T+A HV Series, Руководство пользователя

Страница: 9 / 78

9
Introduction
PCM and DSD Two competing formats are available in the form of PCM and DSD, both of
which are used to store audio signals at very high resolution and quality.
Each of these formats has its own specific advantages. A vast amount has
been written about the relative merits of these two formats, and we have no
intention of participating in the dispute, much of which is less than objective
in nature. Instead we consider it our task to develop equipment which
reproduces both formats as effectively as possible, and exploits the
strengths of each system to the full.
Our many years of experience with both systems have clearly shown that
PCM and DSD cannot just be lumped together; it is essential to treat each
format separately, and take their specific requirements into account. This
applies both at the digital and analogue level.
For this reason the
SDV 3100 HV employs two separate digital sections, two
D/A converter sections and two analogue back-ends - each optimised for
one format.
SDV 3100 HV and DSD
By its nature the DSD format involves a noise floor which rises above the
range of human hearing as frequency rises. Although this noise floor is not
directly audible, it does subject the treble units in the loudspeakers to a
significant load. It is also possible for the high-frequency noise to cause
distortion in many low-bandwidth amplifiers.
The lower the DSD sampling rate, the more severe the inherent noise, and it
cannot be disregarded, especially with the DSD64 format - as used on the
SACD. As the DSD sampling rate rises, the high-frequency noise becomes
increasingly insignificant, and with DSD256, DSD512 and DSD1024 it is
virtually irrelevant. In the past it has been standard practice to apply digital
and analogue filtering processes in an attempt to reduce DSD noise, but
such solutions are never entirely without side-effects on sound quality. For
the
SDV 3100 HV we have developed two special techniques designed to
eliminate the sonic disadvantages:
1.) The

True-DSD technique, consisting of a direct digital signal path
without filtering and noise-shaping, plus our True 1-bit DSD D/A converter
2.) Analogue reconstruction filter with selectable bandwidth
The

True-DSD technique is available for DSD sampling rates from
DSD64 upwards.