PERFORMANCE NOTES for GEMINI NEBULA LIVE by Dave Seidel (2005) - live performance realizations by Art Hunkins. Gemini Nebula Live is a live-performance rendition of Dave Seidel's The Gemini Nebula for Csound. The original scorefile, along with recording and commentary, can be found at http://mysterybear.net/article/9/the-gemini-nebula. Study of these source materials is highly recommended, as live performance of Gemini Nebula Live is intended to model after the original work. The Gemini Nebula was composed in Csound, a software sound synthesis program; and Gemini Nebula Live is performable in several current varieties of Csound. These versions, all free downloads, are: Maldonado's CsoundAV (http: www.csounds.com/CsoundAV), Lazzarini's MyCsound4 (http://www.nuim.ie/academic/music/musictec/csound) and Ramsdell's csoundgbs/flCsound (http://sourceforge.net/project/showfiles.php?group_id=81968) - both console and simple GUI (flCsound) mode. All three Csounds are prebuilt for Windows systems; the last is also buildable (as console or simple GUI) for Linux. The *quad* versions of Gemini Nebula Live are currently *only performable on CsoundAV* (and, of course, require a multi-channel sound card). The performer must enable his/her chosen Csound "variety" under CsOptions in the selected Gemini Nebula Live performance (.csd) file; any other options must be commented out by inserting a semicolon at the beginning of their line. Gemini Nebula Live is demanding on system resources; therefore, a fairly powerful CPU is required to perform it without sonic interruption. (Minimizing programs running in the background will also be helpful.) The most responsive and bulletproof performance version of Csound is CsoundAV (Windows), and it is the default. In comparison, the other Csounds feel sluggish, though on faster systems their response time (also called "latency") can be improved by inserting the flag -b1000, as indicated in the performance file (under CsOptions). If doing so makes the sound choppy, substitute values for -b progressively up to 4000, until the choppiness disappears. Currently, Macintosh builds of Ramsdell's csoundgbs (as well as Ingalls' MacCsound) experience problems handling the (FLTK) graphics of Gemini Nebula Live or realtime audio, and so cannot perform it. Several other builds for Linux also will perform at least some versions of Gemini Nebula Live: Gogins' Csound5 - part of his CsoundVST package (http://sourceforge.net/project/showfiles.php?group_id=81968) and Varga's Csound-4.24.1, a prebuilt Linux binary (http://www.csound.com/istvan/html/cspatches.html - Varga's Windows binary will not work). Limitations of the various Linux packages are that they *may* not be capable of MIDI or (alternatively) of multi-channel audio. CsOptions flags (see above) are similar to those for MyCsound4 and csoundgbs/flcsound, except that the audio output device flag (-o) must be specified in a way unique to Linux. The performance model - following the original The Gemini Nebula - can be described as follows: tones (sine waves) are always paired, fading in and out as "intervals." The first interval, an outer "frame," is an octave; the second to appear is a combination of M2 and m7 within the first - an "inner frame." At the end of the piece, these same intervals fade out in reverse order. In between, sets of microtonal intervals - five within the lower M2 and five within the upper M2, gradually enter - until all tones are present - then exit. Although the general entrance order is low to high (and exit the reverse), the interval *pairings* on entrance and exit are different: on fade-in, the lowest tone within the low M2 is paired with the lowest in the high M2, etc. On fade-out, the microtonal *"twins"* are paired (those within the high M2 preceding the lower ones). All the microtonal pairs are separated spatially - extreme left and right. The overall effect is that of buildup of texture and intensity, featuring beating (in stereo) among the accumulating microtones. Important: please consult the original to get a sense of timing and duration for the various events. (All entries and exits are evenly paced and gradual.) Play time of The Gemini Nebula is 7.5 minutes; performance of Gemini Nebula Live should take about the same length, but could be somewhat longer or shorter depending on the choices of the performer. In the Live versions, there exists an option to fade the two "frames" in and out together rather than separately. In either case, these are to be the opening and closing events. The entry and exit order of the other, microtonal intervals is determined by the performer. The only constraint is that no tones may be omitted. The performer must realize that tone pairings - corresponding to performance controls (on-screen buttons or MIDI pots/sliders) - change once all the controls reach their maximum, and change back when (at the end) they all reach zero. Thus the fade-in and fade-out pairings are different. For this reason (and to facilitate rehearsal), a handy "All (Notes) Off" button is included in the non-MIDI versions. There are six different versions of Gemini Nebula Live. They differ in number of channels, by performance instrumentation and features. The two most basic variants are stereo, the remainder (with title suffix "4") are quad. Several versions use on-screen windows and mouse only; some (identified by suffix "M") require 12 MIDI continuous controllers (rotary pots and/or sliders - configured as one "bank" of eight and another of four). The "+" versions (quad only) make use of additional spatial options. All versions include an option to specify maximum levels for each tone pair. (Level is cumulative; the highest point should be only moderately loud.) In addition, the *quad* versions allow the performer to preset the symmetrical x-axis (left/right) spacing of pairs of tones. The "+" versions permit this - as well as a random start position option - on the y-axis (front/rear) as well. In quad versions, once the microtonal pairs reach maximum level, they randomly begin to wander (slowly) between front and rear. In the MIDI versions, be sure to turn all pots/sliders to zero before running the performance file. (Otherwise tones may initialize as "on" - which is not desirable.) Specifics of the individual versions follow. Gemini Nebula Live -- All performance is from an on-screen window with mouse click. 12 On/Off buttons for tone pairs. Variable Fade Time (can be preset or changed per note on/off). Presets for max amps and symmetrical pan position for tone pairs. This version most closely parallels the original The Gemini Nebula. Stereo. Gemini Nebula LiveM -- 12 external MIDI continuous controllers (rotary pots and/or sliders) determine amplitude of tone pairs. One "bank" of eight and one "bank" of four pots/sliders. The first controller number for the set of eight contiguous numbers of the bank must be specified on the performance screen prior to performance. The same for the set of four. (This selection is made to correspond to options available on your MIDI device; locate series of eight and four consecutive controller numbers on the device - or a single set of 12.) Otherwise same as Live above. Stereo. Gemini Nebula Live4 -- Same as Live above, except quadraphonic. All performance is with mouse in on-screen window. Includes option to Center tone Pair 1 (both tones in center) or Space them (.85 and .15 front placement). Pair one is extreme front; pair two is extreme rear (hard left and right). All other pairs start midway on the front-to-rear (y) axis, and after entering, randomly wander slowly between front and rear. All microtonal pairs (3-12) are also preset as to their symmetrical spacing on the left-to-right (x) axis. Requires multi-channel sound card. Gemini Nebula Live4+ -- Same as Live4 above, except for additional choice regarding y-axis start position for microtonal pairs. A button preselects either Random Y Position Start for these pairs (can be varied per entry) or user-determined Y Pan Preset location. (After tone pairs fade in fully, they randomly wander - as in Live4.) Requires multi-channel sound card. Gemini Nebula Live4M -- Combination of the features of Live4 and LiveM. Requires 12 continuous MIDI controllers. Requires multi-channel sound card. Gemini Nebula Live4M+ -- Combination of the features of Live4M and Live4+. Requires multi-channel sound card. Dave Seidel - dave at mysterybear dot com http://www.mysterybear.net/ Art Hunkins - abhunkin at uncg dot edu http://www31.brinkster.com/abhunkins February 2005