Concert Xylophone YX-500F Acoustalon model. The new 500 Series is available in both Acoustalon and Rosewood and will replace the YX-335 Acoustalon and the YX-350A Rosewood xylophones. The 500 Series xylophones come with two-position resonator slots and features new bar sizes for consistent tone quality throughout the range of the instrument. Its gas shock height adjustment frame allows easy, effortless adjustment by the player. Offering a full, authentic wood sound with new size of bars, the new series features a foldable frame for transport and easy set up.