Meridian America Digital Audio Processor Meridian 518 - Manual (Page 31)

Using 518 for Mastering and Multimedia 31
518 User Guide
Part 2
Mastering Processor
The Meridian 518 Digital Audio Processor has been designed to allow
the making of better recordings, and in particular to enable the
production of high-quality, enhanced-definition CDs.
The predominantly available channels for delivering high-quality sound
to consumers is stereo, linear-encoded 16 bit PCM. There is also no
realistic prospect of a widely-available improvement on this capability.
While CD is limited to 16 bits, we now have A/D converters, recorders
and editors operating with anywhere between 16 and 24 bit words.
The Meridian 518 provides the very best quality and combination of
signal-processing functions for use when preparing material for issue on
media like CD. In fact, using the unique signal processing in 518, CDs can
be produced with up to 19-bit subjective dynamic range.
The functions of 518 have been optimised for use in three stages of
the production process, namely:
•
on location, processing the signal between the A/D converter and
recorder,
•
during transfer of a recording to an editor,
•
during transfer from editor to production master.
In each such step, the word-size can be different, and 518 can make
these processes optimal.
The signal-processing used is based on an extensive programme of
research, and is implemented in DSP with an internal precision of 72
bits to ensure exceptional transparency. For a very full technical
background, please see the papers referred to below: copies may be
obtained from Meridian.
1 2 3 4
518 also finds applications in professional or consumer replay
situations. Here the precision gain control and pre/de-emphasis
processing can replace the system preamp and enhance the dynamic
range of a D/A converter – see the earlier sections of this manual.
1 J.R. Stuart and R.J. Wilson, "A Search for Efficient Dither for DSP
Applications", 92nd AES Convention, Vienna 1991, Preprint #3334
2 J.R. Stuart, "Noise: Methods for estimating Detectability and Threshold", 94th
AES Convention, Berlin 1993, Preprint #3477
3 M.A. Gerzon, P.G. Craven, J.R. Stuart, R.J. Wilson, "Psychoacoustic Noise-
Shaped Improvements to CD and other Linear Digital Media", 94th AES
Convention, Berlin 1993, Preprint #3501
4 J.R. Stuart and R.J. Wilson, "Dynamic Range Enhancement Using Noise-
Shaped Dither Applied to Signals With and Without Pre-emphasis", In
preparation for AES Convention, Amsterdam 1994.