In a final attempt to understand the quite controversial global groove function of Renoise, I aimed to recreate different global groove percentages using only the delay column. After trying out different things and consulting the documentation several times, I came to the conclusion that several things are not right.
The documentation says that when having a LBP setting of 4, where each line represents a 16th note, then the groove (when all sliders are set to the same values) will shift line 1 and 3 forward in time (they will be triggered later) while leaving lines 0 and 2 untouched. If we ignore for a moment that the sentence “Note that the numbers 0&1, 1&2, 2&3, 3&4 only apply to line numbers when using a Lines Per Beat Setting of 4” is incorrect and should rather read “Note that the sliders 0&1, 1&2, 2&3, 3&4 affect a delay of lines 1, 3, 5 and 7, respectively, when using a Lines Per Beat Setting of 4”, then everything is working as expected so far.
To figure out the correct delay to use in the delay column I did the following: I created a pattern where a hihat is played on each row. I activated the global groove. I then rendered the first two rows (0 and 1). I hence expect the second row to be delayed according to the global groove settings. Looking at the rendered part in the sample editor, I now deleted the first half of the sample (from length 0 to length 80) in order to only see what happens to the delayed line.
I first did this procedure with the global groove set to 100%. According to the documentation “Technically speaking, a 100% groove would mean that the second note is triggered together with the third”. Hence, in the sample editor, I should see complete silence now since I only rendered up to, but not including the third note. However, here is what I get:
The sample is delayed by an amount of something between AA and AB (where ff would actually be 100% as described in the documentation).
Next, I tried with a global groove setting of 50%, which is arguably more musically useful. Here is what I get:
The sample is delayed by an amount of something between 55 and 56. While this is clearly 50% of my first measure, it should be 80 according to the documentation.
The numbers 55 and AA should look familiar to us. They represent exact triplets with a LBP of 4. However, the global groove does not accurately hit these exact triplets.
[b]To sum up, we learned 3 things:
The global groove, while apparently trying to operate on triples, is not accurate