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Is Disc Recording Obsolete

Wireless World, December, 1943.
    
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This is question 16 from the Wireless World Brains Trust series.
When the war ends we shall have an un-rivaled opportunity of remedying the mistakes of the past and making a new start in more than one branch of wireless. That has already been pointed out in Wireless World, but no one has mentioned the gramophone as a proper subject for a radical change. Is it agreed that the technique of the gramophone is due for supersession, and, if so, what system of sound recording for domestic reproduction should be adopted in its place? JOHN HOPE.
STUART BLACK criticises disc recording, especially in its present form, and suggests directions in which improvements should be made.

As one keenly interested in high-quality reproduction who has followed the progress of sound recording since the days of the early Edison phonograph, I am, perhaps, as well qualified to open this discussion as are others of greater technical attainments who may well be side-tracked from the ultimate object in view by irrelevant considerations.

Quite frankly, everything about our present methods of reproducing recorded music in the home appals me. There has been progress, of course, but it has been in spite of the basic methods employed, and not because of them. Fundamentally and mechanically, I maintain that the present methods are worse than those of the original Edison phonograph.

As a matter of interest let us compare the present-day gramophone with the Edison. We will ignore the electrical pick-up, which would obviously have been applied to the Edison if it had survived, and electric drive, which was, in fact, fitted to the more expensive Edisons. The Edison phonograph had a completely smooth record without any abrasive material, and in the later Blue Amberols an almost indestructible material composition was used; the stylus was a smooth sapphire or diamond; the traverse was mechanically driven so that the record had only to draw along the minute weight of the stylus-holding gear, and not the entire pick-up head and arm; the records were hill-and-dale cut so that the amplitude was, or could be, far greater if necessary; and, best of all, the lineal speed of the track under the stylus was constant. In the case of the present disc gramophone not one of the above advantages exists, for the record is deliberately made abrasive; the stylus is for all practical purposes always a steel needle, both of which factors make for scratch and all kinds of surface noise; the record groove has to drag the whole contraption along, and the contraption has to be massive enough to provide the necessary inertia for the relative movement of the pick-up system proper; the amplitude is strictly limited by the distance apart of the grooves, and the necessary thickness of their walls, which are often, alas! even then all too weak. Finally, the speed of the record relative to the stylus is constantly varying. How can one expect even tolerable reproduction under such conditions? Yet the miracle is that it has been attained, to a large extent by sheer misplaced ingenuity.

Now, for a moment, let us consider why, if it is agreed that there were such overwhelming advantages in the Edison, or cylinder, machines generally, they have completely died out. There can be but one main answer, and that is storage. The space taken up by even a dozen of the old phonograph records would accommodate possibly a hundred 12 in. discs. Two subsidiary reasons for the eclipse were, I think, ease of manufacture, by pressing instead of moulding (though possibly modern methods of hydraulic pressing plus plastics might have overcome this), and length of playing, which was obviously more limited than on the disc.

What is the position now? Over and over again I have heard people say that the present position is due to vested interests and the amount of money locked up in the present system; that such-and-such firms could, if they would, turn over to sound-on-film, tape recording in one form or another, or what not. I have said it myself, and, while I think there is probably some truth in it, yet it is not the whole story. For one thing, there are too many disc machines in the world for them to be replaced at a touch; then imagine the state of a grand opera on reels of film in an average household, complete with children, after a few weeks. Then there is the matter of cost. We could doubtless have full symphonies or operas tomorrow on film at a price, but that price would be unquestionably prohibitive, and when one considers the difference in cost of processing a photographic record on many feet of film, plus the cost of the film itself and the enormous increase of time involved compared with the simple and speedy pressing of discs, it is easy to see where the advantage of the disc lies, and to some extent must probably always lie.

Alternative Systems

That being the position, what are the remedies or alternatives? It seems to me that the disc must retain its position as the chief source of recorded music in most households for a long time to come, but there is hardly one of the advantages which the old cylinder possessed that could not be incorporated in the disc without destroying its own inherent assets. It could be hill-and-dale cut, and is, in some cases; it could be played with a smooth stone or other similar stylus; it could have a mechanical traverse, thus relieving the record of more than half its work; it could still be pressed in the orthodox way but in some scratch-free plastic; and, finally, and most importantly, it could be made to play at constant linear speed. I harp-on this question of constant linear speed for the principal reason that it seems to me essential, if one is to get the most perfect reproduction possible, it is nonsense to expect to get precisely the same result from a given sound when at one moment it occupies about 3 in. of space and the next it is compressed into 1 in.

There are endless other possibilities by other methods, the outcome of which is pure speculation. Sound on film may yet sweep the board, but even that may not be as we now know it. The sound track may be excited to fluorescence by a special exciter lamp, or it may be made by some new magnetic system if some way of easy duplication can be devised, or, again, it may be by some entirely new electronic method. All I hope is that we shall soon cease to get our music by scraping a steel point carrying some tons of weight per square inch over what is virtually a refined macadamised roadway.

Microgroove vinyl appeared after the war and developed into stereo with two grooves at 90 degrees to each other and both at 45 degrees to the vertical but the CD took almost another 40 years before a 'game changing' technology appeared, and that was still an image pressed into plastic. The cassette tape was the only mass market use of magnetic recording and film never made it to the market. Curator.

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