RME Audio ADI-2 Pro, User Manual

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User’s Guide ADI-2/4 Pro SE – v 1.0
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19.3 DSD Record
The ADI-2/4 Pro SE converts the analog input data not only to PCM, but optionally also to DSD.
Via
I/O - Analog Input - AD Conversion the AD-converter can be switched from PCM (Default) to
DSD. Based on the current mode the DSD data are then sent to the outputs AES and SPDIF
(DoP), USB (DoP via ASIO or ASIO native), and the analog outputs 1/2 and 3/4 (re-converted by
the DAC).
All modes, routings, source options and block diagrams of chapter 17 are valid for the DSD oper-
ation 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 of all channels are temporarily
disabled, even when transmitting PCM. This is signalled in several menus by brackets around the
(ON).
Please also note that the option
Digital Out Source set to Mains Out naturally disables the digital
outputs for DSD playback, as Mains Out is a DSP-processed PCM signal
– which doesn’t exist
during a DSD playback.
A mixed operation is possible. During a DSD recording, also AD conversion, a PCM file can be
played back and monitored via DA. Even a playback of DSD via channels 1/2 and simultaneous
monitoring of AES or Analog In via output 3/4 is possible, no matter whether the sources are PCM
or DSD.
Limitations exist, but they are identical with PCM and DSD. For example the limit of 192 kHz on
the digital I/Os AES and SPDIF means that in mode AD/DA only DSD64 can be used, not DSD128
and DSD256. That's not different to PCM, where the higher sample rates 384 and 768 kHz can't
be used. And the common clock does not allow any combination of modes. For example a re-
cording done at DSD64 (176.4 kHz) does not allow a simultaneous playback of 192 kHz; again
the same limitation applies in PCM mode.
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
19.4 DSD Level Meter
While most DACs, even ones seen as 'Hi-End', leave the
user clueless during DSD operation, the ADI-2/4 Pro SE con-
tinues 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 con-
version.
This additional conversion is not available for the digital I/Os,
shown in the Global Level Meter. Here DSD is shown as it
appears and sounds: with DoP as constant noise at about -
24 dBFS.