The "Dual Defect Processor" Model 289 is a Buchla-format modular synth module that is based on the FV-1 from Spin Semiconductor. This repository contains several sets of alternate DSP programs for this module, with a focus on time-domain effects.
To use these programs, you will need some method of flashing the compiled builds on to a suitable EPROM. Alternately, if you have the FV-1 development kit then you may compile them from source and use the official development board to program the EPROM.
Unlike many commercially available program sets, these algorithms are made available under the MIT License and are free for commercial or personal use.
The reverb algorithms presented here are common in academic literature, but novel in terms of what is available in the public domain today for the FV-1. I welcome any discussion around the utility of these algorithms and further feedback on tuning and refining them.
The 289 is composed of two identical sections. The upper and lower sections can load distinct sets of 8 programs. The Cambridge programs are intended to be loaded into the top section, and the Boston programs into the lower. There are a number of use cases where the programs can interoperate.
The Waltham programs are an alternative bank for users who might prefer the thicker character of traditional, vintage programs.
The Cambridge programs are a diverse set of delay and stereo-widening effects. They are based on multi-tap delay lines which are scaled or modulated differently in each program to achieve different effects.
| D | # | Program | Description |
|---|---|---|---|
| 1 | 7 | New Delay | Mono 1s delay. Summed mono input. Separate left and right taps. |
| 2 | 3 | Long Chorus | Mono 1s delay. Summed mono input. Chorus on both taps. |
| 3 | 5 | Stereo Delay | Stereo 500ms delay. |
| 4 | 1 | Dimension | Stereo multi-chorus. |
| 5 | 6 | Reflections (Small) | Stereo early reflections, small space. |
| 6 | 2 | Reflections (Medium) | Stereo early reflections, medium space. |
| 7 | 4 | Reflections (Large) | Stereo early reflections, large space. |
| 8 | 0 | Width | Stereo reverb with size and width controls. |
The Boston programs are reverbs that are based on an 8x8 Feedback Delay Network (FDN). The programs are named for the aspect of the algorithm that can be modulated in each.
| D | # | Program | Description |
|---|---|---|---|
| 1 | 7 | New Delay | Mono 1s delay. Summed mono input. Separate left and right taps. |
| 2 | 3 | Darkness (medium) | Stereo reverb with variable input low pass filters. |
| 3 | 5 | Darkness (large) | Stereo reverb with variable input low pass filters. |
| 4 | 1 | Distance (large) | Stereo reverb with variable distance from source. |
| 5 | 6 | Chorus (medium) | Stereo reverb with variable chorus modulation. |
| 6 | 2 | Time (medium) | Stereo reverb with variable delay size/time. |
| 7 | 4 | Time (large) | Stereo reverb with variable delay size/time. |
| 8 | 0 | Width | Stereo reverb with size and width controls. |
The two sets of programs are designed to interoperate in useful ways when patched together. Here are a few ideas:
-
The Long Delay is the first program in both sets. Alone it is a 1 second, two tap delay. Patched together it is a 2 second 4 tap delay, or a really long pre-delay for a reverb. Remember you can always insert additional analog processors like filters between them or in feedback paths.
-
Try Reflections on top, blended with the dry, and then patched to a reverb below, also blended again. A large number of flexible, naturalistic reverbs are possible this way.
-
The Width reverb is the last program in both sets. It might be useful for those that need two identical reverbs for quadraphonic output.
The Waltham programs are a simplified interpretation of the concert hall program from one of the well known early digital reverbs. The parameters for reverb time and equalization are greatly simplified to accommodate the small number of controls.
| D | # | Program | Description |
|---|---|---|---|
| 1 | 7 | Long Delay | Mono 1s delay. Summed mono input. Separate left and right taps. |
| 2 | 3 | Stereo Delay | Stereo 500ms delay. |
| 3 | 5 | Sparse (medium) | Stereo hall with sparse taps, low diffusion. |
| 4 | 1 | Sparse (large) | Stereo hall with sparse taps, low diffusion. |
| 5 | 6 | Diffuse (medium) | Stereo hall reverb, high diffusion. |
| 6 | 2 | Diffuse (large) | Stereo hall reverb, high diffusion. |
| 7 | 4 | Far (medium) | Stereo hall reverb, high diffusion, distant source. |
| 8 | 0 | Far (large) | Stereo hall reverb, high diffusion, distant source. |
Note that the 289 program selection is not the same ordering as the EPROM
- The
#column indicates the program position on the EPROM. - The
Dcolumn indicates the algorithm position on the 289 panel.