RME Audio ADI-2 DAC, Руководство пользователя

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32 User’s Guide ADI-2 DAC © RME
17.3 DSD Playback
While most DACs, even ones seen as 'Hi-End', leave the
user clueless during DSD operation, the ADI-2 DAC
continues to show level as well as spectral content. To be
able to show the analog I/Os audio signals on level meters
and Analyzer the DSP performs an additional DSD to PCM
conversion.
Analyzer and level meter show DSD signals in blue color,
the current mode is therefore easy to recognize.
During a DSD playback all DSP functions of all channels are temporarily disabled, even when
transmitting PCM. This is signalled in several menus by brackets around the (ON) and greyed-
out menu entries. An exception is the function
Polarity
, which stays available for one and both
channels.
Note: The change between PCM and DSD causes a low volume click noise. For optimized
sound and fidelity, the ADI-2 DAC does not use any lossy analog volume control, hence can't
suppress the DAC's low level click noise.
You may notice clicks and cracks at the title change quite often with DSD, even when the next
title has the exact same sample rate. This is caused by the 1-bit format, which, unlike PCM,
requires absolute silence and DC freedom at the beginning and end of a title, so that the
transition as required by the 1-bit stream does not represent a random signal, which can sound
like a click or crack. Unfortunately, many freely available tracks are not 'clean' at the beginning
and the end. If these are played back one after the other by player software, the ADI-2 DAC's
level meters show that the noise to be heard does not originate from the ADI-2 DAC, but is
presented to the DAC as a signal to be played. The level meters are in the digital domain before
the DAC, so proof of a faulty input signal is easy.
17.4 DSD Record
Via USB the SPDIF inputs can record not only PCM but also DSD (DoP).
The source options and block diagram in chapter 31.16 are valid for DSD operation as well, with
both record and playback. The only difference: with DSD the circuit part
DSP
is bypassed (no
audio processing). In DSD mode all DSP functions are temporarily disabled. This is signalled in
several menus by brackets around the (ON).
Software to record DSD audio:
Name OS URL
VinylStudio Win/Mac www.alpinesoft.co.uk
Sound-It! Win/Mac http://www.ssw.co.jp
Pyramix Win www.merging.com
AudioGate4 Win/Mac www.korg.com