Xref: utzoo rec.music.synth:10835 comp.music:595 comp.dsp:442
Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!munnari.oz.au!csc!csc3!arp!hc
From: hc@arp.anu.oz.au (Hugh Clapin)
Newsgroups: rec.music.synth,comp.music,comp.dsp
Subject: Re: Ariel Digital Microphone
Message-ID: <1990Jan12.001755.243@arp.anu.oz.au>
Date: 12 Jan 90 00:17:55 GMT
References: <4390@rayssdb.ray.com>
Organization: Automated Reasoning Project, ANU, Australia
Lines: 45

From article <4390@rayssdb.ray.com>, by iws@rayssdb.ray.com (Ihor W. Slabicky):
> In article <7471@pt.cs.cmu.edu>, agn@unh.cs.cmu.edu (Andreas Nowatzyk) writes:
> 
>> BUT, it you use the build-in microphone elements... They use 2 plain
>> electret pressure capsules side by side in a block of foam! Similar to the
>> 50cent Radio-Shack special. Channel separation is about nil, and the
>> overall quality is marginally better than a telephone. It is really a very
>> odd device: state of the art electronics with sub-consumer grade acoustics.
> 
> 
> ... excerpted from TV Technology, November 1989 issue ...
> 
> A special version of the Ariel Digital Microphone, which can only
> be used with the NeXT Computer System is on sale now for $595.
> The Model DM-N has two electret condenser capsules in an x/y
> configuration to pick up analog sounds in stereo.  Two 56ADC chips
> convert the analog signals to digital format.  The device has a
> dynamic range of up to 92 dB with a total harmonic distortion of
> 0.005 percent.  


Just a note of clarification (I know nothing about this device other
than what's been posted here) - the `device' in question in the press
release could *only* refer to the d-a, not to the whole system, capsule
and all. If the actual microphone capsules are anything like as bad as
is
indicated by the first poster, then THD would be far above 0.005% . I
have no figures but I would guess a Radio Shack cheapy mic would have a
THD in the order of 0.5-1% .

The idea of *good* mic with a built in d-a is interesting, however
probably unnecessary for most professional (and I would think
computer/sampling) applications. Mic level signal in any decent mic is
balanced, and thus rejection of noise, hum etc is pretty good. The advantage
of doing your d-a at mic level may be justified in some areas, but such
devices already exist as outboard units. 
The acoustics and electronics of building a good
microphone are probably much harder than accurate d-a and a-d. For most
professional applications you'd prefer to be sure of your microphone,
and risk the extra (tiny) amount of noise in a pre-amp than
put up with a sub-standard mic. I could see that it might be convenient
for  computer sampling applications where broadcast/recording standards
are not important.

hugh clapin