My {Audio Processing} Mailbox

A programmable digital box for live sound processing

Isaac Rufus Rosen-Purcell starts building an enclosure for an Axoloti Core
Isaac Rufus’s finished enclosure for the Axoloti Core

What it is for

My Audio Processing Mailbox is fully re-programmable as to give me access and compositional control over the digital processes effecting the sound. This enables me to program the parameters of the sound processing for every specific composition, venue, and performance.

How I came to the idea

I came to the idea of building a programmable pedal after I had put together an electronic pedal set-up for my clarinet. My original set-up used a volume pedal, delay pedal, and amplifier, as well as a PiezoBarrel pick-up that screws into a modified barrel of my clarinet. With the amplification, I was able to create a myriad of subtle sounds from the clarinet that would not normally be easily heard. I was then able to weave these subtle noises together with more familiar tones of the clarinet into new compositions, improvisations and comprovisations, using the delay pedal to create overlapping textural worlds.

Isaac Rufus’s digital Audio processing Mailbox all wired up with Axoloti core, potentiometers, shift registers, buttons, and LEDs
Isaac Rufus’s Axoloti Core with an added header

The Axoloti

I built this box using a Axoloti, which “consists of both hardware and software which work together to provide a virtual modular environment.
With the Axoloti software we can create ‘patches’ which are uploaded to the Axoloti hardware and then run on the hardware.”
, as described by the user thetechnobear in the user guide of the community forum.

Isaac Rufus’s first patch for the Audio Processing Mailbox
Isaac Rufus’s control sub-patch that links all the controls on the Mailbox to the patch

The First Patch

10/15/2019 – The first patch that I am working on expands what I was already doing with my old delay pedal. So far the patch consists of two independent delay channels. That means that the length and decay of two sound samples can be set separately. I want to be able to link and un-link the delay parameters. I am also working on adding harmonizers. The goal with this patch is to be able to create longer textural pieces with added contrast and cohesion between movements or worlds of sound.

Isaac Rufus’s two-channel delay sub-patch

Future Uses

I have added nine stereo jacks for expression pedals and/or other forms of control devices. When one of the jacks is in use, it bypasses one of the knobs, and sends information directly to the board. I plan to use this for multidisciplinary performances, where for example a dancer has pressure sensors on their feet. These sensors would send information to the box via one of these inputs. By programming the box, this information can control a parameter such as… let’s say pitch, or any number of parameters.

Isaac Rufus’s Audio Processing Mailbox’s inputs and outputs

A photo gallery of the building process