Load a Sine instrument for easy testing. A couple come packed with Renoise. (Any sound would do really, a steady tone of some type makes it easier to measure.)
Enter in a track and play so you have a steady tone going through.
Check headroom in Song Setting. Set it to -6dB.
Click on Track DSPs, navigate to Master track, click on the reported peak level to reset it and note the value.
Change Track Headroom to 0dB.
Check reported peak level again. (For me this is the same as above, when set at -6dB. it should be 6dB higher.)
Change Track Headroom to -9dB.
Check peak level. (This correctly shows as 3dB lower than for headroom at -6dB.)
No headroom value between -6dB and 0dB appear to make any difference. I am positive they have in the past though!
Using a sample that is normalised to 0dB and has its instrument volume set to 0dB, playing on a track whose volume is to set to 0dB, with the master track set to 0dB, with no other volume adjustments, etc., etc… then I get a 1:1 relationship between the track headroom and the reported peak level in the master track.
If you’re testing with the Chip-Sine.xrni included with Renoise, please keep in mind that the sample/instrument isn’t actually normalised to 0dB, so this will definitely skew your results.
Yeah I knew about that dBlue, hence why only mentioning relative levels and not absolute ones.
Was an (different/even more) rookie mistake this time! At some point in my testing I had loaded a Maximiser into the track I was playing in and didn’t notice. Doh!!! Sorry for the wasted time.