Studer d 820 mch brochure

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24 BIT RECORDING

EDR Extended Digital Resolution by STUDER

A 16 bit word resolution has become estab-
lished throughout the entire audio industry.

Why now 24 bit!

In 24 bit technology the original analog signal
can be recorded with a resolution that is 256
times more accurate than with 16 bit technology.

An analog signal basically has an infinite
resolution. 16 bits allow only 65,536 steps for
the approximation of the original signal. Not
even close to infinity! By contrast, 24 bits yield
a resolution of 16,777,216 steps.

From theory to practice

What are the advantages of 24 bit technology
when the original is possibly limited to an

18 bitA/D conversion or when the final playback
device is limited to 16 bit.

One significant advantage is the increased
signal-to-noise ratio resulting in a much larger
headroom without sacrificing resolution.

In most cases the recorded signal requires
further processing, mixing, frequency response
corrections, etc. ideally, these tasks should also
be performed in the digital domain to prevent
unavoidable losses in D/A - A/D conversion.
This work can be performed most conveniently
on a digital mixing console for which the
D827 MCH with the EDR option is the ideal
partner.

Modern signal processor architecture, such as
implemented in the STUDER D940 digital
mixing console, use a resolution of up to 56 bit
for all signal processing algorithms.

Why all the fuzz? A rule applicable to calculati-
ons with binary numbers states that the multi-

plication of two data words with the width «n»
(i.e. «n» bits) results in the word width «2n».
For example, when two 16 bit words are multi»
plied in a digital mixing console, the result
contains 32 bits.

The axiom is:

keep the resolution as high as possible. It is
desirable to maintain this higheresolution result
as long as possible because losses occur inevi-
tably in every conversion from a larger to a
smaller word length.

The word length should only be reduced to 16
bits in the final processing step, for example in
CD mastering.

Compatibility

A change to the DASH format does not make
any sense. Compatibility must be maintained
with the large installed base of over 1000
DASH multitrack machines.

How does the signal get
into the machine!

Access to the EDR processor is implemented
through the multichannel audio digital inter-
face, MADl (simultaneous for all tracks, co-
axial or fiber-optic) or the AES/EBU interface
for up to 2 tracks simultaneously. Both these
formats are already specified for 24 bit trans-
mission.

lo or 24 bits - selectable

With the push of a button recording and play-
back of 48 tracks in 16 bit mode, or 24 tracks
in 24 bit quality can be selected.

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The solution Is «Bitmapping»

Without modifying the DASH format, the EDR
option for the D827 MCH realizes linear 24 bit
recording of up to 24 channels. The data are
distributed on the tape in such a way that high-
order bits are recorded in the DASH format on
tracks 1 to 24, where as low~order bits are
recorded on tracks 25-48. There is a fixed track
relationship: track number B is always A+24.

One advantage of this allocation is that a tape
recorded in EDR mode can be played on a

standard DASH machine without any compati-
bility problems.The «A tracks» represent the
recording in 16 bit quality while the «B tracks»
are reproduced as «noise».

In orderto continually preserve 24 bit quality,
also during punch-in punch-out, cross»fades
must be calculated with 24 bit resolution by
the recorder. This task can only be performed with
internal solutions such as the STUDER EDR
processor.

n 2.

v 2x16bit 2X16bit
16 bit 16 bit
process process

g

24 bit
EDR - processing

U

U

24 bit MADl- or AES/EBU-lnterface

Regardless of whether you are producing in «conventional» analog technology using the STUDER
converters, or you want to record in 24 bit digital - or both -:

the STUDER D827 MCH is your ideal partner.

Technical Data

Channels for processing 24
Word resolution: 24 Bit
Allows to select between: 16 Bit 48 channels
and 24 Bit 24 channels
Accessible via: MADI (all 24 channels)
or AES/EBU interface (2 channels at a time)

STUDER

PROFESSIONAL AUDIO EQUIPMENT

H A Harman lnternational Company

Direct Subsidiaries:

Order Information

EDR installation kit 21 .863.666.20

Subject to change.

STUDER is a registered trade mark of STUDER Professional Audio AG
Printed in Switzerland 10.26.19301Ed. 0895]

Copyright by STUDER Prulessional Audio AG

STUDER Professional Audio AG, Althardstrasse 30, CH-8105 Regensdorl-Zurich
Switzerland, Telephone +41 1870 7511,Te|ei'ax +41 1840 47 37

Austria: +43 1 866 54-0
Germany: +49 30 72 39 34-0
UK: +44 (11 707 66 50 00

Canada: +1 416 51013 47
Japan: +81 3 34 65 22 11
Singapore:+65 481 56 88
USA: +1 615 39133 99