International projectionist (Jan 1959-Dec 1960)

Stereo": What it is and What it Does The second in a series of definitive articles on stereophonic sound, as prepared by the Fairchild Recording Equipment Corp., 10-40 45th Ave., Long Island City, New York. IN ITS present state of development stereo sound is originally recorded in two, three or more channels on as many separate tape tracks (many major companies have been recording this way for several years and have a huge library of stereo master recordings). For the final recording, these channels are "mixed" and then put on two separate channels on one tape or, now, on a stereo disc. The playback is then kept entirely separate just as in the "binaural" system, but the final sound outlet is from two loudspeakers instead of from two earphones. The difference between listening to two loudspeakers as compared with listening through two headphones is that the observer does not have complete separation of the two channels with two loudspeakers. That is, his left ear will hear some of the sound coming out of the right speaker, and his right ear will hear some of the sound coming out of the left speaker, because of reflections from the walls of the room where he is listening. "Live Presence" Reproduction Since stereo reproduction is therefore less "pure" than binaural (although infinitely more practical and acceptable) it requires a little more artistry in the recording process, and this is just what the recording engineer must apply. So, he balances the various original channels in such a way that when played back through two loudspeakers, the sound will be most natural. This is not so hard to do, since he has available a playback system much like the one used in schools and homes. Perhaps it will now be clear why with stereo the effect is more like putting the orchestra into your area, since the acoustics will have some influence on the sound. Tli us far we have found that stereo requires two microphones and two separate recordings, and also two separate amplifying systems and two independ Content Enhanced by Technique The article beginning on page 5 of this issue is of particular import to those who appreciate the value of manner of presentation as well as content of a particular subject. We at IP feel that this is one of the most definitive articles ever published on presentation technique. cnt loudspeakers. It has the effect of eliminating the "keyhole effect" and of "opening up" the music so that the orchestra or the artist is brought right into the listening area, instead of having to hear it through a small opening, or even two small openings. Previously this has been possible only on tape recorders or by using both an FM and AM radio receiver simultaneously." Now what about stereo discs? The advantages of two-channel sound have been recognized for many years, but it has always seemed very difficult to achieve this kind of double recording without great complexity and expense. Tape recording supplied a relatively easy method of providing the purchaser two independent recordings (which is what two-channel recording amounts to) but there were many drawbacks. Expense Factor With Tape The principal disadvantage was, of course, expense, because a tape recording itself costs two to three times as much as an equally good LP disc recording. Also, many people do not own tape recording machines (although many own phonograph equipment) and it is, therefore, necessary to buy a fairly expensive piece of equipment in order to use a stereo tape. Although it may not be inherently necessary, it seems to be true at present that a good tape playback machine is rather more expensive to buy than equally good disc equipment. Another very practical disadvantage of tape is that in order to play back a tape with good quality, it is necessary to have the playback head aligned in the exact plane relative to the tape as was the original recording head. This is difficult enough even when playing back a one-track recording on the machine on which it was originally made; but when a dual-track recording is played back on another machine, this misalignment problem can be quite serious. It is something like the effect * FREQUENCY MODULATION (FM)— A method of radio broadcasting in which the broadcast waves change in length and their strength remains constant. AMPLITUDE MODULATION (AM)— The present standard method of broadcasting, in which the broadcast waves change in strength but the wave-length remains unchanged. WHAT FM DOES— Eliminates static, noise of electrical appliances and other disturbances that interfere with reception on AM radio receivers. It also permits reception of the entire range of sound audible to the human ear. that would be obtained in playing a phonograph record with a worn needle, or one too large or too small for the groove (except that tape head misalignment will not damage the tape recording, naturally). Re-Recording Quality Loss Still more problems are added when the original tape is not used but instead a re-recording, which naturally is exactly what a commercial tape recording is. In other words, each time the tape is passed through another duplicating process, the deterioration of sound because of head misalignment (and other factors, as well) tends to become more pronounced. Stated another way, as of today disc lends itself much more gracefully to mass production of quality. Since Fairchild makes both tape and disc recording equipment, as well as professional and home, or hi-fi playback equipment, it has no interest whatever in "talking down" tape systems. In fact, Fairchild developed and manufactured some of the first (and still among the best) tape recording machines for use by recording studios. Nevertheless, there are disadvantages in tape, as there are in all systems for doing anything of a practical nature. Another serious drawback to the use of tape is the difficulty of threading and handling it. No matter how well things are worked out, there is always the danger of tape spillage. Even if this were not so, the great disadvantage of not being able to start immediately at any desired point is a very real one. [TO BE CONTINUED] * * * University Degree by TV? Envisaging a plan under which state and regional TV stations would be linked in a nation-wide system that could cost $800 millions, John Ivey, executive vice-president of New York University, told the U. S. Senate Commerce Committee that such maximum use of educational TV could make it possible to get a university degree without attending school. Mr. Ivey plumped hard for a "much larger" sum in Federal aid for educational TV than the $1 million ticketed. Lecture System Predominate The TV student would need help from suburban discussion leaders and bookmobiles, he suggested, estimating that 85% of undergraduate instruction was carried out by the lecture system, which could be duplicated on tape. Mr. Ivey said the TV system would be superior because the student could hear top experts in each field. He said it could help solve the teacher shortage. 20 INTERNATIONAL PROJECTIONIST FEBRUARY 1959