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| Commentary |
| All Things Must
Pass |
The Little Spinning
Silver Disc is not quite done yet! |
by Rod Nattrass
In the past hundred years or so we have seen a number of different
music reproduction media come and go. Wax cylinders, shellac
and then vinyl records, magnetic recording tape…and
now the Compact Disc is about to follow these venerable standards
into the history books. Word in the industry is that the 44.1
KHz, 16 bit music format may soon be a thing of the past.
The first CD’s came to market in late 1982. By the late
eighties, as the price of the players started to drop, CD sales
began to exceed the sales of vinyl records. The general public
enthusiastically embraced the convenience of a disc that could
hold up to 74 (later 80) minutes of 20 to 20,000 Hertz audio
with a 96 decibel dynamic range, and a noise floor below the
threshold of hearing.
I recall that when CD’s first came out, audiophiles
were somewhat skeptical of the claims that digital sound was
better than analog. In some ways they were right. A lot of
the first releases were simply direct transfers of the original
analog master tapes, which would have been mastered for the
format for which they were intended, the LP record. This would
mean that they had a slightly exaggerated top end, something
that was done to overcome the limitations of the playback medium
itself. These recordings were also limited at the bottom frequencies.
You could not print too much bass information on an LP or the
cartridge would literally jump out of the groove and cause
skipping during playback.
The unfortunate result was that the first CD’s that
were re-issues of older material were often somewhat thin and
sometimes harsh and brittle sounding. As the medium matured,
the record labels realized that they needed to re-master older
tapes specifically for the CD, and the sound quality was markedly
improved.
Another very important development was the ability for artists
to record their music digitally. By the 90’s more and
more studios had become fully digital. The all digital recordings
took full advantage of the medium and really allowed engineers
to exploit the dynamic range and low noise floor, showing off
the technology to its fullest extent.
Slowly but surely, digital technology continued to improve.
Better and better analog to digital and digital to analog converters
were designed that drastically improved sound capture and reproduction.
The biggest improvements came with the implementation of oversampling.
Oversampling helped to deal with something called “aliasing” which
could happen to the signal during conversion from a continuous
analog wave to zeros and ones. When signals approach the Nyquist
frequency, which in the case of the Red Book specification
is one half of the sampling frequency of 44,100 Hertz, or 22,050
Hertz, they can fold back on themselves and produce nasty sounding
digital artifacts. To prevent aliasing from occurring a “brick-wall
filter”, which has a very steep cut off slope, was used
to make sure that no frequencies past 20,000 Hertz went through
to the converters. This kind of filter is both difficult and
expensive to manufacture. A sharp filter like this has its
own problems as well; it tends to ring at the cutoff frequency.
Oversampling the signal allowed the removal of this filter
by moving the aliasing up into the inaudible range. I watched
and listened as we went from 2 to 4 to 128 times oversampling.
Finally, the converters got to the point where even die-hard
analog audiophiles were happy to accept the digital medium
into their enclaves.
As a result the Compact Disc became the number one audio format,
but this is changing…
More and more people are listening to their music on an MP3
player. They are downloading their music off the internet to
be played back off of either a hard drive or directly from
RAM. The files are often 128 kB (or lower) MP3’s. These
people seem to delight in packing as many songs as possible
into these little gadgets. Many of them do not seem to care
about the quality of the sound at all. They will encode the
music files at very low bit rates so that they can have hundreds
(if not thousands) of songs available on demand. More often
than not, they are listening to the music on cheap headphones
or ear buds.
This is a sad state of affairs. It goes against everything
audiophiles believe in. I don’t think any of us would
be happy with the mangled sound quality of a 128kB MP3 sound
file. Where does that leave us?
Apple’s iTunes store has chosen to use the AAC (Advanced
Audio Coding) process to encode their files. This format is
superior to MP3 in many ways, and definitely sounds better
on lower bit rate files. Some of the other brands of MP3 players
will accept this format, check before you buy.
Hopefully, some clever entrepreneur will realize the need
for higher quality sound files and start up a site with an
option to download songs at higher bit rates. I find 256 kB
files to be acceptable, and 320 kB to be almost as good as
the original. With today’s high speed internet connections
there is no reason why this cannot be done. Sure, a 256 kB
file is twice the size of a 128 kB file, but we could probably
all live with only 400 songs instead of 800 to choose from.
The other important issue that must be addressed is the headphones.
Many of these devices do not come with very high quality headphones.
Spend some money on better ones after you do some intensive
listening tests. Oddly enough just being expensive doesn’t
seem to guarantee anything. Let your ears be the judge.
At the other end of the quality spectrum, audiophiles now
have an ever increasing selection of titles to choose from
in both SACD and DVD-A formats. The little spinning silver
disc is not quite done yet! These formats offer multi-channel,
very high quality audio that will satiate your desire for superior
sound.
I’m still on the fence a bit about multi-channel audio.
I prefer it to be used in the more classical sense of allowing
an engineer to capture the ambience of the space in which the
recording was made, as opposed to having instruments flying
around all over the place. But the art of multi-channel mixing
is still very much in its infancy, and I’m sure that
everything that can be done will be done. The good news is
that most titles also have a stereo version of the recording,
just in case you don’t have a listening room with a 5.1
speaker set up.
Of course, the CD is not just going to disappear all of a
sudden, anymore than the LP did. Independent artists will still
sell CD’s at their gigs. Independent and College Radio
stations still want a band to send in a CD. They are going
to be with us for a while.
The major record labels should be happy to sell their stable’s
music on the internet. Since they would have no package manufacturing
costs and no physical distribution costs, it makes fiscal sense
that they would embrace this concept. It would also allow the
return of the single, as there is no need to release a whole
album’s worth of material all at the same time. Artists
could finish a mix of a song and upload it right away for immediate
public consumption.
This technology also opens the door to re-mixes of songs.
There is a new trend for artists to actually post the multi
track files of their songs. This allows aspiring producers
to re-mix the song and post it at a designated website, where
the mixes are usually voted on by the other participants.
I recently recorded a song with three other artists, a drummer
from Pender Island, B.C., a guitarist from Victoria, B.C.,
and a multi-talented fellow who provided bass, guitar and harmony
vocals from Ohio. I would upload a rough mix of the song and
post it to an FTP site. The other artists would download the
song, come up with additional parts, and then send me back
their part(s) as wave files, which I would download and add
to the work in progress. It was truly amazing.
Ages ago, I remember seeing a rather obscure movie from 1976
called “The Man Who Fell to Earth” that starred
David Bowie. It was a science fiction movie that was set in
the future. The movie itself was unremarkable, but there was
a scene in it where the main character places a tiny little
cube into a device that instantly begins to play music. That
scene has stuck in my head all these years. I have been waiting
patiently all my life for technology to catch up to that scene
in that movie.
We are there! |
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