Several months ago I reported on the status of the eight-track tape cartridge
format. I related that 1971 had been a sort of "soft" year for
hardware sales in this medium, although the sales of recorded cartridges
continued their upward trend. Then at the CES this year, we were inundated
by a flood of new models of cartridge machines for home and automotive use.
The burgeoning of interest in the cartridge format stems from a general upgrading
of the quality of both hardware and software in this medium, and most especially,
in the adaptability of the cartridge to four channel sound. There are even
those who envision the cartridge as a true high fidelity medium, their reasoning
being that since cassettes and cartridges both use magnetic tape, it is just
as technically feasible to improve the sonic qualities of cartridges as was
the case with cassettes. In fact, it is pointed out that the tape cartridge
operates at 3.75 ips ... twice the speed of a cassette, which should be some
advantage in the initial stages of any improvement program. Before we summarily
dismiss such a notion of a high fidelity tape cartridge, it must be conceded
that just because cartridge tape is back-lubricated, this does not preclude
the use of specially formulated oxides which can afford extended high frequency
response. One must also admit that improved magnetic heads for the cartridge
format are a relatively straight-forward matter with today's advanced head
technology. As to the admittedly poor signal-to-noise ratio of cartridges,
they can be Dolbyized, just the same as cassettes. As a point of interest,
the always busy New York hi-fi rumor mill has been buzzing with news that
either Columbia or Ampex Stereo Tapes, or both, will produce Dolbyized eight-track
cartridges. Obviously, if this comes to pass, at present one would have to
use a typical Advent/Teac/Concord outboard Dolby box to playback the cartridges.
It goes without saying that tape cartridge players with built-in Dolby IC
chips would soon appear on the market.
Okay . . . so we can make a true high fidelity cartridge. And now comes a chorus of protesting voices ... "who needs it?" Why do we want tape cartridges which are admittedly bigger and clumsier than the handy cassettes? Most cartridges are played in cars, which even in the models with the quietest interiors, have much higher ambient noise levels than exist in homes and apartments. So why bother with fancy cartridges in which the extended high frequency response would be swamped by the noise of the mobile environment? And why have hi-fi cartridges when the sound systems in most cars, especially the loudspeakers, are of such poor quality? All of these are valid questions, but there are some answers.
Central to the whole idea of tape cartridges and the reason for their continuing high volume of sales, is that they are an excellent medium for listening to music in an automobile, from a purely mechanical and handling viewpoint, and of course, afford selectivity and choice of music. Their endless loop principle and ease of insertion in the playback unit makes tape cartridges relatively safe to use in a car with minimum diversion from the business of driving. Even when discounted, tape cartridges are generally more expensive than the equivalent Lp records. It was only logical that many people did not want, or could not afford, to duplicate the music they listened to on cartridges in their car, with disc recordings for playback in their home. Thus, in increasing numbers these people are acquiring eight track tape cartridge playback decks, and incorporating them in whatever kind of music system they have in their homes, and their tape cartridges are performing "double duty." Needless to say, with the much quieter ambience of their home listening room, compared to their car interiors, many are a bit shocked by such things as tape hiss, crosstalk, print-through and other ills of the cartridge not audibly apparent in the car. These people who make dual-use of their tape cartridges are obviously those to whom a really high quality cartridge would have an immediate appeal.
However, strong though these reasons be for the introduction of a high fidelity tape cartridge, the most compelling reason of all is the potential of this medium for quadraphonic sound. It was a comparatively simple thing to re-assign tracks in the tape cartridge, so that instead of four two-channel programs of music, we had two four channel programs. This change, of course, reduced the playing time of the cartridge, which necessitated the use of a thinner tape to accommodate some of the longer classical works. As it stands now, a quadraphonic cartridge is of approximately 50 minutes maximum duration. Now it must be realized that a quadraphonic cartridge is true discrete four-channel sound. Apart from the program break occasioned by the endless loop tape cartridge format, (and of course without the high fidelity) the quadraphonic cartridge is the equivalent in "discreteness" of a four-channel open reel tape.
Quadraphonic cartridges and associated playback equipment are one of the least expensive ways to "get into" discrete four-channel sound. And by all odds, quadraphonic cartridges offer a larger selection of discrete four channel sound than either open-reel tape or CD-4 disc.
The rub in all this of course, is that the quadraphonic cartridges suffer from the same sonic ills of their stereophonic brethren. Frequency response isn't too bad ... out to about 7-8 kHz, but we could certainly use more . . . if we could get it without the penalty of more tape hiss. The tape hiss is really the crux of the matter.
On stereo tape cartridges it is bad enough hearing the hiss in front of you. On quadraphonic cartridges you get the hiss both front and rear, which is not only disconcerting, but in the case of classical music recorded with hall ambience in the rear channels, the ambient reflections are swamped by the tape hiss! The situation cries for the application of Dolby noise reduction, and hopefully the Dolby IC chip will save the bacon, from the standpoints of minimum spade requirements for the inclusion of the circuit in cartridge playback units, and moderate cost.
While we are on the subject of tape cartridges it is worth noting that the recording of cartridges in the home is rapidly gaining momentum. Capitol's Audio Devices division, whose "Audiopaks" blank cartridges has dominated the field, tells me that sales of blanks have been increasing significantly over the past year. Scotch has a new low-noise oxide blank cartridge which is enjoying brisk sales. There are a number of tape cartridge recorder/playback units on the market. One of the latest and perhaps indicative of a new generation of this type of unit is the 3M/Wollensak Model 8055. This stereo recorder/player has a special timing counter which displays elapsed time in minutes and seconds, along with a special cueing system that insures that you are at the beginning of the tape when the unit is placed in the record mode. To further uncomplicate the 'always tricky business of recording on endless loop tape cartridges, the Model 8055 has an automatic eject system which prevents accidental erasure of previously recorded material. The unit can also move the tape in a fast-forward mode at 2 times normal speed. This of course would ultimately be significant if one wanted to Dolbyize the tapes using an outboard Dolby box, since after recording the Dolby signal for record calibration, you could advance to the 4th sequence and then run fast forward until you could read the playback of the signal at the beginning of the first sequence. Signal-to-noise ratio of this unit is claimed to be better than 50dB, with a frequency response of 40 to 15 kHz. Giving 3M the benefit of the doubt that these are probably fairly accurate figures, this unit certainly qualifies as high fidelity in anyone's book. I hope to bring you a personal report on this intriguing unit before long. You will recall that in my last report on tape cartridge sound several months ago, I had taken my new car to Mr. Harold Wally, of Wally's Tape City in New York, for a new speaker installation to replace the miserable squawk boxes that were original equipment on the car. I related to you the total involvement of Mr. Wally in the auto stereo business. He has been in the field since it's inception, and his place is famous for custom installations, even in tricky sports car situations. Mr. Wally rightfully points out that the speakers used in most new car cartridge systems are not only cheap and of poor quality, but were not specifically designed for use in car stereo systems. Furthermore, he states that the placement of the speakers is strictly a haphazard affair, with little or no regard for proper baffling. Placed in kick panels, or underneath dashboards, bass response is poor or almost nonexistent. Mr. Wally is now on his fourth generation of speakers, designed to work efficiently in his favorite baffle, the doors of the car. The speakers are six inch units with stiff, but light cones with a flexible surround and a dome in the throat for high frequency dispersion. The baskets are understandably shallow so that they can fit into a wide variety of doors. Magnet structure is on the order of a half pound or more, rather than the puny 3/4 to 1 oz. slug found on the usual car speaker. Even though car doors vary widely in their internal construction, depending on whether the windows are electric or manual, Wally usually can find a reasonable place to mount the speakers. Wally stated that getting a decent bass response is the name of the game in car stereo installations. With his special speakers fitted snugly into the door with flanges sealed, the volume of entrapped air in the door is sufficient to give some good baffling and the bass response is quite respectable.
With the superior efficiency of Wally's speakers I can now drive the system to louder levels than one could tolerate, with minimal distortion at that highest level. The rear speakers mounted on a shelf above the car trunk, were changed and replaced with Wally's special 6x9 units with a hefty 15 oz. magnet. With the entire trunk area acting as baffle, the bass response was quite good. The overall system sound employing the speakers in the door and the units in the rear, is fairly smooth and wide range, and is so much cleaner and more enjoyable than the original there is simply no comparison. Tooling down the road, and listening to a nice classical recording or some good mood music of my choice, sure beats the random afflictions of the radio. Wally's installations are neat and as they say in racing circles . . . "quite sanitary". He has several models of speakers, with the best going for about 35-50 dollars installed depending on the complexity of the job.
To end this epistle on tape cartridges, and to show you the extent to which some people go to improve their car listening, one reader writes that he installed four 5 inch tweeters and two Electro-Voice 15 inch woofers in his car trunk, plus KLH Model 17 speakers in back of the rear seats! This array is driven by an inverter-powered Dyna 120, with PAT 4 pre-amp! The mind boggles!
One final note ... Mr. Wally says that trying to convert normal car stereo players to four-channel is much too difficult, and that a four-channel player of the type made by Motorola, Panasonic or Pioneer should be used as an add-on, which can be removed when you trade your car. That is next for me, with Wally telling me a simple change or wiring to the front and rear speakers and I'll be immersed in quadraphonic sound!
(Audio magazine, Feb. 1973; Bert Whyte)
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