| Video Noise January 2005
Getting the Most from a
DVD-Audio Player’s 24/192 D/A Conversion
You may have recently replaced your aging DVD player with a
newer model capable of playing DVD-Audio discs in addition to DVD-Video discs and music
CDs. If you have, that means that your new player has 24-bit/192kHz digital-to-analog
converters -- which the DVD-A standard requires -- instead of your old player’s
24-bit/96kHz DACs. This higher operating frequency makes possible gentler digital and
analog filters that will improve the sound of digital even when you aren’t using the
new DACs’ full 192kHz bandwidth.
Most new DVD-A and DVD-V players have so many playback
modes that you should think seriously about changes you can make to your system that might
result in better sound. When you’re listening to DVD-A content, you must use the
5.1-channel analog outputs, because that’s the only output mode now available for
DVD-A. Some manufacturers do provide nonstandard proprietary digital connections, but only
when you use their DVD players and receivers together.
When listening to movie sound or DTS music discs, you can
use the player’s 5.1 analog outputs or the digital output connection, coaxial or
optical. Let’s dispense with the optical output first: It has been my experience that
the inexpensive TosLink connection never sounds as transparent as a digital coaxial
connection.
About those digital coax connections: If your outboard
stereo DAC, surround processor, or receiver uses 24/96 DACs, a new DVD-V or DVD-A/V player
with 24/192 DACs might sound better through its 5.1 analog outputs. These will make use of
the player’s 24/192 DACs, while the digital coax connection will use the 24/96 DACs
in the outboard DAC, surround processor, or receiver.
A DVD player’s cost is no indicator of whether it will
sound better than your outboard DAC, surround processor, or receiver. An inexpensive DVD
player can sound ridiculously good when used as a CD transport to send the signal
to an outboard DAC and jitter-reduction device, in combination with high-quality
interconnects and power conditioning.
Using a DVD player’s multichannel outputs
 Because you
might now be using your processor or receiver’s multichannel inputs for the first
time, it’s vital to set up the system correctly before doing any critical comparisons
of analog vs. digital connections. If the output levels of the DVD player’s 5.1
analog outputs can be set internally, that will probably be much easier than using the
receiver or surround processor’s setup for its multichannel inputs.
Most processors and receivers cannot generate an analog
pink-noise signal to balance their multichannel inputs. Instead, they generate digital
pink noise to set the balance of all 5.1 channels. If your processor or receiver is one of
these, you’ll need a test or setup DVD with 5.1-channel setup tones. Both the Avia
Guide to Home Theater DVD and Joe Kane’s Digital Video Essentials have
these.
Play the test tones for each channel, noting on paper the
readings, in decibels, from your sound-pressure-level meter. Decide how many dB need to be
added to or subtracted from each channel to balance all 5.1 of them. Use the setup menu in
your processor or receiver or DVD player to make those adjustments. Then play the
5.1 test tones again to confirm that all channels have the same output levels. If the
levels are still not perfectly matched, repeat this procedure until they are.
Shoot-out reference discs
Once the channel balance is correct for the multichannel
connection between the DVD player and receiver or surround processor, you can begin your
evaluation of which sounds better decoding Dolby Digital and DTS. Many people won’t
have anything other than movie soundtracks to use as references, but some of the faint
details you’ll want to listen for may be lost in the bombast of a loud film
soundtrack. A good-sounding music DVD would be a better choice.
 The best choice would be
one of the DTS 5.1 CDs released by DTS Entertainment and in limited numbers by a few other
labels. All of these were released before the advent of DVD-Audio and SACD. While most DTS
reissues of older titles from the 1960s and 1970s have poor fidelity due to the quality of
the master tapes, some of those mastered from newer recordings sound fairly good, though
they won’t challenge DVD-A in absolute fidelity. I found the DTS 5.1 release of Alan
Parson’s On Air an invaluable tool for determining whether my DVD-A player or
processor or receiver sounded better decoding 5.1-channel recordings.
Don’t assume that a cheap DVD player’s
5.1-channel decoding can’t exceed that of much more expensive receivers or surround
processors -- a $120 Pioneer SACD/DVD-A/V player sounded more transparent in my system
than a 24/96 receiver that sold for 20 times as much! Of course, you’ll need very
good analog interconnects before that can happen -- and I felt sort of silly with almost
$1500 worth of analog interconnects connected to a $120 DVD player. I haven’t yet
held a shoot-out with $120 worth of analog interconnects instead of the premium-priced
jobs, but it would be worth a try.
...Doug Blackburn
db@hometheatersound.com |
