by G. L. Taylor [Sony-Superscope Inc. ]
Once it was thought that the magnetic tape had a strong chance of replacing the vinyl record in the hearts and collections of music lovers. Today some probably still hold that hope-or fear-but their numbers are few. A glance into almost any current publication devoted to audio arts will reveal the continued prevalence of Record Power.
Yet, magnetic tape does hold an important place in the audio industry, due to its special capabilities which no record on the market today can equal.
The electronics industry is a fast-changing one. Innovation follows innovation; new products appear, old ones fade away.
As products change, they attract new and different markets.
Conversely, as the markets change, the products must change to accommodate them. This importance of market, then, is a primary concern in the study of trends in open reel tape recorders.
A strong demand for the versatility and high performance standards of open reel tape will always exist in the professional audio industry: broadcasting studios, recording studios, production companies, tape duplicators, wherever a high-quality master is necessary. These same characteristics continue to make open reel an invaluable part of computer operation and the sciences.
As an example of the latter, in a major motion picture, a bank of open reel tape decks is used in a program to translate the speech of dolphins. As with all good fiction, this movie has its feet planted firmly in fact: the ability of dolphins to communicate and their high level of intelligence long ago intrigued real-life scientists sufficiently enough for them to initiate similar programs at marine laboratories and universities around the world.
Fig. 1--Block diagram of a servo-control motor.
More importantly, the same qualities that keep open reel an entity in the professional market will serve it well in the consumer market, for a variety of reasons.
1. Increasing sophistication of music lovers. There are those who demand the best simply because it is the best. Others have weighted cassettes and cartridges in the balance and found them wanting. Many have started out with cassettes or cartridge units and are ready to step up. All of these people recognize and salute the well-deserved superior status of open reel.
2. Versatility of open reel. Cassettes and cartridges have as their principal advocates those whose primary interest is listening to music. For them, versatility is likely to be the ability to cut out commercials when recording off the air-if indeed they're interested in recording at all.
However, those whose interests extend to creating their own source material often demand more: three heads for editing and monitoring; special effects capabilities, such as echo, sound-on-sound, sound-with-sound, mic-line mixing. These are functions of open reel units.
3. Transition of music from vicarious listening experience to gut-level participatory experience. It used to be that composing and performing were arts that look incredible talent and many years to develop. Consequently, direct participation was limited to a relative few. No longer. Today music has become a more direct, personal expression of raw emotion open to nearly everyone with the urge to express. It is a trend characterized not so much by talent as by sincerity. This is evidenced by soaring sales of musical instruments in the past decade and by the tremendous outgrowth of new musical groups, each performing its own music. The fact that some have hit fantastic success almost overnight has encouraged countless others to leap on the music bandwagon.
An open reel tape recorder is vital for any group of burgeoning composer-musicians hoping to succeed. For creative editing and special effects are as much a part of this music as electric guitars, earnest vocalists and arcane lyrics.
4. Money to spend. All of the foregoing market trends would be worthless in an indigent society. People can pay more for open reel equipment simply because they have more to spend. Despite unemployment and inflation, disposable income seems to be on the rise.
These changing market trends have naturally had their effect upon products. But the situation is not without a certain irony, for open reel, in its increasing sophistication, seems to run counter to the prevailing trend toward simplicity in tape recorders today.
For dozens of years, a prime objective of the tape recorder industry was miniaturization, heralded in by the transistor and the integrated circuit. This trend was reflected in May 1967, in a series of prognostications published by AUDIO MAGAZINE on the occasion of its 20th anniversary. Tape recorders, said industry leaders, would get smaller and start using slower speeds, with better results than the higher speeds of older models.
Coincidentally (7) the same issue of AUDIO carried an article on the Phillips cassette and two rival forms of the tape cartridge: Fidelipac, a standard of the broadcast industry, and Lear-Jet, created by that manufacturer of personal jet aircraft in conjunction with Ford Motor Company. In 1967, none of these configurations were viable competitors for either the record or open reel tape. Their FI was admittedly far from HI: the article considered them adequate for automotive use, but not "sonically attractive enough to warrant the attention of the serious audio buff." Today, of course, that's all changed. Serious audio buffs by the hundreds are buying cassette and cartridge units-and not just for their cars. Technological advances have apparently fulfilled the prophesies of the industry's augurs. Innovations such as Dolby and chromium dioxide tape coatings have put cassette performance, even at 1 7/8 ips, on a par with records. Four-channel sound and a wide selection of software have made cartridge units a force to contend with in the home entertainment field. Ultimate miniaturization is nigh. Already palm-sized cassette units exist that give better performance than behemoth open reel models of yesteryear.
At least one of these, SONY's TC-55, features a select switch that enables the unit to capture music with adequate, though not high, fidelity. Further refinements will undoubtedly follow.
Fig. 2--Ferrite head vs Permalloy head, demonstrating the effect of laminations
upon gap width and core smoothness.
So the cassette and cartridge are now respectable. Anyone with doubts can check prices, for one thing in this ever-changing industry remains constant: good performance still costs more than mediocre performance. The result is that cartridge and cassette tape units have taken over the market previously held by low- and medium-priced open reel units.
Consequently, as cassette and cartridge units become more compact and convenient, open reel units have been forced to become more complex and versatile. Features designed to provide professional-quality performance are finding their way more and more into consumer models.
1. Higher speeds. Paradoxically, as one faction of the industry moves toward the slower speeds predicted in 1967, another faction seems intent on defying destiny. Units with 15 ips speed settings are on the increase-corresponding to demand for the wide frequency response that's a function of these higher speeds.
2. Large reel capacity. To circumnavigate the reduced playing time that results from using higher speeds, an increasing number of recorders are being designed to accommodate 10 1/2 inch reels. In addition, large reel capacity at the lower speeds can be useful to provide greatly extended continuous play.
3. More sophisticated drive systems. Uneven tape motion has long been a bugbear of the tape recorder. Now the sophisticated audiophile can reduce it and its attendant ills--wow-and-flutter and poor tape-to-head contact--with any of a growing number of 3-motor tape decks on the consumer market.
Innovative motor design is also helping to solve the problem of uneven tape motion. Typical is the servo-control motor, which prevents capstan speed variations due to normal voltage or load changes. (Figure 1.) Connected directly to the capstan motor (A) is a frequency generator (B), whose frequency is dependent upon the motor RPMs. The frequency generated is relayed to a servo control board (C) which compensates for variations in the speed of the capstan motor by either increasing or decreasing voltage (D). The result is highly accurate motor speed and consequently, consistent tape motion.
Further sophistication can be found in yet another feature previously restricted by cost to the professional, but now making its way to the consumer: closed loop dual capstan tape drive.
In this system, two capstans isolate the tape from external vibration and abnormal reel movement by forming a "closed loop" of tape around the head assembly. Two current 3-motor tape decks featuring the system, SONY models TC-854-4S and 850, can attest to its efficacy with extremely low wow and-flutter specifications of 0.03%. (Figure 2.)
5. Ferrite heads. Much has been written concerning the hardness of the ferrite head and its resultant ability to resist abrasion. There are other advantages. For example, the higher internal resistance of the ferrite material used in their manufacture allows ferrite heads to be molded of one solid piece of material. By contrast, the Permalloy head must be built up of laminations in order to cut down eddy current losses.
Fig. 3--Sony Model 850, a professional quality 3-motor deck.
The single surface of the ferrite head material can be lapped to a sharper, more precise edge than can the laminations of the Permalloy, permitting more even pole pieces, and ultimately a narrower head gap. (Figure 3.) The effect on frequency response is obvious.
Natural stereo and 4-channel separation is virtually dependent upon even pole pieces and straight head-gaps to prevent sound drop-outs from phase shifting. It's not surprising, then, to see the ferrite head making an appearance on the more sophisticated open reel units.
What else does the future hold? Knowing that the tendency is toward professionalism, we can make educated guesses--or think wishful thoughts. Chromium dioxide tape for reel to reel? Why not, at least at the slower speeds. Refinements in ferrite heads will certainly aid the cause. So will special lubricants to reduce friction, and its resultant abrasion.
Abrasion is one of tape's most insistent drawbacks. Hopefully, the time will come when it's eliminated altogether, or at least reduced to a nominal level. A more efficient method of reading the magnetic pattern on tape would help-especially one that does not depend on tape-to-head contact. As incentive, consider the recently developed phono cartridge that uses a photo cell instead of a needle.
This is a transitory period for open reel. It has lost sales to cassette and cartridge simply because its new identity and market are not yet firmly established. That time is coming.
To be sure, the market for the sophistication provided by open reel is smaller than that for the convenience of its plastic-enclosed cousins. But price differential minimizes that problem-and furthermore, each purchaser of a cassette or cartridge unit is a potential step-up to open reel.
One thing is certain: no matter how far cassettes and cartridges progress, open reel is still the ideal they're measured against. As long as that's true, open reel will remain an important factor in the consumer audio industry.
(Audio magazine, Apr. 1973)
Also see:
Logic Control of Tape Recorders (Apr. 1973)
Tandberg Model TD 20A Open-Reel Tape Deck (Mar. 1979)
Tandberg open-reel tape decks (Apr. 1973)
Cassette Deck Transport Problems (Sept. 1974)
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