Continuing my series on the historical technology
of sound recording. Today we look at record changers, the rise of vinyl, and the first "Format Wars"...
The mid-thirties saw the introduction of improved
players. Although gramophones and Victrolas, which had
been built to last, remained in use, now players were
introduced that could play several discs in a row,
automatically, without user intervention. They were
called "record changers" and suspended a stack of records--typically as many as six--above the turntable
on a tall spindle. When the user started playing a
stack, the spindle would allow a single disk to drop to
the turntable, where it would fall gently on a cushion
of air created by the falling disk itself. A mechanism
would then place the tone arm at the beginning of the
record. When the record ended, the tone arm was guided
by the record's groove into a center area that signaled
the tone arm to rise and return itself to its resting
place while the next disk dropped on its own cushion of
air atop the disk below, and the process was repeated.
The spindle was designed to sense when no records
remained, at which point the record changer would turn
itself off.
And all of this was done mechanically, with no
computer circuits around to help.
Record changers were so popular that albums of
records were designed to be played on them, with a
properly arranged stack having sides 1, 2, and 3 on
sequential records, which, when turned over, continued
with sides 4, 5 and 6, in that order.
The motor
of a record changer was electric, not clockwork, as the
old Victrolas had been. That was a necessity, as no
clockwork motor could store enough energy to play an
entire stack of records. And since electricity was
therefore a
requirement, there was also the opportunity to improve
sound quality with another invention: The electronic
amplifier.
At issue was the fact devices that picked up sound and converted it to electricity, did so in minute amounts. On the other hand, magnet-based devices to play sounds
back--loudspeakers--required huge amounts of current to
do so. A device was needed that would amplify the
electrical current, without otherwise altering the
waveforms of the signal as it rapidly changed from
positive to negative.
The
vacuum tube that made this possible was, surprisingly
enough, an offshoot of the light bulb and Thomas Edison
held the patent for a primitive version of it, though he
had no idea of what use it might be. Like the light
bulb, the vacuum tube consisted of an evacuated glass
bulb containing a filament. However, in this case, the
heated filament was connected only to a negative
electrical source. Across the vacuum was a cool plate
connected to a positive wire. (Remember, electrons are
negative.) The heated filament radiated electrons, which
were scooped up by the plate. This allowed a completed
circuit, as long as the filament remained negative and
the plate, positive. Current could never go in the
opposite direction. (Such a device is called a diode
and, while they are useful in certain circumstances,
none of them apply to this essay.)
Being a simpler time with fewer distractions, any
number of hobbyists played with the concept of the
vacuum tube. The next basic advance was called the
triode, though it didn't make use of a true vacuum.
Later versions did.
Essentially,
a triode uses three connections to work its
magic. In between the filament and the plate, a
component called the grid is inserted. The grid
can be made either negative or positive; as the polarity changes,
so does the amount of electrons that can reach the
plate. The best part is, the grid voltage/current can be
very small, yet have a giant impact on the amount of
current flowing through the tube.
Voila! A triode is an amplifier. The vibrating needle or stylus
in the record groove, sets up a small, varying electric
voltage by vibrating a magnet within a coil of wires.
That voltage, passed through a triode, controls a
large current, powerful enough to work an electromagnet,
making it vibrate in sympathy with the stylus. That
electromagnet, in turn, alternately--and thousands of
times a second--attracts and repels a cone of cardboard
in which an iron wire has been embedded. That cone,
pushing against the air in the room, reproduces the
original sound.
In 1948, Columbia Records introduced a significant
modification to the phonograph record. The idea was to
cram a whole album of records onto a single, two-sided
disk. To accomplish this, they slowed the
speed from 78 revolutions per minute to 33 1/3,
narrowed the size of the groove which allowed the
grooves to be placed closer together, and used the largest
practical size, 12 inches, for a record (most 78s were
10 inches across). And they switched from shellac to
vinyl, which provided a surface so quiet that the
increased noise inherent in narrow grooves and slow
surface speed was not apparent. The end result: It was
now possible to store an entire collection of songs,
such as had been released as an album of records, on a
single "record album."
The next year, however, RCA introduced a competing
format. Also making use of a slower speed (45 RPMs) and
vinyl for improved noise levels, these were the
minimum record size for 78s (7 inches) and also had
a much larger spindle hole to better accommodate the
mechanisms of juke boxes. In terms of play length, 45s
were equivalent to 78s.
Columbia had built players for
their 33s, as they came to be called, that of course
could not accommodate 45s, though they were able to play
the home user's backlog of 78s. RCA designed players for
their 45s that could play nothing else. And the game of
Competing Formats was on.
Until 1950,
consumers held their breaths and eagerly read each issue
of Popular Mechanics for predictions of which
format would succeed. Remember, consumers who guessed
wrong would find themselves the owners of unplayable
records and useless players.
However, since the
difference in formats was not patentable, third-party
phonograph manufacturers were happy to produce players
that could adapt to any of the existing formats.
The spindle size was the same for 78s and 33s, and a
large adapter could easily allow a standard player to
accommodate 45s. The change in speed was managed by a
speed control that simply changed gears on the
turntable. And a flipable needle allowed the playing of
the wide-grooved 78s or the narrow-grooved 45s and 33s.
And it turned out there was a place for both formats.
45s, holding just two songs apiece--typically an "A" side
and a less-popular "B" side--were inexpensive, marketed
to teenagers, and were thought of as "singles." They
were very popular at parties and radio stations. 33s, on
the other hand, were marketed to adults, especially fans
of classical music pieces which, because it had been
written before the invention of the phonograph, tended
to run far longer than the 3 1/2 minute length of a 45
(or 78).
Rarely used variations occasionally appeared. For
example, 7" 45 RPM "EPs" (extended play) records could
hold two songs per side by lowering the volume and
therefore the groove width. Conversely, 12" 45 RPM disco
releases (with or without the wide center hole) allowed
a wider groove to accommodate loud, repetitive bass
lines. And 7" 33 1/3 RPM "mini-albums" had room for
three or four songs per side. Mostly, however, these
size variants were used to attract consumer attention
and succeeded simply because they were so rare.
It was also possible to embed a picture in a record, by
covering it with clear vinyl instead of the blackened
kind. The sound quality was slightly lessened (clear
vinyl isn't as quiet) but "picture albums" were, and
are, collector's items sometimes fetching thousands of
times the record's original list price.
The
low-tech requirements of the phonograph record enabled
many curious variants. For example, Red Raven Records
included a whole circle of small, embedded drawings.
When the "Magic Mirror" device was placed on the record
as it played, the angled mirrors turned the drawings
into a simple animation.
The
device was derived from the popular 19th century
Zoetrope
animation wheel. Although it couldn't be used on a
record changer, children's record players only played
one disk at a time anyway; so that wasn't a problem.
Last April, a collection of 20 Red Raven records with an
original Magic Mirror sold on eBay for $515.
But the most successful variation was introduced in 1958
(though patented in 1931): Stereophonic sound, soon
shortened to "stereo". For at least two decades, this
innovation was found only on 33 1/3 RPM records, though
there was no real reason for the limitation. To create a
stereo recording, the original performance had to be
recorded using at least two microphones (simulating a
listener's two ears), and the signal from each
microphone had to be kept distinct from the other. This
was normally done by recording onto recording tape with
two tracks, where all the circuitry was duplicated: Two
amplifiers, two recording heads, and so on. The two
channels of sound were then physically associated by the
tape so they couldn't get out of sync.
As mentioned previously, the sound in a phonograph
record groove was stored by causing the groove to vary
from side-to-side. When a needle was placed on a
spinning record, it was forced to follow the groove
which duplicated the original sound. (Even without an
amplifier or loudspeaker, if you place your ear very
close to such a needle, you can hear the music, albeit
very faintly.)
In a stereo record groove, the groove is V-shaped, and
each side of the groove carries the information
for one channel of the program. When played by an older,
monaural (single-channel) player, the needle would
average out the information, combining it so the
listener could hear both channels from one speaker. When
played on a stereo player, the needle would vibrate in
two planes, each 45 degrees from the other. This complex
movement allowed the two channels to remain distinct, to
be sent to two amplifiers which drove two loudspeakers.
The very cool side effect of this was that it was a
backward-compatible system. When a mono record was
played on a stereo player, the needle's movement was
identical for both left and right channels. There was
therefore no true stereo signal; yet the sound still
sounded better coming through two speakers than one.
Anyone will agree that the experience of listening to
stereophonic sound is much more satisfying than
listening to mono. Yet there's no denying that the
forward and backward compatibility of stereo records
with mono players, and mono records with stereo players,
was the primary factor in the new technology's quick and
easy acceptance.
Contrast that to the next enhancement, introduced in
1971: Quadraphonic sound. If two speakers made music
sound better than one, wouldn't four speakers make it
sound even better? However, there were three
competing formats and, while two were compatible with
stereo players, they were not really compatible with
each other.
To produce a quadraphonic record, at least four
microphones were required and the performance had to be
recorded onto at least four channels on tape. At that
point, each of the competing systems diverged.
Two of the systems used a mathematical combination of
the four channels to produce just two. One of the
channels was "subtracted" from another, while the other
was "added." Circuitry in the player recreated the
original four signals, more or less; they were then
amplified separately (by four amplifiers) and
each sent to one of four loudspeakers. These two systems
differed only in their mathematics and could be
successfully played on stereo players without losing any
of the sound.
The two companies--Columbia's system was called SQ and
Sansui's system was designated QS--claimed that the
records of one would not play properly on players
designed for the other. In reality, though, the only
difference was from which speaker a specific instrument
would be reproduced. (By the way, albums of either type
will be decoded spectacularly through a modern Dolby
Surround Sound system.)
The third system came from RCA, the company with a
spectacular parade of failures in the Competing Formats
wars. Not only did their CD-4 quadraphonic system tank,
so did their Video Discs and, for that matter, their 45
RPM EPs. Their fault seems to have been
over-engineering. In CD-4 (which has no relationship to
today's compact discs), the two rear channels were
encoded at an ultrasonic frequency and combined with the
front channels. The result was a stereo record with two
"carrier" channels. If played on a regular stereo, the
rear channels simply weren't reproduced. In fact, they
were generally erased from the disk by the
relatively-clunky stereo needle. They had to be played
on a player with a special--and expensive--CD-4 needle
and cartridge. The cartridge itself decoded the extra
signals, sending four channels of sound to the
four-channel amplifier. And even then, the ultrasonic
channels generally wore out after a few plays.
And so quadraphonic sound failed, only to reappear a
quarter of a century later as Surround Sound.
Quadraphonic failed, I maintain, because of the
competing systems--something that wouldn't have happened
if the companies involved were more concerned with
improving the lives of people everywhere, than in
improving their own company's profits. Dolby Surround
Sound succeeded, on the other hand, because there was no
other format competing for the public's attention (the
various formats are all compatible), and also because
the system is thoroughly forward-and-backward compatible
with non-Surround Sound disks.
Probably the most famous record of all was made in 1977,
with two copies pressed on gold disks. This was the
Voyager record, and each of the gold disks was
attached to one of the Voyager spacecraft launched that
year and sent into deep space. The recording includes
greetings in 55 languages, including Akkadian (a
language spoken in Sumer 6000 years ago!) and music
ranging from the second movement of Bach's 2nd
Brandenburg Concerto, to Chuck Berry's "Johnny B.
Goode."
At the speed at which the probes are traveling, it will
take them about 40,000 years before they reach the
nearest star. It's interesting to ponder the fact that
if one of the probes should return to Earth now, a mere
thirty years after their departure...we'd be hard put to
find a phonograph to play the record on.