Hihat Openness Control Feature - Design Document

This document does not describe a feature in DrumGizmo, but is rather a collection of ideas for how a future feature could be implemented.

Midi drumkits can sometimes send midi events when the hihat pedal position changes.

No standard way exists for how this is done, but two major ways have been observed: 1) When the hihat is hit, different note-on events are sent depending on openness, and a specific note for when the hihat is completely closed. 2) When the hihat is hit, the same note-on event is sent, but when the openness changes a midi CC event is sent with the openness parameter.

Somehow map these events to control DrumGizmo sample engine in the most natural way possible.

Since no one way exists, the feature should be configurable by the users to make it work with whatever kit they have available.

It should be possible to also use this feature with a DAW, without a drumkit, using “mouse-notation” in the editor.

Extend the features of the sample generation to include openness parameter, similar to the position parameter of the snaredrum. When a hihat note is played, select the appropriate one from the set.

The openness must be mappable though the midimap file, which needs extending with a new syntax for mapping either notes to “openness” or specify how CC events are mapped to openness.

If a hihat note is being played and the openness changes the following should happen: 1) The percentage of the current play position is calculated (eg. 40% in) 2) A new sample is selected from the new “openness group” 3) A fade-out is activated in the current sample. 4) The new sample starts playing also 40% into its duration, with a similar fade-in resulting in a cross-fade between the two.