I really do understand how the very strong way that some instructors chant the Adi Mantra could be jarring. Especially if you're used to hearing it chanted more gently.
There is a mantra called "Long Ek Ong Kar" with these words:
Ek ong kar sat nam siri wahe guru
This has to be chanted in a specific manner, with VERY strong emphasis on certain words in the mantra. First time I heard it, I thought, yikes! But I got used to it.
We chanted it for 2.5 hours a couple of times during teacher training--no music, just our voices. One time (and this is really cool) the sound vibrations from our voices alone made the gong go off, as if it had been very lightly struck by a mallet. No one was seated anywhere near the gong, including the teachers, so no one had touched it. It was amazing and was a real example that sound vibrations are a thing. It's one of my nicest memories from the training class.