A gritty analog style echo effect for your KORG logue-sdk compatible synthesizers! (C) hammondeggs 2019

Video Demo

This requires the 2.0 software installed on your synthesizer!

As always, these are to be used at your own risk!

A quick word...

I've been having a ton of fun creating these plugins. If you like stuff like this and my other work, by all means feel free to contribute whatever you can to help support this!

Ensure your synthesizer is capable of installing plugins using the 1.1 API (that is, they are running OS 2.0 or greater). Also ensure you have installed the latest KORG minilogue/prologue sound librarian. Now, before you do anything else, perform a full and complete backup of your synthesizer and save this to disk before continuing. See the sound librarian manual for instructions on how to do this if required. Next, select the USER DELAY FX tab on the librarian, and drag and drop the requisite file to an available slot in the librarian :

  • for minilogue xd users, please use grit.mnlgxdunit
  • for prologue users, please use grit.prlgunit.


Three parameters are available:

Time : Adjusts the delay rate. This may seem 'backwards' compared to the factory delays, but will be explained shortly.

Depth : Adjust the feedback. Careful! Setting this to a value > around 66% will cause the delay to feed back positively on itself. It can get loud. However, to help with this, there is a compressor/ALC on the feedback signal, as well as a saturator - so don't be surprised if your over-fed back delay starts to get crunchy!

Shift-Depth : Adjusts the wet/dry mix. Note, to help with the possibility of the over-fed back delay getting a bit loud, this is skewed slightly to the 'right' - that is, to get a full 50/50 wet/dry signal, you will have to set the knob to 75%. Thus, the default "full mix" is actually more dry than wet. You can still adjust the wet/dry values from full dry through to full wet, just more emphasis is placed on adjusting the wet level with the dry signal present.

A few notes about the implementation...

Moving rate vs moving read position : Lets consider analog tape delays for example. These can be implemented using both a "moving read head" approach and a "variable tape speed" approach.

With the moving read head approach, the tape speed is constant, and you simply move the write head 'further away' from the read head to increase your delay time. While you're moving this head, you will be 'stretching' (or squishing) the signal, thus you will perceive a change in pitch. Once you stop moving the head, the delay time is set, and you are back to recording at the input rate.

With the adjustable rate approach - the approach used in this delay, the read/write heads are fixed in place, and you change the speed of the tape moving between them to change the delay rate. This tends to preserve variable rate changes, but is much more difficult to implement in software within the CPU time limits.

In addition, a small jitter is added to this rate to simulate the slight hardware inaccuracies with a 'real' tape delay - plus some filtering is applied as well both high pass and low pass.

The "Variable Rate" approach also approximates the means used by a bucket brigade delay - the total delay 'distance' is fixed, but you can set how quickly the audio signal moves through the IC via the clock rate.


Download the zip here (contains both minilogue and prologue formats)