Phonograph Monthly Review, Vol. 3, No. 12 (1929-09)

408 The Phonograph Monthly Review September, 1929 How to Make Your Records Last By “PETROS” Reprinted from the August issue of The Gramophone Critic, (London) I N THE old days of acoustical recording the problem of record wear did not beset the gramophile as it does at present, and many people are puzzled to know the reason why. It is not far to seek. Prior to electric recording a great deal of the music played never reached the disc, and thus the recorded sound waves were of a much simpler nature than they are at present. Now that the range of sensitivity of the record- ing apparatus has been enormously extended, and since it has become possible to amplify the vi- brations before conveying them to the cutting stylus, the convolutions in the sound grooves are not only far more complicated than they used to be, but they are also of greater amplitude, e.g., the sound is recorded far more loudly. The result of this is twofold. In the first place the needle has to follow a road with many more complicated twists and turns in it than for- merly, which offers greater resistance to the needle, and consequently more wear to the re- cord; and secondly these twists and turns in the sound groove carry it so much farther on either side of the central or mean position that one groove frequently almost cuts through into the adjoining grooves, with the result that the walls between the grooves are reduced to mere shells in these parts. This was seldom the case with the old records, and it should be clear to anyone that un- less a gramophone is very accurately made, and the needle tracks the sound grooves perfectly, it will very soon break down these thin walls and the first stages of record deterioration will have commenced. The foregoing are two of the chief reasons why modern records wear out quickly under or- dinary usage. But there are others. In order to reproduce correctly the very deep bass notes now recorded, the gramophone should possess a long exponential horn with a large opening, and the sound-box should be of the correct type and pro- perly tuned to the system of amplification used. If a gramophone is incapable of reproducing all the music on the record (and especially the bass), that part of the energy set up by the needle which is not converted into sound is reflected back to the needle again and expended in tearing up the record. This is cause No. 3. I think you will begin to realize now how im- portant it is to use a properly made instrument if you wish not only to preserve your records for a reasonable length of time, but also to hear them correctly. You will understand, too, that rapid wear of the new records is not absolutely inevi- table, as so many people seem to imagine. Old badly-designed gramophones, of course are chiefly responsible for the heavy death rate amongst the new recordings, but even some of the new ones are by no means guiltless. One very common defect in gramophone construction is bad needle-track alignment, and this is respon- sible for- at least 50 per cent of record wear. Un- less the needle points correctly along the track at all parts of the record, it will very quickly de- stroy the track, and this happens much sooner with modern records than with the old ones, for reasons I have already explained. Incidentally, the reproduction will suffer as well. Other essentials for perfect reproductions and the minimum of record wear are: An easy mov- ing tone-arm and a sensitive sound-box. If there is the least stiffness or binding in the former, this will impose a drag against one side of the sound track as it draws the tone-arm and sound- box inwards, and the increased friction naturally hastens the destructions of the track. In the old days sound-boxes were made with small stiff diaphragms and severely tensioned stylus bars. We have learned wisdom now, and in modern reproducers the diaphragms are both light and flexible and the stylus bars move as free- ly as possible. It does not need much deep think- ing for one to understand that if the sound im- pressions engraved on the record have to force a stiff diaphragm and unyielding stylus bar from side to side, the former suffer much greater de- struction in the process than when the stylus bar and diaphragm respond freely. Furthermore, the reproduction is naturally more accurate in all respects under the latter conditions. It is easy to test a sound-box in respect of free- dom of stylus bar and diaphragm movement. Quite a moderate effort exerted by the fingers on the needle holder should suffice to move the dia- phragm in and out to an appreciable extent. If considerable force has to be used in order to pro- duce any visible movement of the diaphragm either the latter is too stiff, or the stylus bar too tightly tensioned, or both these factors are op- erating together. Such a sound-box is bound to produce unnecessary record wear even if the rest of the instrument is O.K. If you are in doubt as to whether your gramo- phone is treating your records fairly, you can easily put it to the test by using fibre needles. A gramophone which plays through, say, a loud