an open-source digital signal processing and sound synthesis language
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PANECHO -- stereo echo with feedback
in RTcmix/insts/std

quick syntax:
PANECHO(outsk, insk, dur, AMP, CHAN_0_DELAY, CHAN_1_DELAY, FEEDBACK, ringdowndur[, inputchan])

CAPITALIZED parameters are pfield-enabled for table or dynamic control (see the maketable or makeconnection scorefile commands). Parameters after the [bracket] are optional and default to 0 unless otherwise noted.

   p0 = output start time (seconds)
   p1 = input start time (seconds)
   p2 = input duration (seconds)
   p3 = amplitude multiplier (relative multiplier of input signal)
   p4 = left channel delay time (seconds)
   p5 = right channel delay time (seconds)
   p6 = delay feedback (i.e., regeneration multiplier) [0-1]
   p7 = ring-down duration (seconds)
   p8 = input channel [optional; default is 0]

   p3 (amplitude), p4 (left delay time), p5 (right delay time) and
   p6 (feedback) can receive dynamic updates from a table or real-time
   control source.

   Author:  Brad Garton;  rev. for v4.0 by JGG, 7/10/04

PANECHO is a more complex stereo delay instrument than DELAY. PANECHO takes an input signal and "ping-pongs" the delays between the left and right channels.

Usage Notes

The input signal will first appear in channel 0 of the output after "CHAN_0_DELAY" seconds. This is then fed into the delay for channel 1, where it will appear "CHAN_1_DELAY" seconds after channel 0. This then feeds back into the delay line of channel 0 after being multiplied by p6 ("FEEDBACK"). Obviously p6 should be < 1.0.

The point of the ring-down duration parameter (p7) is to let you control how long the delay will sound after the input has stopped. Too short a time, and the sound may be cut off prematurely as the echoes die away.

Any amplitude control information coming through p3 will be applied to the audio input over the duration (p2) of the note -- the envelope will be finished during the ring-down period.

The delay lines are allocated based on the pfield parameters, so arbitrarily long delays are possible (at some point you use up available computer memory...)

PANECHO can only process one channel at a time; however two PANECHO notes (acting on different input channels) can work simultaneously. PANECHO assumes stereo output.

Sample Scores

very basic:
   rtsetparams(44100, 2)


   ampenv = maketable("line", 1000, 0,0, 0.5,1, 3.5,1, 7,0)
   PANECHO(0, 0, 7, 0.7*ampenv, .14, 0.069, .7, 3.5)
   ampenv= maketable("line", 1000, 0,0, 0.1,1, 1.5,0.21, 3.5,1, 7,0)
   PANECHO(4.9, 0, 7, 1*ampenv, 3.14, 0.5, 0.35, 9.5)

another basic score:
   rtsetparams(44100, 2)

   rtinput("AUDIO", "MIC")

   ampenv = maketable("line", 1000, 0,1, 100, 1)
   PANECHO(0, 0, 14, 0.9*ampenv, 5.14, 1.14, .7, 9.5)
   PANECHO(10, 0, 7, 0.5*ampenv, 1.14, 0.14, .7, 3.5)

See Also