nivek@rover.ri.cmu.edu (Kevin Dowling) (09/28/87)
Recent posts on sending digital signals to speakers are not that far fetched. I envision speakers of the near future where only digital signals are sent to each speaker. Digital filtering for crossover networks might minimize overlap of frequency bands going to different drivers. By keeping all 'adjustments' (balance, tone, equalization etc) in the digital domain it will perhaps lend itself to more precise (i.e. better) control over the eventual sound without coloration from various analog stages. Of course, interconnections for these new systems might be a hard sell, but it may begin with amplifier units that accept digital and do a D/A only at the final stage where speaker connects occur then later progressing to (nearly) all digital systems. - Does someone have a pointer to a digital speaker system that was developed at MIT (?). I'm not sure but it may have used phased-array techniques to generate the output. nivek Aka : Kevin Dowling Bell: (412) 268-8830 Arpa: nivek@rover.ri.cmu.edu Mail: Robotics Institute Carnegie Mellon University Pgh, PA 15213-3890
larry@kitty.UUCP (Larry Lippman) (09/29/87)
In article <1041@rover.ri.cmu.edu>, nivek@rover.ri.cmu.edu (Kevin Dowling) writes: > Recent posts on sending digital signals to speakers are not that far fetched. > I envision speakers of the near future where only digital signals are sent > to each speaker. > ... > - Does someone have a pointer to a digital speaker system that was developed > at MIT (?). I'm not sure but it may have used phased-array techniques to > generate the output. I don't know anything about this phased-array technique, but I recall that a patent was issued and assigned to Bell Laboratories in the early 70's concerning a true digital acoustic transducer. This transducer had concentric sections of increasing surface area. Each section was individually driven, either through piezoelectric or electrodynamic means. Each section increased in area by a digital weighting on the order of 1-2-4-8 etc. I had some reference material on this transducer, with was either a copy of the patent or a Bell System Technical Journal article, but I cannot locate it at the moment. I believe the orignal intent of the device was for use as a telephone handset receiver, but the design would lend itself to loudspeakers. Obviously, this might be the ultimate in digital sound reproduction, if it is practicable. Anyone know any more about this device? <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
jimm@mitsumi.UUCP (09/30/87)
In article <1041@rover.ri.cmu.edu> nivek@rover.ri.cmu.edu (Kevin Dowling) writes:
)Recent posts on sending digital signals to speakers are not that far fetched.
)I envision speakers of the near future where only digital signals are sent
)to each speaker. [...]
)
)Of course, interconnections for these new systems might be a hard sell, [...]
)nivek
Interestingly, there is a standard not only for the format of a digital music
signal, but I was pleasantly surprised to learn (and see, at CES) that
there is also a standard for a fiber-optic connector, as used in connecting
CD's and R-DATs together (yep i know the sampling rates differ, but you
can go A/D and back in the R-DAT (i think) and you can hook R-DATs together).
There is even a preamp from Kenwood that has digital input (I don't know if
it has optical or RCA connector, or both) but I was told it goes D/A right
away (before any frequency domain processing).
The format standard, authored by Sony, I believe, includes a few "reserved"
fields which may be suitable or intended for information in the system you
describe, such as volume specification.
jimm
--
Jim Mackraz
Mitsumi Technology, Inc. 408/980-5422
{amiga,pyramid}!mitsumi!jimm