What is the Aristocrat?
The Aristocrat is a guitar pedal designed by DIYDSP. It is DSP (Digital Signal Processing)-based and programmable. The Aristocrat is based on the Audio Codec Shield from Open Music Labs and the Maple from Leaf Labs. It is called the Aristocrat because it can go anywhere and do anything.
It means you can download, modify, write and share programs to make audio effects for your guitar and other electric instruments (C64 bass?)
- You don't have to spend money on new guitar sounds when you want to try them out.
- You can customize the software in your pedal to suit your preferences.
- You can experiment with sound algorithms that aren't known yet or aren't commercial.
DSP Programming Resources
This is a collection of places to get information on how to write DSP-based effects:
Start with the Open Music Labs' forum on the Audio Codec Shield Open Music Labs is the supplier/designer of the Audio Codec Shield which is the best peripheral for an experimental electronic musician to have
It provides a pair of stereo, CD-quality (16-bit 44.1kHz) inputs and outputs. It is used in the Aristocrat as the audio interface between the CPU, the guitar and the amplifier. This is a good place to find and discuss code for synthesis and effects which is specific to the Audio Codec Shield and Maple/Arduinos. MusicDsp.org Archive of Audio Effects (C/C++) Many years ago, when desktop computers first became powerful enough to process audio in real-time, a group of strangers online began sharing code with each other to synthesize musical instruments and effect audio with things like reverb, distortion and filters. Their collaboration was instigated to a large extent by Douglas Repetto. This link points to an archive of code examples which they shared with one another, and which became the direct ancestors of many VST plug-ins and virtual instruments in the early 2000s.
DAFX Conference The Digital Audio Effects (DAFX) conference is an annual academic event where papers on audio effects research is shared. Many of their publications are available for free online in pdf format. These papers contain valuable equations used to transform sound through DSP (Digital Signal Processing). It reflects much of the work done in the Music DSP archive above and which continues today.
The Scientist and Engineer's Guide to Digital Signal Processing A free and legal textbook in PDF format with hundreds of amazing code examples. Most of them are in BASIC so you can easily understand how they work. This is a good book for those who learn by example. It has many patient explanations of fundamental DSP concepts like imaginary numbers, filters, the Fourier Transform, convolution, etc.
Analog Devices Paper on Essential DSP effects Although its code examples are specific to the floating-point SHARC processor from Analog Devices, this paper teaches the fundamentals of DSP for many commonly-used audio effects. Note that relative to these examples, developing effects on the Aristocrat is easier because of the C/C++ programming capability which is provided by the Maple IDE.
Spinsemi.com Algorithm Development Although these code examples are specific to the fixed-point FV-1 DSP chip, the forum contains many good explanations of how to write audio processing algorithms.