Written by 6:46 am Digital

DSD and PCM – Horses for Courses

Which is best, DSD or PCM? How about neither?


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Lately audiophiles have been hearing a lot about DSD, both
pro and con. Some record labels, such as AIX Records
, who’ve been
recording in high-definition PCM for years, see DSD as a competitor to PCM and
have posted a articles stressing DSD’s shortcomings
. I think this is a giant waste of time and effort.

No recording medium is without intrinsic issues that limit
fidelity. Whether it’s analog tape’s tape scrap flutter, or vinyl record’s off-center
pressings, record warp, limited S/N, PCM digital’s timing, sampling and quantization errors, or DSD’s spurious noise at extreme upper frequencies and limited editing
capabilities, no media is perfect. The recording engineer’s ultimate goal isn’t to enumerate each
medium’s problems, it’s to work around those problems to achieve the best sonic
results.

PCM and DSD should and can co-exist in the modern world. Each
has certain advantages over the other, primarily based on what they do best.
DSD is the best way to archive analog recordings if you need maximum
flexibility to release in different digital formats. DSD can be converted
easily, without decimation errors into any PCM sample and bit rate. PCM is not
so flexible.

In the early days of digital recording the only commercial
release format was redbook CDs at 44.1/16. Whatever recording medium an
engineer used, it would eventually have to be converted to CD. While 88.2 kHz
easily converts to 44.1 kHz, 96 kHz does not decimate cleanly, generating
rounding errors that effect fidelity. Some engineers, such as Stereophile’s
John Atkinson, recorded at 88.1 instead of 96
 kHz to avoid that issue. Nowadays digital files can be recorded and released at
any PCM format from lowly 128 BPS MP3 all the way up to 192/24 (yes, 384/32 is
a possibility, but not yet commercially realized).

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It has gotten to the point that an engineer can choose the
sample-rate and bit-rate for a PCM project based on workflow and fidelity rather
than final format considerations because any recording can be released in its “native”
or original format. If a recording is made at 96/24, it can be released at
96/24. If a recording is made originally in DSD, in can be released in DSD.
There’s no reason to convert a high resolution PCM file into DSD or convert a
DSD file to PCM for final release. Native rate rules.

If a project requires multi-tracking, dubbing, and EQ
corrections, PCM is a far better recording choice than DSD. When I record my
bluegrass band we use PCM, click-tracks, and multi-tracking because, frankly,
we’re not good enough to do an entire song in one take perfectly. Many bands
are in a similar position. Other reasons for using PCM include recording
situations where instruments can’t be recorded all in one take such as when a
drum track is needed behind an acoustic guitar. Drums are so much louder that
they bleed into the guitar’s microphones, which requires either isolating the
drums (sometimes in another room in the studio) or forcing the drummer to play
at unnaturally low levels.

DSD is best for live recordings of acoustic concerts. If you
only need two tracks, plan to mix down (if needed) real-time and don’t need to
use any overdubs or additional tracks, DSD is the way to go, in my humble
opinion. I’ve been using DSD for live classical concert recordings since
November 2007. With DSD I can easily generate a 44.1/16 version as well as
96/24 and 192/24 files. With even the simple the editing program AudioGate I
can do edits, fade-ins and fade-outs, and all my PCM conversions (if I need to).

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PCM and DSD are different and I believe complementary
recording methodologies. Smart audio engineers and producers must consider both
before choosing one or the other for a recording project.

Perpetrating the idea that either DSD or PCM are technically
“better” than one another is a waste of intellectual horsepower. The debate
should be how to use each format to achieve the best sonic results. If less
time was spent elucidating format issues and more time finding solutions that
best utilize current recording methods, the results would be better recordings
and less time wasted championing things that don’t need champions.

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