you "feel" the sciscors move around you and swear the barbors breath and hair dryer blowing on you... It is downright spooky! (In the animation area where they talk about older disney history, animation cartoons.) Quote Link to comment Share on other sites More sharing options...
dodger Posted February 10, 2005 Share Posted February 10, 2005 I think the use for hearing aids would be better than what's available. As long as they don't feedback the way a number do. Some doing the molds and the fittings need more training. dodger Quote Link to comment Share on other sites More sharing options...
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