This article explores the potential benefits of new technologies used in
the reproduction of sound over the past decade, from stereo to DVD-Audio,
and how technologies can impact your enjoyment of classical music. With
these new technologies, audiophiles have more opportunities to enhance the
listening experience.
Over the past two years my home audio system has undergone a dramatic
transformation. As a result, I'm now rediscovering my CD collection.
I'm also uncovering some interesting new recordings that would not have
been available to me a year or two ago. Let me explain.
My interest in music has been life-long. I can remember hiding one of
those "pillow speakers" under my pillow every night when I was only eight
so I could listen to '60s "Top 40" radio. My mom likes to relate the story
that when I was a newborn and she was up with me at night, she couldn't
listen to music because even though I would get quiet, I wouldn't fall
asleep. Instead I appeared to be listening intently. (This also went
for TV - my head would loll back and she would think I had finally drifted
off to sleep, only to find I was watching TV upside-down; but that's
another story....)
My interest in the faithful reproduction of music is nearly as long-lived.
Though as a youth I had an assortment of record players and radios, I put
together my first real system when I was 15 (Marantz receiver and Thorens
turntable, both of which still work).
As soon as I got my driver's license, I proceeded to haunt stereo stores.
My budget was certainly limited to what can be found in the low/mid-fi
stereo stores in malls, but I lived near Atlanta, which also had a few
high-end audio stores and I spent hours talking to the salespeople and
checking out the latest equipment. This was circa 1973, and quadraphonic
sound (i.e., four channels of music instead of two) was all the rage.
Stereo was then 15 years old, and obviously in need of a facelift.
The solutions suffered as much from the immaturity of the technology as
they did from the numerous competing formats. Some technologies, such as
JVC's CD-4, CBS's SQ, Sansui's QS, Electro-Voice's EV-Matrix, Dynaquad, the
obscure RS Quadravox, and others, matrixed two additional channels of music
in with the existing two stereo channels. Usually, this was accomplished
through the modulation of the second pair of signals onto a supersonic
carrier, then onto the original media (typically a vinyl LP).
In addition, there was discrete quadraphonic (DQ) technology. DQ generally
existed only on tape, though the Nippon Columbia matrixed UD-4 LP format
was also considered "discrete." There were very few discrete quad tapes
available commercially, even at the peak of its popularity. None of these
formats played well with the others. In fact, they were all mutually
exclusive (though typically backwards-compatible with normal stereo). The
result was consumer confusion and eventually the idea of quadraphonic sound
would drift away for the time being.
Quadraphonic recordings made back then were often odd beasts sonicly,
meant as demonstrations of the capabilities of the surround sound system
through dramatic aural effects, rather than faithful reproductions of
real-life music venues. Sounds were often "ping-ponged" from front to
back, or rotated around the room. Similar games were played when stereo
was first introduced, bouncing an instrument from side to side for example.
Instruments were arbitrarily placed in surround speakers, putting the
listener inside the ensemble. Actually, you were lucky if your listening
perspective was stationary, as many times the viewpoint (hearpoint?) of
the listener would constantly shift with respect to the soundstage.
In any case, it was an interesting time, even if none of these technologies
caught on. I became heavily involved in classical music as the surround
sound fad was passing, so I had little listening experience with orchestral
and chamber music in anything other than stereo. As I've written before on
the list, my brother has a rather extravagant home theater setup (poking
into the low six figures), so I have had a chance to listen to a high-end
surround setup with my favorite recordings only during the last couple of
years. But I get ahead of myself.
Surround sound was not new in the early 70s. Filmmakers had experimented
with multi-channel soundtracks for decades. Disney's "Fantasia," released
in 1940, had discrete 6-channel sound, as did the Cinerama series of movies
in the 50s. There have been many other multi-channel cinema experiments.
Remember Sensurround (surround the audience with subwoofers, and shake
them in their seats)? Anyway, these systems were never practical for home
viewing.
As most of you are aware, multi-channel sound has made a comeback, and in
a big way. The first movie to use Dolby's Pro Logic technology in a way
that truly excited the pubic was the first Star Wars movie released in
1977. Dolby Pro Logic surround for TV and videotapes became common in the
late 1970s and early 1980s. Interestingly, Dolby Pro Logic is a modified
"full logic" version of the CBS's SQ quadraphonic format. Once again,
people began exploring multiple speaker setups in their home, this time to
watch videos, movies, and TV, but not primarily to listen to music. Music
videos and movies with Pro Logic soundtracks eventually became extremely
popular in the pop, rock, and country genres. This set the stage for more
recent advances in digital technology, introducing some fascinating
alternatives to stereo or quadraphonic sound.
So, what does all this have to do with classical music? Put another way,
what is so special about classical music? While I have a large pop/rock
collection that I visit and enjoy often, classical music is, in general,
much more sensitive to issues of sound staging, depth, imaging, balance,
and so on.
In classical music, it is important that a violin sounds like a violin.
If a person is standing in a room and playing a violin, a listener can tell
exactly from where the sound is emanating, how loud it is, and especially
how loud it should be with respect to the cellist who just entered the
room. Orchestral arrangements are specific: violins to the left (or
sometimes left and right), violas in the middle, cellos and basses to the
right, woodwinds in the center further back, and brass and percussion at
the far back. There are variations, of course, but in general the sound
image created by an orchestra is fairly standard.
Compare this to a rock band whose sound actually comes from amplifiers
and speakers spread around a stage or a studio. With an electric guitar
or especially a synthesizer, the combinations of loudness, timbre, tones,
and so on are nearly infinite. Therefore, in effect, there is no baseline
sound. Realism - as referenced by the original performance - is usually
not as important in popular music. After all, only those present at the
original recording session would know exactly what the instruments sounded
like on that occasion.
It is not nearly as important to be careful when preparing the surround
sound mix for a popular music release. A good example of this is the very
first rock band to play concerts in surround: Pink Floyd. These concerts
were famous for their "wall of sound" effect that immersed the audience in
the music. That a guitar sound was coming from all around instead of from
an easily identifiable location on a stage was not a problem. In fact, the
instruments might even be moving,
Conversely, it would be very disconcerting to hear a performance of a
Beethoven piano concerto with the piano solo coming from behind you, or
worse yet, revolve around the room. This would nearly always be unnatural
and distracting. In summary, classical music has some constraints that
must be taken into account when making a multi-channel mix. Furthermore,
with six or more channels, the opportunities for the recording or
re-mastering engineer to make mistakes multiply geometrically.
So, what are the alternatives today for multi-channel music? The
choices are varied, and the technology at times complex and confusing.
First, it's important to understand the terminology. The home theater
world has introduced a useful nomenclature to identify the number of tracks
in a recording, though it is not always applied consistently. Most will
remember seeing the number combination "5.1" on DVDs and some CDs. This
designates that the recording was made with five main channels and a single
sub-bass channel. The first digit is the number of full-range channels,
and the digit following the decimal is the number of sub-bass channels, or
low-effects channels as they are known in the theater world.
Previously, we recalled the attempts at surround sound in the 70s. The 90s
saw a much more successful launch of high fidelity, discrete, multi-channel
sound. Not surprisingly, it too got its start in movie theaters. Dolby
had attained considerable success with their Pro Logic encoding, and it
became ubiquitous in the 1980s.
Not one to be satisfied with a near-100% market share, the folks at Dolby
continued exploration of other technologies. Recognizing the power and
impact a soundtrack in surround could have on audiences, the film industry
had been asking for better multi-channel sound, and had decided that six
channels was the minimum configuration. Digital recording was all the
rage - the CD had been successfully launched and was dominating the market.
It was clear that a digital format was the way to go.
Experimenting in several areas, the engineers at Dolby had introduced the
first Dolby Digital optical technology for film soundtracks by 1992. By
1995, the format had been adopted for use on laser discs (often referred to
as "AC-3," which is actually the type of compression algorithm used in the
coder). A year later, the format had become the standard for DVD.
I won't go into too much more history, as there are better resources on the
web. Try this white paper at the Dolby site for a good overview:
Surround Sound - Past, Present, and Future
http://www.dolby.com/ht/430.l.br.9904.surhist.pdf
Although the 5.1 format is somewhat informal, it does generally standardize
use of channels. Lack of standardization killed quadraphonic sound before
it could get started. The ".1" is for low frequency effects (LFE). In a
movie the low effects might include explosions, low bass from the music
soundtrack, or other sub-sonic material such as the low rumble of a
starship engine. The other five channels are also well-defined in the
theater world: there are three channels across the front - left, center,
and right - with the majority of sound coming from the center channel.
This locates speaking voices and the like on the screen instead of on one
side or the other. The two rear surround channels handle ambient sounds
and movement, such as helicopter flyovers and stadium crowds.
Many combinations of main and LFE channels are possible. A Dolby Digital
(DD) soundtrack might be 2.0, indicating straight stereo in digital format.
Format 3.0 indicates left, center, and right channels. Format 4.0 might be
a digital encoding of a soundtrack that was originally recorded in four
discrete channels where there are left and right front speakers, and left
and right surround speakers.
Recently, 6.1 and 7.1 formats were introduced. Dolby and the folks at
Lucasfilm (THX) are looking into a 10.2 format for the future: that's
three channels across the front, three across the rear, and two on each
side with front and rear subwoofers.
While exceedingly popular, Dolby isn't the only game in town. All of the
DD formats use compression to get as much audio information as possible,
while limiting the number of bits that are required to store or transmit
the data. Although the algorithms are quite different, both DD and MP3 use
compression schemes to keep the amount of data manageable.
The drawback of compression is that it can have an audible negative
effect on the quality of the music. Anyone who has downloaded a highly
compressed MPEG file knows exactly what I'm referring to. DD compression
isn't dramatically noticeable, but in this day of high-capacity optical
discs and fast processors, perhaps that much compression isn't necessary.
Enter Digital Theater Sound, or DTS for short. Originally introduced as a
competitor to DD in theaters, DTS has become a standard in home audio gear
as well. DTS is a 5.1 format too, but there is approximately three times
the audio data as there is in the DD data stream. This means that more of
the original music information is retained, and some feel that this
difference gives DTS sonicly superior results.
As the differences are subtle and subjective, there is an ongoing war
between DD and DTS as to which provides better quality sound, but the
consensus seems to be that either is wonderful, with a slight edge going
to DTS. I concur with this assessment, but you can follow the battles at:
Dolby Evaluates DTS, Part 1 - November 2000
http://www.dolby.com/tech/mp.in.0103.DigitalVsDTS.pdf
As well as the DTS rebuttals at:
DTS Position on "Dolby Evaluates DTS" - 21 November 2000
http://www.dtsonline.com/dtsposition.pdf
DTS Position on "Dolby Reviews DTS...", Part Two - 6 April 2001
http://www.dtsonline.com/dolbyrvu.pdf
The last few years have seen a proliferation of five- (and now six-
or seven-) channel audio gear. DVD players have six-channel outputs.
Receivers with five amplifiers to handle the full-range speakers are common
and inexpensive (subwoofers are typically powered separately). Almost
every receiver or pre-amp produced these days with digital inputs
recognizes and decodes both DD and DTS data streams.
On the software side, DD is the clear front runner with 51% of the 3000 or
so of the available DVD titles including a DD 5.1 soundtrack. DTS today
occupies a mere 3% of the DVD soundtracks. Still, DTS is being included on
more and more DVDs. Nearly all new movies include a DTS mix as well as DD
for the theatrical release. There are DTS theaters out there, and DTS has
some powerful backers. Steven Spielberg is an investor and insists on DTS
for all DVD reissues of his movies. Finally, the superior sound of DTS has
a number of devotees. I expect both formats to survive for some time to
come.
Two additional formats have gotten a lot of press lately: Super Audio
Compact Disc (SACD) and DVD-Audio. SACD is a proprietary technology quite
different from that of the current CD. I'll spare you the details - there
are lots of sources of info on the net. SACD was developed by Sony and
Philips, and manufacturers must be liscenced and pay royalties.
DVD-Audio was developed by the DVD Forum, and therefore is considered
an "open" standard. Both formats offer some level of compatibility
with older formats (CD & DVD respectively). That is, if the individual
producer/manufacturer makes them compatible - there is no hard and fast
requirement in either for backward-compatibility. Also, both technologies
offer higher-fidelity recordings in stereo and multi-channel formats than
CD and DVD.
To date, the availability of classical recordings in either format is
spotty at best, and there's no telling whether both, one, or neither will
survive, but I'll discuss some of the recordings below. Here are links for
more info on SACD and DVD-Audio technologies:
Sound bytes: DVD vs SACD
http://www.zdnet.com.au/biztech/storage/story/0,2000010457,20221895,00.htm
DVD-Audio vs SACD
http://www.techtronics.com/uk/shop/600-dvd-audio-vs-sacd.html
Sony's SACD site
http://www.sel.sony.com/SEL/consumer/sacd/static/
DVD Forum's DVD-Audio page
http://www.dvdforum.org/gen-dvdaudio.htm
Given the lineage of these formats, it is not surprising that Sony's
web page is almost entirely marketing hype, and the DVD Forum's page
is extremely technical.
Equipment
In general, this list is concerned with classical music. Discussions
of audio equipment don't often happen here. This isn't because I don't
believe the equipment can be important, even crucial, to an effective
musical experience, but rather that such discussions often digress into
arcane debates of dubious scientific basis, sometimes leaving the topic of
music far behind. I'll discuss technology details a bit later on, but for
now new models with advanced features and capabilities are being introduced
every month and so any discussion would be very limited and quickly
out-of-date. I recommend the following magazines that feature equipment
reviews and discussions of many of the issues I'm raising here:
Sound & Vision
http://www.soundandvisionmag.com/
The Perfect Vision
http://www.theperfectvision.com/
Stereophile Magazine
http://www.stereophile.com/
Recordings
Right up front I'm going to mention by far the quietest producer of DD-
& DTS-encoded audio DVDs: Naxos. Yes, Naxos, that manufacturer of
ultra-budget recordings by the boatload. So silently have they been
issuing their surround recordings that I almost wonder if they want people
to know about them. Naxos has released a whole series of DVDs, titled
"Naxos Musical Journey," with both DTS and DD versions on each disc.
These discs feature a somewhat inane "travelogue" video track, but the
real draw is the inclusion of DD and DTS versions of some of Naxos' most
popular recordings. So far there are more than twelve releases (the Naxos
site just lists the first 12, but other sites show at least eight others),
containing the likes of Bach's violin concertos, Vivaldi's The Four
Seasons (of course), Bruckner's symphony #4, Mozart symphonies and piano
concertos, Beethoven's piano concerto #1, and other releases with works
by Rimsky-Korsakov, Tchaikovsky, Handel, Verdi, Grieg, and so on. And
just recently they have released their first two DVD-A discs: Vivaldi's
Four Seasons by Juritz and the London Mozart Players, and Grofe's Suites.
I've heard neither, but the reviews for the Vivaldi have been very good,
and the price is right, about $14 compared to the $25 list price of DVD-As
from the majors such as Teldec. These Naxos DVD-As not only include the
24-bit/96kHz advanced resolution surround, but also both DD and DTS!
Not to be outdone, Telarc has entered the multi-channel/high-definition
fray with simultaneous releases of a new recording of Tchaikovsky's 1812
Overture in CD, SACD, and DVD-A formats. Telarc is obviously hedging its
bets as to which format will survive.
Teldec has released a complete Beethoven symphony cycle by Barenboim
and the Berlin Staatskapelle that has been well-received, and discs of
Bach organ music played by Ton Koopman and a collection of a cappella
Renaissance polyphony from Canticleer.
My direct experience with these recordings is limited. I've heard SACD
on about $200,000 worth of equipment, and it was impressive, but I heard
no classical music (it was all jazz and rock). I have yet to even see a
DVD-Audio setup in any of my local stereo stores. I have several DVD-As
and enjoy them for the DD and DTS tracks that are often included with the
higher resolution DVD-A tracks. They are about as expensive as other
DTS-encoded releases, for example, and offer the promise of even better
future sound when and if I get a DVD-A player.
DVD-A or SACD
So, which format - DVD-A or SACD will survive? It's hard say with
assurance that either format will be around in five years. The "early
adopter" market for both was compromised as a result of the paranoia of
the major labels and the RIAA. Whereas nearly all machines that play
normal stereo (CD, MiniDisc, MP3 players), DD, and DTS (DVD players)
formats provide a digital interface to the rest of your stereo gear, both
the stereo and surround outputs from SACDs and DVD-As are provided with
six analog cables. For the high end market, this was a disaster as many
stereophiles like to use expensive and esoteric outboard digital decoders
and other equipment that requires a digital interface. In addition, there
are two major problems with DVD-A/SACD that has yet to be addressed: bass
management and distance compensation. Bass management is a function that
ensures that very low bass is directed only to speakers that can handle it.
Though I have a system that includes five full-range speakers and a
subwoofer, most other installations use two full-range speakers for the
left and right channels and smaller speakers for the center and surround
channels. In such a setup, using bass management cleans up the sound by
directing the bas only to the subwoofer and full-range speakers. The
specifications for home theater equipment specify that bass management be
available for both DD and DTS surround, but no standards at all exist for
DVD-A and SACD bass management, so nearly all players use none. As bass
management can be done in the analog domain, those six analog outputs can
be sent to an outboard device that will perform the bass management, but
this is far too complex for the average consumer. A potentially bigger
problem is distance compensation.
If all speaker and listening arrangements were identical, and the
listener was always sitting in a sweet spot located at the geometric
center, then distance compensation would not be necessary. The
mastering/mixing engineer would know exactly how to mix the surround
channels to provide the best, most focused possible soundstage at the
listening position, because all of the parameters are known. In the real
world, ideal setups are exceeding rare. Most of us must share our space
with other listeners, and large object like TVs and furniture. In the
stereo world, this known as "balance". You can generally adjust a balance
to provide a pretty good image for more than one listener, or for a
listener outside what might be the sweet spot. With five channels, this
gets really complicated. The distance the listener sits from the speaker
must be well known, so that it can be compensated for in the digital
domain. Unfortunately, distance compensation cannot be done in the analog
domain but analog outputs are all that's available for now, so there's no
foreseeable way around this problem. This means that unless your listening
setup conforms exactly to the SACD specification, which is more than a
little at odds with the way most of us have our home theaters set up, you
will not be able to get the sonic image as intended. A good article
concerning the current state of the SACD vs. DVD-A race can be found at
the Sound & Vision web site:
Multichannel Audio Report Card
http://www.soundandvisionmag.com/hot_topics/articledisplay.asp?ArticleID=57
Which do I like? As I haven't spent sufficient time with either format,
I can't really offer an informed opinion. DVD-Audio has a number of
practical and marketing advantages over SACD. First, SACD is an audio-only
format, so no pictures, video clips, etc. are included. When SACD was
first introduced, it was stereo only (with analog outputs, remember), and
so delayed the launch of SACD surround capabilities. DVD-A was a surround
format from the first. Additionally, SACDs will only play in SACD players,
and, if they are dual layered, can also hold a normal CD version that will
play on most regular CD players. This is called a hybrid disc, and is
meant to allow for backwards compatibility. Unfortunately, there's no
standard that says a regular CD version is included with every SACD, so
many are not backward compatible. Here DVD has a distinct advantage.
DVD-As can not be played on normal CD players, but they can be played on
just about every one of the millions of regular DVD players out there. In
recognition of this, most DVD-As include a DD and sometimes a DTS version
of the album as well. This means that nearly all of us with home theaters
can buy DVD-As and listen to the DD or DTS tracks right now, and get the
benefits from higher resolution surround sound. But if you have a DVD-A
player, you can access the "advanced resolution" versions of the music on
the same disc. DVD-As often include both stereo and surround versions at
higher sampling and bit rates than standard CD (which uses 16-bits/44kHz).
The stereo version is two channels at 24-bits/192kHz and the surround
version is six channels at 24-bits/96kHz. But a wide range of variations
are possible, and some of them are not very compelling. For instance,
yesterday I nearly picked up EMI's DVD-A of Simon Rattle and the Berlin
Philharmonic playing Mahler's 10th. Then I read the small print. The disc
includes neither DD nor DTS tracks, and the only "enhanced" definition
tracks were stereo mastered at 24-bits/44kHz, which is only one-quarter of
the sampling rate the format can accommodate. Granted, this is a slight
improvement over regular CD, but at a list price of $30 I passed, and will
probably pass again when and if I do get a DVD-A player.
Listening to Classical Music
So, how has all of this affected my listening? Tremendously. I now have
a multi-channel system that can reveal subtle differences in mastering,
and thus I can tap into the higher-resolution recordings available in
DTS format. The Telarc release of Holst's Planets is a great example.
The performance is very good, as is the sound, but the surround sound
engineering is nearly ideal. The surround channels are used for hall
ambience, leaving the soundstage firmly in from of you, but engulfing you
in the overall sound much as you would find at a concert; a truly magical
experience. Though home electronics can not come close to the sound of an
actual performance - and I've heard systems that should sound live as money
seems to be no object - the difference between a mediocre stereo system and
some well-chosen components carefully assembled can be revelatory.
I'd like to say one more thing about classical music and stereo equipment.
Like many of you, I have for years turned a jaundiced eye towards the
proliferation of subwoofers. They seemed primarily intended for popular
music where a subterranean, but often synthesized, bass is desired. I
had large, full-range speakers with good response down to 30-40Hz and felt
that was more than sufficient for my type of listening. I now have to
admit that I couldn't have been more wrong. The sound of a double bass
completely changes when the harmonics below 50Hz are strong. You feel it
and hear it, and that's the way it is live. Percussion is also affected,
especially timpani and bass drums. And for many recordings, there are
subsonic hall ambience sounds, usually generated but the stage itself, what
provide a foundation for acoustic music that you might not know is missing.
My advice: if you think you already have a fairly solid system, try adding
one or two powered subwoofers and check the difference. You may be amazed
at the improvement of orchestral recordings in particular.
FYI, my audio system:
Onkyo TX-DS777 THX Select Certified A/V Receiver
Toshiba SD-4109X 6-DVD carousel player
Sony CDP-C8ESD 5-CD carousel player
Carver M1.5t power amplifier
Infinity RS-3b speakers, recently rebuilt
Martin Logan Cinema center channel and Script surround speakers
Yamaha YST-SW150 subwoofers (two, one on either side of the room)
Monster Power HTS3500 power conditioner
MIT Terminator 2 cables and interconnects
I should probably also say something about power conditioning, as I think
it is important for any acoustic music recording, especially for classical
music. In order to preserve the signal and move it through the system
without introducing noise and distortion, audio components need stable and
clean power, and they need to be isolated electrically from each other to
avoid the introduction of noise and the degradation of sound that is
usually called "graininess". A good power conditioner can work wonders
with an existing system, especially when listening to solo instruments such
as piano, and is highly recommend.
I've been working on this article for over six months now. I kept hoping
to be able to relay more direct experience with the formats, but that has
been slow in coming. I figured that if I didn't get it out soon, the whole
article might become obsolete. If anyone has any questions or comments in
the context of improving reproduction of classical music, I'd like to hear
from you.
Dave
[log in to unmask]
http://www.classical.net/
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