Materials for a workshop on binaural audio and (you guessed it) live coding, with some "setup" examples to get started with SuperCollider and TidalCycles (SuperDirt).
For a higher-level overview of binaural audio, see the slides from our TOPLAP Barcelona workshop in November 2020, which were prepared and presented by Timothy Schmele. The workshop was a "three-hander", as Niklas Reppel also presented examples for live coding with binaural audio via a digital audio workstation and plugins, while Glen Fraser presented his SuperCollider and TidalCycles (SuperDirt) live coding workflows and the examples from this repository.
See README in the examples directory for help
installing the Ambisonic Toolkit (ATK) in SuperCollider. Or just
follow the very good
introduction and setup
in regular SuperCollider documentation.
The other README in the hrir directory gives a
few links for sites to find head-related (directional) impulse
responses, to use with the direct convolution approach.
Once you've got the ATK and some impulse response files installed, you're ready to dive into the examples.
If you use TidalCycles, try one or both
of the following setups. In both cases, the pan argument in
Tidal/SuperDirt uses 0.5 for forward centre, 0.25 for left, 0.75 for
right, and 0 (or 1) for behind.
- setup-superdirt-atk.scd
sets up panning (in a horizontal plane) using the
ATK in conjunction with
SuperDirt/Tidal's
panargument. - setup-superdirt-conv.scd works with eight audio outputs (could be real speakers or "virtual"), assumed to be in a circle. An output Synth is created to convolve with the directions of each output's "virtual speaker", producing a binaural stereo result on the first two outputs. This setup can also be used "just with SuperCollider", as it convolves the eight channels of output to produce binaural stereo, regardless of the source.
If you "just" use SuperCollider,
you can still try the setup-superdirt-conv.scd example, and output
whatever you want to eight channels (it can be reconfigured for
different number of outputs and/or speaker placements).
To go down a deeper rabbit hole with ambisonics, you may also try the
supercollider-atk.scd example,
which configures SC to have four audio channels. In this case, they
are not "to be played" as audio -- they represent the four channels
of first-order ambisonic B-format (omnidirectional on channel 0,
followed by directional spherical harmonics). A decoder Synth runs on
the final SC output, so any Ndefs or Synths played to the SC outputs
are assumed to be in B-format (should have been encoded using
FoaEncode), and will be decoded (by a Synth in a Group following
SC's default Group on the server) to produce binaural stereo.
If you want to experiment with higher-order ambisonics (2nd-5th order) in SuperCollider, you may try the SC-HOA Quark, now part of the normal Quark distribution. In particular, 3rd order (requiring 16 audio channels for the spherical harmonics) seems to be a reasonable "sweet spot", offering considerably more spatial precision without overly-heavy CPU processing requirements. To do: add an example using SC-HOA. Another option is to use the excellent VSTPlugin extension to instantiate VST encoding/decoding plugins -- such as those from IEM -- within SC Synths.
Niklas showed an alternative approach which can be used in live coding, using spatialization plug-ins running in a digital audio workstation. Audio sources are piped from SuperCollider to the DAW for binaural encoding/decoding there. Here are links to some tools shown in Niklas' part of the workshop:
- Anaglyph high-definition binaural spatialization plugin.
- BlackHole for routing audio between applications on macOS.
- SoundFlower as an older alternative for inter-app audio routing on Mac (old but may still work).
- IEM Plug-in Suite for ambisonic encoding, decoding, visualization and other effects.
- Reaper is the DAW Niklas was using.