Dialogue de l'Ombre Double (1985; produced at IRCAM). This piece in its published form is performed by one clarinetist accompanied by a tape of the same clarinetist. The live and tape sounds are variously processed by an artificial reverberator, a ``piano reverb" (made by playing the sound through a loudspeaker underneath a piano whose sustain pedal is held down, and capturing the string resonances with a microphone), and six-channel panning in a variety of patterns.
According to folk tales around IRCAM, Dialogue was originally conceived as a piece for two clarinetists, one offstage who would play the sections of the piece which finally ended up as the tape part. The tape part's spatialization features very quick changes which would require score following to synchronize with a live clarinetist, and it was apparently at least partly for this reason that the offstage clarinetist was replaced by the tape. The tape also sent a synchronization signal to a sequencer controlling an array of VCAs to spatialize the tape.
This is a new, two-clarinet realization of the piece, using automatic score following to synchronize the spatialization with the offstage clarinet. This realization also includes a comb filter array that imitates the piano reverb effect. Although it does not replicate the effect exactly, it exhibits the same sort of tuned resonance that the piano does. (The piano reverb effect is by far the trickiest aspect of producing this piece. The piano must be placed in an acoustically quiet room that nobody can enter during the performance, and the speaker and microphone(s) must be carefully placed to avoid feedthrough without sacrificing sound quality.) I think the new effect is true enough to the intention of the piece that it can justifiably be used in performances; whether to use the electronic version or a real piano should be up the the discretion of the presenter.
The overall concert configuration is as shown here:
There are three components marked "optional". First, the piece can be played with or without the second clarinetist (who can be replaced via playback from the PC's disk). Second, the "piano reverb" may be done with a real piano, or imitated by the patch. Finally, the score calls for the tape clarinet to appear, at the very end of the piece, from a seventh speaker; if using a real clarinet, and if the real clarinet is placed so that he or she is barely audible without sound reinforcement, this speaker may be omitted.
A block diagram of the patch appears below:
(See also the general performance instructions .)
NOTE: The patch provided here is adapted from one that was used in a 1996 performance with Patrick O'Keefe and Robert Zelickman on clarinets. That performance used outboard gear and isn't practically recreatable now. The patch included here has been extensively revised (to remove the machine dependencies) and has not since been tested in a live performance. It will probably at least be necessary to adjust levels specified in the various qlists.
Dialogue may be played in two versions, called "Roman" and "Arabic"; they are essentially the same, except that the sections appear in a different order. This patch adopts the "roman" order. The sections are laid out as:
sigle initial (patch section 1) strophe I (2) transitoire A strophe II (3) transitoire B ... strophe VI (7) sigle finalThe patch has 7 sections; all but the first are intended to cover one "strophe" and the following "transitoire" (or, for the seventh, the "sigle final"). Two of the strophes use "piano reverb" on the live clarinet; the others use no electronics on the live clarinet at all.
Each section after the first starts automatically when the previous "transitoire" or "strophe" finishes; there is a built-in two-second delay before the piano reverb is started and whatever was active in the previous section is turned off. Each section after the first starts with score following turned off. Thus the person running the patch has to hit the "next" button once toward the end of each strophe to turn score following on and start the transformations for the next transitoire or sigle.
One of the strophes calls for piano reverb which only enters at certain points in the clarinet part. This is done manually at the mixer. (The score follower only operates on the offstage clarinet.)
As delivered the patch assumes that the offstage clarinet is live, and that the "piano reverb" is to be done electronically. The patch makes no assumption about whether there is a speaker 7 or not; a signal appears on output channel 7 which you may use or ignore as needed.
To use a recorded clarinet instead of a real one, you only have to play a stereo recording of the offstage clarinet through the patch (the score calls for separate "near" and "far" microphones.) The patch has its own disk recorder which you may use if you wish; it may be desirable to adjust the qlist to start the recordings where needed; alternatively, you could add manual controls to the patch.
A real piano reverb may be substituded by setting the variable "use-real-piano" to one. (You could set it to one at the beginning of each qlist for instance.) Doing this turns the comb filter array off and puts the piano send on audio output number 8, which should go to a speaker under the piano. The piano mic should then go to input channel 4. You may wish to adjust the "pno-level" values in the qlist accordingly.