Horn and photo courtesy Brent Lee. One of the bells could be reversed to provide good sound volume in both directions. The horn shown is an early version (1950's) with a two-piece #31 bell and bronze power chambers.
The S-2B was a less popular Leslie two-chime horn compared to the S-2M. It used the #31 and 37 bells, which are also the two lowest notes in the reasonably popular three-chime S-3K.
Factory tuning: 311 and 370 Hz (approximately D# and F#).
The S-2B was not a very common horn despite its pleasing minor 3rd interval.
It was presumably used by some railroads in lieu of the S-2M, but such uses have not been
S-2B sound sample (courtesy Brent Lee):Sample 1...692kB...32 seconds