| Video Noise March 2002
 The
Onkyo TX-DS989 A/V Receiver Upgrade -- Part Two
In January
we examined the Onkyo TX-DS989 upgrade process. Major components of the upgrade include
Dolby Pro Logic II and DTS Neo:6. The upgrade went smooth, but now it’s time to see
what benefits you actually get from these new toys.
Dolby Pro Logic advances
Original Dolby Pro Logic was an analog decoding process. It
relied upon a stereo signal being encoded with phase-altered sound according to Dolby
Labs’ specifications. The phase-shifted sound would then be decoded into four
channels: front left and right, center, and one rear-surround signal sent to both surround
speakers.
With the advent of digital A/V receivers and processors,
Pro Logic became a digital process. It relied upon the digital signal to produce the same
four-channel sound as the analog version. Digital versions of Pro Logic typically
integrate with the receiver or surround processor’s bass management, meaning the LFE
subwoofer is used to reinforce bass. This was not a feature of the original analog Pro
Logic.
The recently introduced Dolby Pro Logic II goes further.
The format is said to put discrete left and right sounds in the surround speakers. This
makes it a 5.1-channel surround format. The receiver/processor’s bass management is
used as well. Pro Logic II will properly decode Pro Logic sources, but it extends its role
by also being designed to turn stereo sources into 5.1 surround sound without those
sources having to be encoded in any way. It wasn’t possible to have a single Pro
Logic II mode that would do movies and music properly, so Pro Logic II has separate modes
for each: Movie and Music modes.
Dolby Pro Logic and Pro Logic II
Dolby Pro Logic laserdiscs like Braveheart, Jurassic
Park, and Pulp Fiction were enjoyable and involving when using Pro Logic,
though bass was noticeably limited compared to Dolby Digital or DTS versions of the same
soundtrack. The sense of envelopment wasn’t quite as convincing with Pro Logic as
with a discrete 5.1 mode, though ambient effects like crickets were almost as good as the
Dolby Digital or DTS experience.
On unencoded material, the original Pro Logic would deliver
frequent level mismatches in the rear surrounds. Besides the level problems, sounds would
jump unexpectedly from front to rear and back to front. It didn’t take long to become
annoyed with that listening experience.
Pro Logic II Movie mode, using the same laserdisc movies,
produced a listening experience that was much closer to Dolby Digital or DTS 5.1. Bass was
stronger and closer to the Dolby Digital or DTS versions of the same soundtracks. There
were occasional effects in either the right- or left-surround speaker only. Surround
effects were fairly subtle, a good thing since you are not distracted by too many sounds
being routed to one of the rear speakers. Pro Logic II seemed to be consistent in its
presentation. There were never questionable perspectives or direction changes that
didn’t match the screen action.
The movie sound of Pro Logic II was somewhat fuller and
richer than original Pro Logic, perhaps because of the apparent improvement in bass
extension. I found that unencoded drama and comedy were better in Movie mode, but
unencoded music performances were always better in Music mode.
Music mode of Pro Logic II was in a whole different league
compared to using the original Pro Logic for stereo music. Gone were all the inappropriate
shifts in sound and odd sound levels coming from the rear speakers. With Pro Logic II
Music mode you get a consistent surround effect that is more subtle than obvious. Pro
Logic II Music mode generally kept ambience in the back of the room and the performers in
the front -- the most natural music-surround presentation for most people. The center
channel is used less in Music mode compared to Movie mode.
For low- to mid-priced 5.1 speaker arrays Pro Logic II
produces a soundstage that is as impressively large as the best audiophile stereo
speakers, something the main stereo pair of speakers in the typical home-theater setup
could never do on their own. For many music-loving home-theater enthusiasts, Pro Logic II
Music mode has definite possibilities for making music sound fuller and more expansive
without becoming unnatural, colored, or unbalanced in the process.
Pro Logic II suffered a bit from having the analog output
of the laserdisc player converted to digital in the Onkyo TX-DS989, processed, then
converted back to analog. There was a very slight loss of articulation and clarity, but
that was offset by having a better sense of surround and much better bass than what had
been produced by the original Pro Logic. The loss of sound quality was especially minute
after the Onkyo upgrade since the TX-DS989 could then do the conversion from analog to
96kHz/24-bit resolution. If you use Pro Logic II with a digital source, the sound will be
better because the A/D and D/A loop would be unnecessary.
Dolby Pro Logic II vs. DTS Neo:6
While Dolby Pro Logic II has Movie and Music
modes, DTS Neo:6 has Cinema and Music modes. I found the sound of both to be
surprisingly similar. But DTS Neo:6 has one advantage. It produces 6.1 channels from
unencoded stereo sources. If you have center-surround speakers, DTS Neo:6 will put some of
the sound behind you. With the center-surround pair active in my system, DTS Neo:6 was
indeed more enveloping and seamless in the surround field than Pro Logic II.
Like Pro Logic II Music mode, DTS Neo:6 Music mode tends to
be more minimalist than spectacular. Performers stay up front and ambience and space is
expanded without the surround channels becoming obvious. I have a marginal preference for
the DTS Neo:6 format over Pro Logic II’s sonics. DTS Neo:6 Music mode seemed to have
just a bit more sparkle and transparency. DTS Neo:6 Music mode pulled further ahead of Pro
Logic II Music mode with the subtle enhancement of the center-surround fill-in. Like Pro
Logic II Music, DTS Neo:6 Music uses the center channel less than Movie/Cinema mode.
Comparing the Pro Logic II Movie mode to the DTS Neo:6
Cinema mode produces the same slight favoring of DTS Neo:6 for the same reasons, which
include slightly more sparkle and transparency and the center-surround fill. Both systems
share in making Dolby Pro Logic-encoded movies sound more like what you are used to
hearing from Dolby Digital and DTS.
When things go bump in the dark
Both Pro Logic II and DTS Neo:6 Music modes would produce
discrete sounds in the surround channels when the recording was engineered with
phase-induced effects. Recordings like Madonna’s two recent CDs, Music
[Maverick47598], and Ray of Light [Maverick 46847], have quite a bit of
altered-phase and placement information. These become interesting sonic events when
processed by Pro Logic II or DTS Neo:6.
All three laserdiscs used for the evaluation of Pro Logic
II Movie and DTS Neo:6 Cinema modes clearly produced discrete sounds in the surround
channels. But these events tended to be spaced-out through the movie rather than frequent.
Most people will probably prefer that, long term. Too much activity in the surround
channels would be distracting once you got over the novelty. The more aggressive logic
that would be required to put more discrete sounds into the surround channels would likely
make more mistakes than the conservative model adopted by Pro Logic II and DTS Neo:6. I
did not detect any discrete sounds that seemed incorrectly placed or inappropriate.
Bottom line
I liked my time with the Onkyo TX-DS989 and its
implementation of Pro Logic II and DTS Neo:6. Neither will replace high-quality stereo
systems with great loudspeakers, advanced digital sources, great preamps and amps, and
loads of good cables and accessories. But both extend the capability of low- to mid-priced
5.1 speaker systems to make music listening on those systems more entertaining.
If you have a library of Dolby Pro Logic movies, Pro Logic
II and DTS Neo:6 will make those movies sound better than original Pro Logic, regardless
of the performance level of your home theater. I could find absolutely no drawbacks to Pro
Logic II Movie or DTS Neo:6 Cinema modes when viewing Pro Logic-encoded movies.
Pro Logic II and DTS Neo:6 aren’t the sonic equal of
surround formats like DVD-Audio or multichannel SACD, but they aren’t meant to be.
They have the less ambitious role of expanding the music- and movie-reproduction
capability of many home-theater systems, and I believe they accomplish that goal. If you
have stereo sources you think you’d enjoy more in discrete surround, Pro Logic II or
DTS Neo:6 deliver the goods as long as your expectations are within reason.
Was it worth it?
In this case, the Onkyo TX-DS989 upgrade was an unqualified
success. The cost was modest, and the procedure itself was within the capability of most
people. The new features are all perfectly integrated with the original product -- they
are useful and glitch-free. That’s about all you could ask for in an upgradeable
component. And with the added performance, what more could one want?
...Doug Blackburn
db@hometheatersound.com |
