It was a hobbyist, and it was a System Sensor speaker strobe. I may have been wrong about there actually being a voice evacuation message with music, as I haven’t found any such message on Wheelock or Fire-Lite’s website.
Back to the “use bells for new installations” suggestion, I think they would be okay to install for new installations as long as they are installed in a large open place, like a gym. I remember in elementary school, the phone would be tied to an external bell so the coaches in the gym could know when the phone was ringing. It used to be a speaker, but sometime between my fourth or fifth grade year, I think, they installed an 8-inch bell. I have no idea if it was AC or DC, but it sure got my attention when it rang, even with the cacophonous sounds of screaming children. (By the way, the bell pulsed a .25 second on, .25 second off, .25 second on, 1 second off pattern until the phone was answered or it went to the answering machine).