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Q. In April, a reader asked whether it would cause any undesirable effects to attach a phono cartridge to a headshell with silicone rubber cement. It seems to me that, because of the compliance of the silicone, he is creating a resonating circuit in series with the stylus-arm circuit, although at a higher frequency, in the audible range. -Gary Groves [no address given]. A. While it is true that any compliance/mass system creates a resonance, there should be negligible compliance in a secure mounting achieved as described in the earlier item. But if the cement is excessively thick or the bearing surfaces of the cartridge and/ or shell too restricted (making the mount ing insecure), undesirable resonance could occur. Q. I understand the functions of equalizers, dynamic range expanders, time-delay systems, and noise-reduction units, but I am unsure as to which would produce the most noticeable sound improvement in my basic system. Given my interest in rock music, derived equally from records and non-Dolby FM, and my equipment (Pioneer SX-1010 receiver, Accutrac 4000 turntable, and two B.E.S. d-50 speakers), which add-on signal processor would be the most worthwhile first choice? -Gerard E. Michel, Vandalia, Ohio. A. It would be as difficult to match you up with the right equipment as it would be to match you with a mate. But since you've told us a bit about yourself (and the selection being less crucial to your happiness than a human add-on), we'll attempt the role of marriage broker. Considering your first love in music-rock-we suggest an equalizer as a first choice. Our decision is based on a process of elimination. Since rock music is so highly compressed, noise seldom is a problem. So, we'll put the noise-reduction system fourth on the list. A range expander might be nice to expand some of the compressed rock to more realistic levels-but then, it wouldn't be the rock we all know and love. Put that in third place. That gets us down to the equalizer and the time-delay system. Knotty problem. We've had a lot of fun adding pseudo-concert-hall ambience to classical recordings with a time delay. We've also gotten some interesting hype effects with rock. But rock is hype enough as it is. Put the time delay in second place, and go for the equalizer. It's the tonal balance of rock that strikes us as needing the most homework, and we've yet to hear a speaker that couldn't stand a little equalization. Q. My cassette deck, a Teac 450, is hardly new, but I'm very fond of it and get excellent recordings from it. Yet when friends whose equipment is at least as good send me tapes they've made, the results can sound awful on the 450. The problem seems to be Dolby tracking since the levels come out very low on the Teac (though one channel generally is worse than the other), and the sound is muffled. Why should this be? -C. G. Lehrer, Springfield, Mass. A. There may be differences in head-height adjustment (its relationship to the tape's width), possibly compounded by other factors. Assuming that your Teac has been checked out by a competent repairman, he could touch up bias, recording level, metering, and so on, but head adjustment is trickier. Azimuth alignment tapes (used to adjust the head gap's perpendicularity to the recorded track), even from reputable suppliers, may not agree, and severe azimuth differences can contribute to muffled sound. Head height is even more of a problem, since all of the standard quality test-tape brands are recorded across the full width of the tape and allow no clue to misadjustment. If the 450 isn't "reading" along the paths that the recording head laid down, the overall output drops, affecting Dolby tracking. If one playback-head element is picking up some of the other channel's track, its output will drop less. Unfortunately, there's little a home user can do to ameliorate the effect. Q. While playing LPs I am frequently bothered by distortion that becomes most noticeable on the innermost grooves [IGD]. It seems to occur most often on recent pop/rock issues, usually during loud vocal/choral passages. It becomes especially noticeable when the signal is routed through a Sansui OSD-1 synthesizer, which seems to reproduce it as the major signal in the back channels. The turntable, a Sony PS-1800, has been checked by two clinics with both Shure V-15 Type Ill and ADC Super XLM Mk. II cartridges. Am I experiencing tracking or tracing problems? How can I tell if the distortion is inherent in the recording? What playback equipment (such as a straight-line-tracking arm or a Shibata stylus) would noticeably reduce this distortion? -Gary Handova, Silverado, Calif. A. Distortion is greatest on the inner grooves of a record [IGD], where the linear groove velocity is least. And high-level, high-frequency signals are most prone to this type of tracing distortion. Assuming that your turntable is functioning properly and that the cartridge is mounted with the correct overhang, you've pretty much done all you can do. A Shibata or other multiradial stylus generally will be able to trace these short wavelengths more readily than an elliptical because of its smaller scanning radius, but there are some records that just can't be played successfully. Q. My '77 1/2 Porsche 924 has a dealer-installed Blaupunkt AM/ FM/cassette deck with a three-speaker arrangement that appears to be wired with the front and left-back speakers reproducing the left channel and the right-back speaker handling the right channel. The sound just doesn't compare with that of a conventional two- or four-speaker arrangement. What are the advantages or disadvantages of my hookup, and what would you suggest for upgrading? I would prefer to interfere as little as possible with the factory installation. -John D. Frye, Baltimore, Md. A. Since most cars carry no passengers much of the time, the stereo balance should, if anything, be shaded to favor the driver; in your arrangement, it appears, only a passenger can expect reasonable balance. The easiest fix probably would be to move the leads for the center speaker from the left-channel amplifier terminals to the right-channel connections. Of course, if the Blaupunkt has a mono output, the obvious choice would be to drive the center speaker from it. ---- We regret that, due to the volume of reader mail we get, we cannot give individual answers to all questions.--- (High Fidelity, Oct. 1979) Also see: Jensen speakers (ad, May 1981)
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