Did the bells play a musical tune, perhaps with harmony, but it maintained an even level of volume, and perhaps it sounded a bit stilted? If so, you may have heard an automated carillon or chime.

A set of seven bells in Niles, Illinois played via automatic strikers.

Many carillons and chimes are programmed to play tunes via automatic strikers, as described in the clock-chime section. The tunes tend to be at a slower pace, with less harmonic and rhythmic nuance, and the bells are played at only one volume level–loud. Usually the melodies will play at the same time every day, perhaps on the hour, or just a few times per day. 

There are actually many historic and modern mechanisms to ring bells automatically, even if they are seldom used in North America. 

One historic method dating back to the sixteenth century is the programmable drum. Have you ever seen the rotating drum in a music box? In which the pins on the drum push up levers that strike tone bars? This mechanism–much larger here!–is used to program sets of bells, too. 

The programmable bell drum in Ghent, Belgium.

You’ll need to be near Hoover Tower on the campus of Stanford University, though, to hear the only operable programmable drum in North America.