Dear Editor (Apr. 1980)

Mike on MusicMountain

Dear Editor:

I want to congratulate Ed Canby for his marvelous detective work and nostalgic reporting of the Music Mountain concert and its recording techniques (Audio, November, 1979). I'm in a unique position to tell Ed and the Audio audience exactly how astute were his guesses about the miking and mixing techniques, for, you see, I am the recording engineer for Music Mountain.

By the by, Ed, it is a bit frustrating or me to be reading about myself in such an indirect way. I really would like to have met you, for I feel that I know you already through your writings. So, Ed Canby is invited to the Green Room any time next season at beautiful Music Mountain for the behind-the-scenes meeting that didn't quite occur this past year.

Well, did E.T.C. guess correctly what types of mikes were used at Music Mountain and how they were used? Not to keep you in suspense, the answer is, essentially, yes. That well-hid den and spaced rear pair of mikes are not omnis as surmised, but cardioids, pointed somewhat to help minimize the effect of the distracting audience noise that Ed describes so well. The object of these mikes is to capture the hall ambience. If the audience were not present, I would most certainly choose omnis for that role and hang them in the same "ideal" spot. Fortunately, there is enough random reverberation in that part of the hall to permit the use of the cardioids, which favor the musical ambience and lower the direct sound of the crowd 3 to 6 dB below that which omnis would have picked up.

The close, front pair are two mikes close to each other, as Ed saw. But (from his vantage point) he must have mistaken the cross bar of the stereo bar mike holder for one of the micro phones, for he surmised that the mikes were an M-S matrix. In fact, they are a crossed pair of cardioids at about 110 degrees (not 90 degrees) to each other, and with the capsules close together.

This is a sort of a cross between X-Y and O.R.T.F. techniques and works best at this distance from the quartet.

On home speakers optimally set up, the result will be a naturally appearing left-to-right image as if you were sitting in Ed Canby's ideal Music Mountain seat. By the way, if the setup were M-S matrix, the mikes would be at 90 degrees and one would be a cardioid facing front, the other a figure eight facing sideways, not an omni.

If (and I hope) Ed comes backstage later this year, then maybe we will discuss the custom mixing, taping, and monitoring equipment used to record Music Mountain. But at this time I've got to get back to preparing the tapes for 1979-80 broadcast. This year the concerts will be broadcast on the Eastern Public Radio Network, in the Mid west and West on a selected network, and in New York City on WNCN-FM.

I like to think that this method of re cording Music Mountain closely reproduces the musical balance and acoustic ambience that a visitor to a concert in Gordon Hall receives.

Bob Katz, New York City

Rating the Ratings

Dear Editor:

Last August I was given a promotional copy of Sparks' latest album, No. 1 in Heaven, along with assurance that I could turn it into an art project or something if I didn't like it. I had to agree with Jon Tiven's D+ performance rating in November's Column.

This week, a friend brought over The Eagles' The Long Run for me to audition, and Jon Tiven is (nearly) right again. I do, however, view his F+ rating as too severe. On the basis that the Eagles at least managed to produce what appears to be music on the al bum, consistency in rating would seem to indicate some increment above that accorded to Sparks' electronic noise.

-Frank Stephans; Durham, N.C.

Errata: Tonearm Geometry In the January, 1980, article "Tonearm Geometry and Setup Demystified," equation 4 (page 77) should read as follows:

Mounting center =

√ [L^2 + r1^2--2 Lr1 cos (90-a)]

Equation 6 (page 78) of this article should be:

Angular error = 90-OA - arc cos [[R^2+L^2 - L(L-OH)2] ]2RL]

(Audio magazine, Apr. 1980 )

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