Comments on "Talisman IV"

Jeffrey Hall

tal4.orc tal4.sco

"Talisman IV" is the 4th piece of a series which I began in the mainframe environment of the late 1970s and early 1980s, at Columbia and Princeton Universities.

"Talisman", the original work from that time, formed a part of my Columbia dissertation which was completed by December of 1982 and defended in June of 1983. Subsequently, the dwindling of institutional support delayed my return to digital music for 15 years, during which time I focused my energies on composition for acoustic media, teaching, and ancillary theoretical concerns.

By June of 1998, the power of the new personal computers and the acquisition of my own system enabled my return to digital music via Csound, a privilege almost incomparable in the shadow of my work with mainframe systems, wherein the turnaround time alone was an enormous obstacle to productive composition.

Consequently, "Talisman II", and "Talisman III" were completed with Csound in April and November of 1999, respectively.

I hope to complete "Talisman V" by the end of the coming summer, and with its completion, put an end to the four pieces from II through V, calling the collection of pieces "Earmovie I". The collection is not a haphazard compilation, but rather a concerted effort to compose a series of sequentially related pieces which utilize evolving patterns, motives, themes, and even "Leitmotiven", throughout, and which series, I like to think, might be imagined as the equivalent of a kind of aural "film noir" from an imaginary planet in a remote galaxy which long since has been turned into interstellar dust.

It is in the light of this history then, that I offer the code of "Talisman IV", with the understanding, or at least indulgence, of my colleagues, in the comprehension that the instruments and procedures involved are the Csound descendants of their M360 counterparts from so long ago.

That said, I should relate that the conception and design of "Talisman IV" were from the outset determined by my desire to write a piece that could be contained entirely within the Csound code, which is to say, that I wanted to write a piece that did not call on adventitious sound files, or involve the use of editor software. The motives for that desire were not only the resulting ease of portability, but also the goal of ultimately controlling all score inputs in terms of the piece's compositional syntax, which goal, I must readily admit, is only in the incipient stages of its realization, but which nonetheless continues to enchant my efforts in digital music.

In essence, then, what continues to tantalize me is the capacity of a Csound program to harmonize the synthesis with the patterns and textures which arise spontaneously from my imagination, with the important caveat that my imagination is sometimes surprised by the unintended, and at times useful, products of the programs themselves, a result which, in effect, comes from my having "outwitted myself" (the immortal words of C.M. Dodge).

The orchestra then, is an ad-hoc construction written from scratch and which also was written, not for export, but simply for the purpose of realizing the piece. As a consequence of this, the code is sometimes redundant, a fact for which I ask for tolerance rather than pardon.

Beyond that, to try to explicate the entire orc would entail writing a large essay which I think would go beyond the scope of this publication.

That said, I should at least try to give a quick overview of the orc and what it is supposed to do:

Group 1 - Instrs using the fof opcode: 1,6,19,& 20; 13 & 14.

Instrs 1,6,19, & 20, are replicates of a fof instr which has a little bit of fm and whose fof ugens are concatenated in an amp ratio derived from the Fibonacci series.

Instrs 13 & 14 are a close variant of instrs 1, 6, etc.

Group 2 - Instrs using resons to filter white noise: 21 & 22; 2,4,15 & 16; 3,5,17 & 18.

Instrs 21 & 22 are a truncated variant of an old filter/additive instr which utilizes fibonacci ratios for the center frequencies of the filters above the octave of the fundamental. The octave of the fundamental is there to support the definition of the center frequency. The source being filtered of course is white noise. In dense and overlapped textures this instr can evoke the sound of a chorus.

Instrs 2,4,15, & 16, are a variant of instr 21, but with added fm (my own patch - see Group 3).

Instrs 3,5,17,18, are a variant of the original filter instr which was used for instrs 21,22, and also 2,4,15,& 16. The source being filtered is white noise. This is the complete old instr but with changed functions and envlps, so it becomes a kind of pitched gong instr, and with different amps and envlps can sound a bit like a marimba. This instr also has a patch which yields transpositions, inversions, or transposed inversions. It was implemented to manipulate the massive blocks of percussive articulations. This version of the patch was adequate for this piece, but was a little sloppy in its octaviation. Consequently I doped out a version which will invert and transpose while preserving the original contours of the line so that, with a little tweaking one can get a transposed mirror inversion of the original line. I would prefer to share this later upgrade rather than have someone try to use the version presented here.

Group 3 - Instrs using my own fm patch (i.e., not the opcode): 7,10,26 & 27; 24 & 25.

The patch is derived from study of the original Chowning article from "The Journal of the Audio Engineering Society" Volume 21 Number 7, September 1973, and Russ Pinkston's chapter in his rewrite of the old M360 manual. Instrs 7,10,26, & 27, are a variant of a horn-like fm instr from "Talisman II". The fm again is derived from the Chowning model. Given different amps and frequencies, this instr quickly can turn into a woody-sounding percussive instr. This was implemented herein by setting pitches in simultaneous instrs to trichords and hexachords ( i.e, 0,1,4, & 0,1,3,4,7,8) which have a generative role in the piece's structure.

Instrs 24 & 25, are an fm instr with a double modulator and double carrier. The fm is also derived from the Chowning model. This instr is adequate for its use in this piece, but I think it still needs a lot of reworking.

Group 4 - My own simple alpass reverberator

Instr 9 is a very simple alpass reverberator which is used sparingly to "highlight" certain percussive articulations of the instr 7 family. There is very little actual reverb in this piece, if only because the use of reverb sometimes can seriously smear counterpoints and textures to the point of unintelligibility. One way around that problem which way was used in this piece is the use of durations which are prolonged considerably beyond the following starting time. This worked best in the percussive groups wherein I could exploit the high onset amps and low decay amps so that the instr's overlapping decay time can dwindle into an echo, thereby sounding a lot like reverb but not smearing the attack times of the other instrs. This still needs to be handled with care because the prolongations can concatenate and obscure the texture to the point of blurring, an effect not unlike the smearing of long reverb times and high degrees of echo density.

Articulations within notes in all these instrs entail pitch fluctuations which are intended to act as proxies for vibrato. Sometimes the semblance does approach vibrato, and at other times it becomes more of a general fluctuation. When the durations grow shorter the fluctuations destabilize the center frequency, to the degree that it can be up to 20 cps off the input frequency. I found that I preferred this imprecision to having the input frequency always come out "dead on" pitch.

I am sharing this work at the urging of friends who have told me that others might find ways to utilize and profit from my efforts. I am happy and flattered to have this opportunity and think that the spirit of the Csound community more than deserves both my gratitude and modest tribute. Consequently if anyone would like to use all or part of these instrs, please feel free to do so providing that if you share it, do leave some space to credit me in the header.

Finally, I would be remiss were I not to express my gratitude to a long list of teachers, friends, and colleagues without whom I would have gotten lost. They include, but are not limited to: Charles Dodge, Maurice Wright, Mark Zuckerman, Russ Pinkston, Paul Lansky, Milton Babbitt, Chou Wen-Chung, Edgar Williams, Dan Gutwein, Josep Comajuncosas, John ffitch, Richard Dobson, Richard Boulanger, Hans Mikelson, and all the list members who shared ideas, tips, and advice.

Jeff Hall