FWD: On MiniDisc and DAT


Subject: FWD: On MiniDisc and DAT
From: KEVIN AUSTIN (KAUSTIN@vax2.concordia.ca)
Date: Fri Jan 22 1999 - 04:16:05 EST


Sorry for doubles.

FYI: This is a re-posting of some comments from the AUDITORY list, regarding
MiniDisc and DAT comparison / uses.

Kevin Austin
kaustin@vax2.concordia.ca
CECDISCUSS List Administrator

Vous pouvez ecrire en francais ou en anglais.
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

From: IN%"AUDITORY@LISTS.MCGILL.CA" "AUDITORY Research in Auditory
Perception" 22-JAN-1999 00:03:23.94

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Date: Thu, 21 Jan 1999 14:16:28 +0000
From: Christel de Bruijn <c.bruijn@DCS.SHEF.AC.UK>
Subject: mini-disk or DAT?

Dear list,

I'm about to start a series of experiments on voice quality, and am
planning to use a portable mini-disk recorder to record speech from
subjects with. Afterwards I intend to carry out some acoustic analysis on
the speech samples, including harmonic-to-noise ratios and jitter and
shimmer measurements, among other things.

However, it has been brought to my attention that, if one wants to do
acoustic analysis on the recorded speech, it may be preferable to use a
DAT-recorder instead.

I am aware that this is an auditory list, but thought that people would
most probably know about this anyway. I would appreciate it very much if
anybody could explain any pro's and cons of using a mini-disk or DAT
recorder.

Thank you very much in advance,

                             Christel de Bruijn
                             Department of Human Communication Sciences
                             University of Sheffield, UK

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Date: Thu, 21 Jan 1999 09:38:36 -0600
From: Sheila Williams <williams@PSYVAX.PSY.UTEXAS.EDU>
Subject: Re: mini-disk or DAT?

Dear list,

I would like to thank everyone for the information and comments they sent
me for my enquiries on Minidisk vs. DAT and will give a brief summary here
in response to Christel's enquiry.

There was a lot of information so I may be able to post a more complete
summary later.

Apologies in advance if I may have misunderstood any of the
comments/technical information.

The overall response to my enquiry was a resounding - Minidisk is good for
recording things to be listened to as it gives high perceptual quality and
long-lasting recordings.

However, and this is a BIG one, in order to avoid use for copying
commercial recordings, Minidisk technology incorporates input filtering
and data compression strategies deliberately designed to distort the
signal in subtle ways which makes the signal more difficult to analyse and
impossible to make accurate measurements of - it also leads to perceptible
distortion if multiple copies are made, so DAT is much better for accurate
measurement.

DATs mostly (or all) come with the ability to switch off any such
compression factors. However, tape media is less robust so should be
archived.

Advice on microphones included use of "cardioid" microphones to get a
general directional background filtering effect without the need for
precise directionality and to use headset mics to maintain distance (to
ensure any amplitude fluctuations are due to the speaker and not the
distnace).

There are devices out there for converting from optical to coax
input/output for data trandfer. Decks for rack-mounting seem more likely
to have coax digital ports already, avoiding the need for these devices.

thanks again for all the advice. For our purposes, which include analysis
and resynthesis of speech recordings, we will definitely be going with DAT
and I am now investigating the relative costs/benefits of the different
systems currently available before we choose our set-up.

I'll try to provide a more technical summary (and a list of all the
contributors), including a comparison of the different systems I can find,
when I've had the chance to wade through all the technical data.

Sheila

Dr Sheila M Williams phone: 512-471-4253
Psychology, University of Texas at Austin lab: 512-471-0693
528 Mezes Hall, Austin, Texas, USA, 78712 fax: 512-471-6175

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Date: Thu, 21 Jan 1999 11:03:02 -0500
From: "Richard J. Fabbri" <fabbri@NETAXIS.COM>
Subject: Mini-Disk or DAT?

Dear Christel,

The main difference between Mini-Disk and DAT goes beyond the clear
difference in recording media (Disk versus Tape) ... you might include
the DCC (Digital Compact Cassette) too, as it is quite similar to Mini-Disk
preprocessing of audio information.

DAT is a true (linear) sampling recorder that acquires and stores 16-bit
Stereo samples. I personally own and use a DAT (Sony TCD-D3).
The recording technology of DAT is essentially identical to the common,
commercial Compact Disk. In fact, you can copy an audio CD on DAT
with the digital optical fiber cable supplied with DAT !

The Mini-Disk (and DCC) are truly ingenious in that they each
post-process their digital samples for frequency/amplitude content
and perform a detailed Masking assessment so as to record only
those frequency components our hearing can "perceive" ... thus, a
Real-Time, Psychoacoustic Masking analysis of live audio is done
in these tiny (technological marvels!) recorders ... subsequent
recording on the Mini-Disk (or, DCC tape cassette) records only the
"perceivable" frequencies we "hear". The commercial goal of this
amazing technology was to produce a small ("mini" disk) or
inexpensive (DCC) medium to record Hi-Fi Stereo.

Thus, be aware that much of the stereo microphone wave form will
not be recorded on either a Mini-Disk or DCC !

Your goal is to (post) analyze audio recordings for:
        1) Harmonic-to-Noise ratios
        2) Jitter
        3) Shimmer.

But, Mini-Disk or DCC purposely avoids recording much of the Stereo
waveform so as to reduce the subsequent data storage necessary for
Hi-Fi Stereo playback. Thus, the Stereo data you wish to capture is
probably missing in a Mini-Disk or DCC recording.

DAT is a portable, 16-bit audio, linear sampling recording technology.
DAT simply records Stereo waveforms as 16-bit samples.

Best Regards,
Rich Fabbri

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End of AUDITORY Digest - 20 Jan 1999 to 21 Jan 1999 (#1999-9)
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end of fwd

ka



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