craig@reed.UUCP (Craig Deforest) (03/20/89)
In article <453@corpane.UUCP> sparks@corpane.UUCP (John Sparks) writes: >Hmm, In theory you can try taking two speakers from a stereo system and >wire one of them opposite polarity from the other. [and get nothing out] >... >But in reality this won't work. Since each sound source is the center of >a 3 dimensional spheroid of sound waves, They would have to both be located >in the exact same space in order to cancel out. Hmm. This brings up the interesting topic of sound holography, which was (I seem to remember) going on at U.C. San Diego some years ago... Sound holography works just like optical holography, except that the wavefront can be constructed 'by hand' with a wall full of speakers, since speakers are about (!) the same size as sound waves. Of course, there's the small ;-) matter of feeding the right sounds, with the right delays, to all of those speakers, even after you've figured out what you need to do to produce the desired image... The possibilities are obvious. I even recall a simple (trivial) case of sound holography for the home audio- phile: in 1985, some high-fidelity *electrostatic* speakers were put on the British market: a pair of plastic membranes had several metal foil capacitor plates which charged and discharged, producing sound waves. The neat part was that there were several such capacitors on the membranes, which were fed through linear phase (read: 'constant time') delay amplifiers, to reproduce the wavefront that *would* happen if the sound were coming from a point source 15cm (or so) *behind* the membrane. They sounded great! :-) Does anyone know anything about other applications or experiments with acoustic holography? Please followup or send email; I'd like to know more... -- =========================================================================== "Well, the universe _IS_ linear, | craig@reed.BITNET -or- at least to first order..." | ....tektronix!reed!craig ===========================================================================
cook@stout.ucar.edu (Forrest Cook) (03/22/89)
In article <12109@reed.UUCP> craig@reed.UUCP (Craig Deforest) writes: >Hmm. This brings up the interesting topic of sound holography, which was >Does anyone know anything about other applications or experiments with ... Go see a Grateful Dead show, they have been doing this for years. If you can manage to get tickets, that is. :-) ^ ^ Forrest Cook (Opinions, Boy, Those were just Opinions) /|\ /|\ cook@stout.ucar.edu (Foghorn Leghorn) /|\ /|\ {husc6|rutgers|ames|gatech}!ncar!stout!cook /|\ /|\ {uunet|ucbvax|allegra|cbosgd}!nbires!ncar!stout!cook
gbell@pnet12.cts.com (Greg Bell) (03/22/89)
Ever heard of Holophonics? Pioneered by a company called Zuccarelli
Holophonics. They have a demo cassette tape for $15 that is FASCINATING. On
a good tape deck, with headphones, the effect is amazing. Not only do you get
the left-right effect as is typical of stereo, but you also tell up and down
directions and forward and backward directions. Popular Science had a littl
e writeup about it in a Science Newsfront a while ago. The first side of the
tape has sound effects, while the second has music. The first side is the
most interesting. These are the sounds included:
Removing jacket
Matches
matchbox shakes
scotch tape
haircut/hairdrier
balloon
lemonade
newspaper
plastic bag
whispering voice
bees/water
birds and airplanes
fireworks
model airplane
racing cars
rain with thunder
The haircut track will make you flinch! You can tell where the scissors are
around your head!
The $15 price includes shipping and handling charges. 6.5% sales tax for CA
residents. If anybody's interested in ordering or more information (they sent
me a few articles), their address is:
Zuccarelli Holophonics, Inc.
PO Box 64770-294
Los Angeles, CA, 90064
As is customary to say, I'm not affiliated with this company...
Greg Bell_________________________________________________________
Hardware hacker |
Electronics hobbyist | UUCP: uunet!serene!pnet12!gbell
EE major at UC San Diego |alanc@boulder.Colorado.EDU (Alan Craig) (03/23/89)
In article <580@serene.UUCP> gbell@pnet12.cts.com (Greg Bell) writes: > > > Ever heard of Holophonics? Pioneered by a company called Zuccarelli >Holophonics. They have a demo cassette tape for $15 that is FASCINATING. On >a good tape deck, with headphones, the effect is amazing. Not only do you get >the left-right effect as is typical of stereo, but you also tell up and down >directions and forward and backward directions. About three or four years ago the BBC brodadcast quite a lot of radio drama using a technique which had a similar effect. You had to listen on headphones. I can't remember what they called it, but I'm fairly sure it wasn't 'Holophonics'. I seem to remember it working pretty well, I'd be interested to know if it was the same technique, Alan
ecphssrw@bob.csun.edu (Stephen Walton) (03/24/89)
[Note I edited both the Newsgroups: and the Followup-To: lines.] In article <580@serene.UUCP>, gbell@pnet12 (Greg Bell) writes: > Ever heard of Holophonics? Pioneered by a company called Zuccarelli >Holophonics. They have a demo cassette tape for $15 that is FASCINATING. On >a good tape deck, with headphones, the effect is amazing. The technique is called binaural sound. The recordings are made by placing small microphones inside a dummy head near the eardrums' location. They can be quite amazing. NPR broadcast a radio drama one or two Haloweens ago which used the technique. The trouble is, it sounds quite strange through speakers, mainly due to the odd frequency balance. -- Stephen Walton, Dept. of Physics & Astronomy, Cal State Univ. Northridge RCKG01M@CALSTATE.BITNET ecphssrw@afws.csun.edu swalton@solar.stanford.edu ...!csun!afws.csun.edu!ecphssrw
myers@hpfcdj.HP.COM (Bob Myers) (03/24/89)
>Yes, I read a sci-fi story about the noise eater also. It was in >"Tales of the Whitehorn" I believe (read it in high school). The >story was about the Fulton Silencer. If you like this idea you'll I think, if anyone's interested in looking this up, that it's actually from the collection "Tales From The White Hart", by Arthur C. Clarke. The "White Hart" was a pub in which the stories are told by a patron with a fine reputation for tall tales. Bob Myers KC0EW HP Graphics Tech. Div.| Opinions expressed here are not Ft. Collins, Colorado | those of my employer or any other {the known universe}!hplabs!hpfcla!myers | sentient life-form on this planet.