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16 November 1964Mr. Robert A. MoogR. As Me Og CompanyTrumansburg, New York 146866Dear Mr. MoozsThank you for your interested reply. I have a bell gate and aring. modulator, but I would be very interested indeed in trying out abank. of oe as Bip d Rem ag Department has just @egked to have itsaudio genein reply to your questions about my greatest needs at the moment,I am supplying the following list (you asked for it!).1. An oselliator bank. Selfeexplanatory.A beand=pass filter. I heve examined various types of commercialfilters but cannot afford any of them. They seem to me to beoverpriced, especially since I"ve been told thet one can assemblea reasonable facsimile for about $50. I have not been able toLocate a schematic, however, and my math will not stand up to de-signing my own. Perhaps you know where I could obtain such aschomatic or else a reasonably priced kit.>> A Springer Zeiltmasse machine. Dr. Schaeffer has seen one of thesein Europe, but says it has only limited application. Basicallyit is similar to the Bell "Edispot". With it one can viiry thepitch of a particular envelope without affecting its length orduzvation, because of the rotating miltiple tape heads. I'd liketo "see for myself."A speed control device. I've read that an A.C. tape transportmotor ean be controlled by hooking wp a@ sine generator, a 100 wattbasic amplifier and a variable transformer. The generator suppliesthe 60 cycles and deviation from this will speed up or slow dowthe motor. I have a deck attached to a variable transformer. butae this only controls the voltage. I eam unable to do anything morenen slow ea tape dow. The range is very small and varies accordinghad "7 syiction involved. Usually. the best I can do is about aOtherwise I am limited to octave transposi--t40n. This te a very 'real handicap. Perhaps you can advise meIt seems to me that if this is a practical manner in which speedcontrol can be managed, someone ought to mut out e paeiiges wntimu which all these components are matched.A Prequency divider. I*ve budlt one of these, but it has only alimited use because it has to be reetuned for every other note.

Mr. Robert Ae MoogMovesber 16, 1964Pace Twoa frequency divider and/or miltiplier can be truly independentof frequency, this would be ea useful instrument for thickeninga lines and building spectra from pre-existent sources.I'd like to see a unit thet would contain both @ divider and aay which could be used interchangeably. Perhaps it couldmtein a control which would allow @ivision/mltiplication atGaareke other than the octeve,.Gosincidence and "Or" gates. I've seen diagrams of these in Elec�tronics texts, but have not experimented with item as yet. I beeEteverthese could be adapted for use by electronic music composers.I'm only ettessing, but I suspect that some of these instruments arealready used in Music Synthesizer computors. These gates could beuseful. For instance, if one has a rhythmic figure and wishes toe6d further sounds to it, the "and" gate wits simplify the process.I don't know how you would do it otherwise. except by a longsplicing process. New rhythms could be snenbad trim vabetine mateerial by mixing tape loops through the gate. Only when they allstrike @t once will a sound be passed.A soundeinto�light device. Dr. Schaeffer has one of these but I�id not have a chance to examine it. I heave been trying to setwo my own to use at a projected concert here at the college. Perehaps you can help me. It consists of a set of band pass filterswhich trigger small relays. The relays control a bank of coloredi@hte which are focused on a mobile�like collection of hangingmirrors, which in turn reflect the lights onto a screen. The screeneconeeals the whole device, which is hidden behind it. This hasnothing to do with the production of music, dbut it would give theaudience something to look at during a concert. I heave learned ofan instrument called the "Andio-Golor" made by CONAR (5939 WisconsinAvemme, Washington, D. C. ), but I assume it is om & smaller scalethan the one which I envision. I enclose a dlagrem of my idea.A Roythmic Instrument. I have seen diagrams of the Wurlitzer "SideMen" and the Baldwin "Tempo Mate" both of which ave electronic organsceessories designed to supply drum and trap accompaniments in avariety of dance rhythms. I have also noticed a machine called the"Belloti Trinome" (fang and Dinner Inc. abd N, Sacramento Avenue,Chicago) which is capable of clitking out a v variety of rhythms ("arhy thad c metronome"). I hmve also heard of a device called a'yhythmicon", an invention of the composer Henry Cowell on which anyKiar deere of pulkites may be obtained. I would like to have eninetrument combining all of these features which would supply avariable series of rhythms or a combination of rhythms at once.This instrument might consist of several electronic switches andmight also include noise generators and bell-drum gates. Theremight also be imputs which would allow the mixing or substitutionof exterior sound sources as well.

Mr. Robert A. MoogNovember 16. 1964Page ThreeA light-sensitive volume control. I have seen Dr. Scheeffer's"Hamograph" which accomplishes this. 'This is a device to con-ol sound rorya only, I believe that this instrument worksthis manner: light-powered | '@ arranged im such a wayto eut off an interstage tube by the application of a negative5�*>tsagecrFie)if =jas to the grid. An insertion between the light source and thewihinte cell reduces this bias (if that's the right term) allowingsound source to pass. Dr. Schaeffer's auve i Doge vera: c@lluloiadoy on which are pasted opaque pieces of cloth, shaped to formis esired envelope. I believe there prion be meat tents applyingto this instrument that might cause difficulties.fasa = a 2 otu*eliy, I am very interested in your seminar. I would Like toLLowiL ng manana ious � ased on my own experience.Fit "yo,4 jS he oeL. Unless you have a great deal of money for this project, itmight be wise to require the participants to supply their owncottonepicking tape. Free tape is just too mich of a temptation.8. Besinners incilities involvedI would consider operatine at least two studicthis idiom are often overthelned. by the possiband consume great quantities of studio time.I would encourage the participants to ine at much of theirown equipment as they can for the same reasor Much splicingand editing can be done independently if one has his own reecorder, thus saving studio time.I would be very interested in participating in this workshop, shouldyou care to consider me. As you know, there are several approaches to electro�nic music and you should include composers who represent the scientific com-putericed approach as well as the less learned but perhaps more practical side.I am preparing a detailed and annotated catalogue of my compositionsand the instruments I employ in my studio, which I will send to you in a fewweeks. If you know of any interested parties, I would be meh obliged fortheir addresses. I feel this account may be of interest especially to be-sinning composers as it traces my own development in this idion.Again, many thanks.Sincerely yours,Qheirman, Dept. of Music