Available for download, Modartt Xylo from Pianoteq is an add-on for Pianoteq virtual instrument software. This add-on offers two specific instruments: the Xylophone and the Bass Marimba.
Both the xylophone and bass marimba are similar to the more commonly known vibraphone, but they utilize wooden bars instead of aluminum bars. Each bar vibrates when it's hit with a mallet, and each bar is paired with a metallic resonator, which has been tuned to amplify the sound of the vibration. The bass marimba offers notes two octaves below the xylophone.
Pianoteq's emulated versions of these instruments are modeled on a modern 3.5-octave French brand of xylophone, and a modern 5-octave French brand of bass marimba. Features inside of the software allow you to tune the response and performance of the instruments to your specifications. This software requires Pianoteq 3.6.4 or later to operate.