I recall the pianos. Some talented brothers would sometimes play the harp along with piano in one cong. my wife and I attended. A few years ago a younger brother asked if he could bring an electronic keyboard for one of the meetings and that he could play the sheet music to the Sing Praises songbook, but his kind offer was refused. He was a very talented pianist and organist - it seemed he could play anything by ear. He was later discouraged by other elders who said he was wasting his time with the piano. Eventually he gave it up altogether.
Photo from a postcard of Brooklyn Bethel, showing piano at 400 seat auditorium. (Photo from ebay)