REV2 Degrader™ Documentation


Thank you for purchasing REV2 Degrader™ (R2DG for short) for Mac OS 10.11.x or higher! R2DG is a generative sound design tool for the Sequential Prophet REV2 polyphonic analog synthesizer. The application is designed to algorithmically morph parameters on the instrument in realtime. Keep playing or record the results as up to one-hundred-twenty-one parameters on the REV2 are changing all at once! Use R2DG to create anything from chaotic, rapidly-changing textures to slow, evolving drones. R2DG breathes new life into the Prophet REV2 allowing you to explore endless, unique soundscapes illustrating how powerful and diverse the Prophet REV2 really is. This tool is designed to help you uncover new territory hidden within the sonic depths of your instrument. Although R2DG was specifically built to work with the Sequential Prophet REV2, the software is independently designed and developed by John C.S. Keston of and unaffiliated with

Unzip the REV2 Degrader zip file. Start by reading R2DG_readme.txt and the End User License Agreement or EULA (REV2_Degrader_EULA.txt). Next, double click on “REV2 Degrader.dmg”. Drag the REV2 Degrader file into the Applications folder. Once it is copied to Applications you may eject the REV2 Degrader volume from your desktop by dragging it to the trash.

To register and start using R2DG it must be copied into your Applications folder and your computer must be connected to the internet. Once you’re connected open R2DG and choose “Register REV2 Degrader” from the “File” menu. Fill out the form including the registration key that was emailed to you after purchasing the software and press SUBMIT. Upon successful registration the upper left of the R2DG interface will read, “Registered to <first name> <last name>”.

Please proceed with caution! Degrading, morphing, and randomizing parameters on your synth may cause extremely loud sounds. Keep your levels low and be prepared to quickly pull down the volume.


R2DG works by scaling or randomizing customized groups of parameters on Layer A of the Sequential Prophet REV2.

1. Start by connecting your Prophet REV2 to your computer with a USB cable.

2. Next open REV2 Degrader, click on the menu underneath the “Connect REV2” label, and choose the “Rev2” option.

3. USB is recommended, but if you need to use MIDI DIN connections choose the name of your MIDI interface from the “Connect REV2” menu.

4. If the option “Rev2” is not available check your connections and then press the blue button to the right of “Connect REV2”.

5. Afterward “Rev2” should be a choice in the menu. Do not press the blue button to the right of the “Connect REV2” label after choosing “Rev2” from the menu. The button is there to refresh the list of MIDI devices and will disconnect the REV2.

6. Once you have selected “Rev2” from the “Connect REV2” menu and registered your software you can begin.

7. The options titled “AU DLS Synth 1”, “from REV2 Degrader 1”, and “from REV2 Degrader 2” will not work with R2DG.

The most simple thing R2DG will do is randomize the parameters on Layer A. Isolate Layer A by making sure that Split A|B and Stack A+B are both off. Next, choose the parameters you’d like included and then press [play/pause] or the spacebar. If [loop] is pressed the checked parameters will be randomized continually at the rate specified under “RATE (ms)” until [interrupt] or the spacebar is pressed again. The rate ranges from 1 millisecond to 3000 milliseconds (3 seconds) per parameter change. This technique will jump from one value to the next creating unpredictable or chaotic results.

Press the [interpolate] button to smoothly scale parameters from one to the next at the specified rate. Use this technique to morph values smoothly. This is where the magic happens. Imagine up to one-hundred-twenty-one hands turning knobs on your REV2 all at once! However, the best approach is to be selective about the parameters you choose for the morphing process. Try all sorts of combinations to suit your personal sound design aesthetic. The twelve presets included offer a few examples of how it will sound to start degrading from different values and with different groups of parameters selected. Use the [Update Preset] button to store your own sets of values and parameter choices. Presets cannot be selected while degrade is operating.


The latest version of R2DG includes a mophing step editor for the gated sequencer. Use the tabs in the bottom right to switch between [MOD/LFOs], [GATED1], [GATED2], [GATED3], and [GATED4]. Edit the steps with the steps grid or the numbers below. The steps grid cannot be changed while the degrading transport is playing, but you can still edit the steps with the number boxes. You can also randomize the steps for each of the four tracks independently using the RANDOMIZE button above each steps grid.


R2GD opens with twelve presets adapted from the AudioCookbook REV2 Experimental Patch Bank. Each preset stores the state of the checkboxes, the values of every parameter displayed, the degrade RATE (ms), the state of the [interpolate] and [loop] buttons, and the state of the section toggles (i.e. [All OSC OFF]). Pressing a preset button labelled 1-12 will send the parameter values to Layer A on your REV2 and recall the state of the R2DG interface. This makes it convenient to use R2DG in a performance setting. Keyboard shortcuts for the presets are mapped to 1,2,3,4,5,6,7,8,9,0,-,=.

The twelve presets included offer provide examples of how it will sound to start degrading from different sets of values and with different groups of parameters selected. Use the [Update Preset] button to store your own sets of values and parameter choices. Presets cannot be selected while [degrade] is operating. Once you have some presets setup the way you want them choose “Save New Presets File” from the “File” menu. You will be prompted for a filename and location. Your presets will be stored with a .json extension. To load a previously stored file choose “Load Presets File” from the “File” menu. You may save as many preset files as you wish, each with twelve new starting points to morph from. You may also choose “Restore Default Presets” from the “File” menu. This will replace all of the presets in memory, so make sure that you have saved any customized presets first.

Two more preset bank files are included with the R2DG package. “R2DG_Presets_Inits.json” includes twelve initialized presets without any checked parameters. This way to can design your own presets from a default starting point. Within “R2DG_Presets_Inits.json” you will find 1-6 are initialized presets and 7-12 are initialized pad presets. “R2DG_Presets_Bank_2.json” includes twelve more unreleased presets with groups of parameters pre-selected for optimal morphing.

You may want to use an existing patch on your REV2 as a starting point for the degrading process. The patch can then be stored as a REV2 Degrader preset to recall at anytime. Keep in mind that the REV2 Degrader presets do not include all REV2 parameters. Currently, the sequencer and gated sequencer as well as a few other parameters are not included. Also, the patch retrieval will only work if your REV2 is updated to firmware version OS To update your firmware please follow the instructions at Once you’re up to date, follow these steps to get a patch from the REV2:

1. Make sure your REV2 is connected to REV2 Degrader
2. Press the “GET FROM REV2” button in the REV2 Degrader interface
3. On the REV2 go into “Globals” and select “32. Dump Prog” then press “Write”
4. IMPORTANT: Exit the Globals menu on the REV2 before pressing “DONE”
5. After exiting “Globals” on the REV2 press “DONE” in REV2 Degrader
6. Transport and “interpolate” are temporarily disabled during this process
7. To store the patch in REV2 Degrader press “Update Preset”

Q: Why after verifying is there a box that says, “REV2 Degrader is damaged and can’t be opened”?
A: This is what is called a Gatekeeper error and happens on Macs that do not have the Preference set to allow applications to be installed from the internet. This article explains how to resolve the issue: How to fix damaged app message. If you get the error with macOS Catalina follow these steps.

Q: Is there a way to fine tune the values in the number boxes?
A: Numberboxes can be changed by clicking and dragging on the box, entering numbers by hand, or using the arrow keys. Clicking and dragging is the least accurate method. Use the up/down or left/right arrow key to nudge values at the smallest increment, or click on the box and type in a specific value.

Q: Is it possible to degrade Layer A and B on my REV2?
A: Currently R2DG only operates with Layer A on the REV2. If you’d like to copy a morphed patch to Layer B and then continue degrading Layer A follow these steps from the REV2 manual: 1. Press both the split a|b button and the stack a+b button simultaneously. Turn the parameter knob and select copy layer a to b. 3. Press the write button. Layer A is copied to Layer B.

Q: When I try to get a patch from my REV2 is says, “No data received from REV2. Please try again”?
A: Make sure that your REV2 is configured in Globals to send SysEx data from the correct cable. Press Globals then choose parameter “11. MIDI Sysex Cable” and choose MIDI or USB depending on how you’re connected.

Q: Why did REV2 Degrader stop sending MIDI values to my REV2?
A: This shouldn’t happen, but might if you have all the parameters checked and “RATE (ms)” at 1 millisecond. This causes a lot of data to be sent to the REV2 and can potentially cause an error in the REV2’s MIDI interface. Quitting REV2 Degrader and re-starting will get it working again.

Q: Can I install REV2 Degrader on more than one computer?
A: Currently the registration system allows for R2DG to be installed on one computer. If you need to install it on more than one computer please contact to make arrangements