Creating The 16-Bit Hdcd Release Sound You Want; Hdcd16-Bit Amplitude Encoding & Dither Options; Peak Extension & Hdcd Limiting - Pacific Microsonics HDCD Model Two User Manual

Setup & Operation
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Model Two HDCD User's Manual

Creating the 16-bit HDCD Release Sound You Want

During HDCD 16-bit A/D conversion, or after HDCD 24-bit or 20-bit A/D conversion and 24-
bit or 20-bit digital processing, the Model Two's HDCD 16-bit amplitude encoding options,
Peak Extension, HDCD Limiting, Low Level Extension, and HDCD 16-bit Dithers, are used to
produce the best possible 16-bit HDCD encoded release masters from an analog or 24-bit
or 20-bit source. When used correctly, these options allow the Model Two to accurately
preserve the sound of different sources for both 16-bit undecoded and HDCD 16-bit de-
coded playback, whether they have wide dynamic range with infrequent short duration
peaks, such as most classical music or jazz, or are compressed or hard edged with little
dynamic range, typical of a lot of pop and rock.
Detailed descriptions of the amplitude encoding and dither options follow below, after
which there are suggested operating techniques for both limited and wide dynamic range
source material.
HDCD 16-bit Amplitude Encoding and Dither Options
Note: The menu selections to access an option, starting from the Operating Menu, are
shown in (parentheses).
Peak Extension & HDCD Limiting
For Peak Extension, from the Operating Menu select (OPS 2/PEAKEXT/ON). For HDCD Lim-
iting, select (OPS 2/PEAKEXT/LIMIT).
Peak Extension is a restorable (with HDCD decoding) soft peak limiter that allows peak
levels up to 6 dB above standard full scale level (+6 dBfs) on HDCD 16-bit recordings
without generating "overs". The limiter has a carefully crafted "easy-over" curve, designed
to mimic the sound of analog tape saturation that operates over an input signal level
range of -3 dBfs to +6 dBfs, in effect squeezing the top 9 dB of the input signal's range
into the top 3 dB of the 16-bit recording.
During HDCD 16-bit decoded playback, Peak Extension peak limiting is undone by the
HDCD decoder using a precisely mapped inverse of the limiting curve controlled by the
hidden LSB code, and the dynamics of the original material are restored up to +6 dBfs, thus
extending dynamic range by up to 6 dB.
HDCD Limiting functions exactly the same as Peak Extension during recording, except that
during playback the limiting curve is not undone with HDCD decoding. During HDCD de-
coded playback, HDCD Limiting has the same effect as during undecoded playback.
Use of Peak Extension or HDCD Limiting is optional in the HDCD 16-bit encoding process.
P A C I F I C M I C R O S O N I C S I N C .
Rev. C - January 2002
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