# 9 ways to NRT, part 6: Generative techniques with NRT and Csound


Welcome to Part 6 of 9 Ways to NRT!

At this point, I've gone through many ways to translate NRT notation into useful formats, but I haven't yet shown how NRT can be used as composition tool for algorithmic and generative music. Today I wanted to write a simple generative music program using NRT and Csound.

The file below is a relatively simple pluck instrument I designed. Since we will be generating a corresponding score file, I've decided to do away with the monolithic format of the CSD and just use an oldschool .orc file. Save this file as plucker.orc:

sr	=	96000
ksmps	=	1
nchnls	=	2
0dbfs	=	1

instr 1 icps = cpsmidinn(p4) ;random amplitude iamp = random(0.2, 0.25) ;a pluck using a saw a1 pluck iamp, icps, icps, ftgenonce(0, 0, 4096, 7, 1, 4096, -1), 1 a1 *= linsegr(1, 1, 0) ;scoop out the low end a1 = buthp(a1, 300) outs a1, a1 endin

Now for the note generation. I'm using a mixture of awk and bash for my needs. The algorithm creates some nrt code by randomly stringing together smaller fragments of prewritten phrases in NRT. This code then gets sent to AWK where it is turned into a Csound score. The Csound score is then read and compiled to a wav file.


#collection of NRT fragments cluster=(


#randomly string NRT fragments, and generate score for i in $(seq 1 4) do

nrt=$nrt${cluster[$RANDOM % 4]} 


echo $nrt | nrt -F ' ' |\ awk -vtempo=$tempo ' BEGIN{ ts = 60 / tempo max = 0 } {

 print "i1",$1 * ts,$2 * ts,$3 + 60;
 if($1 * ts + $2 * ts > max) {
     max = $1 * ts + $2 * ts

} ' > score.sco

#render wav file csound -o out.wav plucker.orc score.sco rm score.sco

When this code is run, it creates a file called "out.wav", which can sound something like this