Sorry, that’s not possible with the looper.

Information about how the speed parameter works when tempo sync is turned on is outlined here: https://cdn.eventideaudio.com/manuals/h90/1.9.7/content/algorithms/looper.html

You may be able to program CC messages that trigger the Loop start trigger instead of using MIDI tempo sync. This way, your clock/sequencer will tell the H90 to start the loop at a given time, and you can find different play speeds that may sync up at different tempos.

We’ll consider this feature for an update.