Category: csound

Eulerroom Equinox: Live Code Performance

I had the great pleasure to perform as part of the Eulerroom Equinox live coding event yesterday. It has been an amazing four days of live code streams from around the world and I’m grateful to the organizers for their incredible work putting this all together. Bravo to everyone and thanks to all of the incredible performers and presenters, very inspiring!

Sound Design: Ring Mod with low-frequency modulations

Audio example of Ring Modulation with low-frequency modulations
Csound Code + MP3: ringmod_modulations.zipDownload

Experiments with complex ring modulation and low-frequency modulations for sound design. Each ring modulation generates sidebands for the previous signal and with four ring modulations up to 16 frequencies could be generated. Modulating with ring modulation leads to interesting, synthetic sounds due to the ratios of frequencies changing over time. Having multiple orders of ring modulations allowed for interesting patterns of spectrums to develop (see spectrogram).

Spectrogram from Audacity (2048 bin size, 0-16000 Hz, linear)

This example has two instruments, RM1 and RM2. RM1 uses exponential envelopes to start and end at harmonic ratios but has different rates of change due to different starting ratios. (Mentioned here as ratios since the outputs are being used to multiply the p4 base frequency.) RM2 is a variation on RM1 and uses a sawtooth LFO for one of the modulations. Both use a high-pass filter to remove frequencies generated below the base frequency.

The score plays a pattern with RM1 twice, once with 0.5 durations and again
with 0.25 durations. This sounded to me like they could be used as a simple
laser sound in a game or as a component of more complex laser sound design. The score then has a 20 second long note for RM2 that gives it enough time to hear the evolving frequency patterns.

Sound Design: FM with Modulations

Audio Example of Complex FM sound with modulations to indices
Csound Code + MP3: fm_with_modulations.zipDownload

Complex FM (4 operator, what Chowning and Bristow calls Parallel Carrier,
Independent Modulator in “FM Theory and Applications”). The two operator stacks are using 4:2 and 1:1 C:M ratios. expseg envelopes are used to modulate the overall shape of indices and unipolar square lfo’s are used for an additional layer of modulation. I thought the 12 and 3 Hertz for the lfo’s gave some nice texture between the two layers.

I think it probably works best in the low end to middle of the frequency range. The result using pch of 5.00 reminded me of things heard in some progressive house tracks.

randcubic glissandi: random line with cubic interpolation

Audio example of randcubic used for glissandi
randcubic_glissandi.zipDownload

Custom Csound user-defined opcode randcubic to generate cubic interpolated lines. Example above uses randcubic for achieving time-varying glissandi with multiple voices.

Based on code from http://paulbourke.net/miscellaneous/interpolation/.

Code for UDO is as follows:

opcode randcubic, a,kk
  kamp, kfreq xin
  
  ky0 init random:i(-1, 1)
  ky1 init random:i(-1, 1)
  ky2 init random:i(-1, 1)
  ky3 init random:i(-1, 1)  
  
  kcount init 0
  asig init 0
  
  kperiod = sr / kfreq
  kndx = 0
  
  while (kndx < ksmps) do
    ka0 = ky3 - ky2 - ky0 + ky1
   	ka1 = ky0 - ky1 - ka0
    ka2 = ky2 - ky0
    ka3 = ky1
    
    kmu = kcount / kperiod
    kmu2 = kmu * kmu
    
    asig[kndx] = ka0 * kmu * kmu2 + ka1 * kmu2 + ka2 * kmu + ka3
    
    kcount += 1
    
    if(kcount > kperiod) then
      ky0 = ky1
  	  ky1 = ky2 
  	  ky2 = ky3       
      ky3 = random:k(-1, 1)  
      kcount -= kperiod
    endif
    
    kndx += 1
  od
    
  asig *= kamp
    
  xout asig
  
endop
Published
Categorized as csound Tagged

Live Code: 2019-08-14

Live code session using left-shift patterns and double modulus constraints.

(First time using OBS on a new Mac, video is slightly behind the audio…)

Hidden Laws

Completed: 2019.07.11
Duration: 7:55
Ensemble: Electronic (Blue, Csound)

MP3: Click Here
OGG: Click Here
FLAC: Click Here
Project Files – Click here (.blue, .csd)

A quiet meditation developed using four processes made up of bit-shifting and bit-masking operations. The rules, or “laws”, of each process are not complex on their own but together create an intricate texture and rhythm.