The Reference Series sets the new boundaries to the drumming. The innovative design of the boiler unprecedented sonic dimension is realized. Unlike as is usual, various types of wood (Birch, Maple, Mahogany) combines different for each drum size and both the thickness and the bearing edge of the tank varies. Thus the character of each drum sound is converted to 100%, and the kit sounds perfect as a complete unit. To describe in words how good the new Reference series sounds, it is almost impossible and not intended to replace an individual listening experience when you play these instruments. In the Reference series for each individual drum size, the optimum boiler design has been established. This corresponds to the sound the sound you want each character (eg a 24 "bass drum, a 10" tom, or a 13 "snare) to 100% and sounds perfect. The boiler design is determined by the following parameters: Shell Thickness: 6-ply, 8-ply, 20-ply Species: Maple (M), Mahogany (MH), Birch (B) layers (plys): 2-ply (2), 4-ply (4), 6-ply (6) a statement from the outside in (see example) Bearing: 45 ° rounded (45R), 45 ° straight (45S), completely round (RD)