suggestion: when playing a range, render the range twice and play the "second repeat".

[esaruoho]

If playing the contents of a specific pattern, soundbox renders the pattern first before playing. if you are playing a range, a pattern with longer delay effects will always start from "0 volume", and "0 delay" when playback loops.
if the range is rendered twice, and only the "second repeat" is played, this will increase the loopability of pattern playback (i.e., the second repeat of the pattern will have the audio "tail" of the first playback of the pattern).