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From: ti@altos86.Altos.COM (Ti Kan)
Newsgroups: rec.audio.high-end
Subject: Re: (very) Unconventional Speakers
Message-ID: <2700@uwm.edu>
Date: 2 Mar 90 14:03:57 GMT
Sender: news@uwm.edu
Lines: 31
Approved: tjk@csd4.csd.uwm.edu


In article <2678@uwm.edu> aipp@castle.edinburgh.ac.uk (Pavlos Papageorgiou) writes:
>	Has anybody out there investigated, or at least considered, the
>concept of a 'digital speaker'?  --- meaning a method for driving the
>cone in discrete steps. 
>	This might be accomplished by any means, from the rather banale
>of building a high-power ADC in the speaker box, through PWM, to fancier
>tricks like having multiple windings on the speaker coil (having 2, 4, 8
>etc.  loops), or having a feedback mechanism to sense the position of
>the cone and a computer to then generate the appropriate currents to
>move the cone smoothly to the next position. 
>	I know it's far off, but I think it makes sense.
>	All debate welcome :-) [Not bloody likely. -tjk]

I guess the question is *why*.  I don't think such a device will
provide any real performance advantage over the current amplifier/speaker
interface.  Going digital just for digital's sake is not what I call
sensible engineering!  Modern power amps typically have vanishingly
low noise and distortion, and has extremely wide bandwidth.  All the
problems that exist today in this setup are mostly in the speakers
(i.e. phase shift from the drivers and crossover network, distortion
from modulation and cone-flexing, power handling limitations, dispersion
anomalies, resonances, etc, etc.  None of which can be fixed by driving
the speaker digitally.

-Ti
-- 
Ti Kan                                                                  \\\
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