As Jim said, I’m a classical pianist (majored in performance on violin and piano in college) and I have the Marvel M90-R. The only time I ever experienced feedback was once when I didn’t have them solidly pushed in so that all I can feel with my finger is the tip of the speaker thing. I have domes that have a thin wing that’s in two pieces and is definitely not any kind of closed dome. I’ve never experienced the tremolo effect that people talk about here on the forums.
My audiologist used the Phonak MyPhonak app and the “Remote Support” option to set up my “Piano Program”. I placed my phone on my piano music rack and she could see and hear me and I could see and hear her. Then I would play a passage and some scales and arpeggios and tell her what I thought the problems were. She would make adjustments and we would go through the same procedure over and over. With each iteration she would write the changes to my Marvels. Now whenever I sit down to the piano this is the program I change to. I only have two extra programs set on my Marvels, 1. Music, 2. Piano. If I’m going to the symphony or listening to live music I use the Music Program. Whenever I play the piano, I use the Piano Program.
I have a 7’ 5" Kawai Concert Grand piano in a 35 x 20 room with ceramic tile floors and a 2 1/2 story tall ceiling. It’s a wonderful place to have a large grand piano. However the volume when playing fortissimo is very loud. My Piano program cuts the volume down by several steps and everything works out very well. I’m very pleased with how my Marvels are working with music.
The most pleasant surprise with my Marvels is the amazing high quality of streaming music. I’m a bit of an audiophile and have spent a good bit on high quality audio equipment. My Marvels rival my best headphones. I have a lossless CD quality subscription to Primephonic and with my Marvels I can readily hear the quality difference between MP3 on my Google Play Music subscription and lossless CD quality on my Primephonic subscription.