Welcome to the nexus friend
Can't say I know enough about harmalas other than I use it in my changa and have only recently started taking 150mg of free base to prepare for a pharma trip here soon. At that low of a dose there was hardly any effect but I was mainly just testing the nausea factor.
The changa I just here a high pitch ringing, and bleep bloop sounds. I'm pretty sure that's the dmt though, plus I'm usually in total silence.
Maybe someone else will chime in that has maybe had something similar happen and an explanation.
Enjoy the community, safe and happy journeys
Peace