What if each drum in your drum set was engineered as an instrument unto itself? Each tom designed to respond perfectly within the confines of its respective frequency without compromise over any other area of your kit. This is the mission behind Reference Series. A complete set of individually engineered, incredible sounding drums.In 1999, Pearl began its most ambitious undertaking, The Masterworks Series, the world's first truly custom drums. Designed for the player by the player. Every aspect of the manufacturing process was custom made, from the number of wood plies, the wood selection, to the final finish. Over the last five years, through arduous listening tests, Masterworks has taught us a great deal about drums and what makes the perfect shell. So forget what you think you know about drums and take a close look at Reference Series, the most acoustically advanced drums in the world. To fully understand the Reference Series you must understand that the desired tonal characteristics of a 10" tom are completely different than that of a 22" bass drum. Thus to use the same material in both drums would result in a compromise.Reference Series drums use a combination of task-specific bearing edges and three time-proven woods: birch, maple, and African mahogany. Using maple as a sole material has long been the traditional choice for shells and for good reason. Maple provides smooth, well-balanced tone that is perfect for a 12" tom. Pearl's 18" and 20" bass drums use four inner plies of mahogany with two outer plies of maple. As the sizes of the bass drums increase, so do the amounts of mahogany. Pearl's 22" and 24" bass drums incorporate an amazing six inner plies of mahogany surrounded by two outer plies of maple for the ultimate in solid responsive bass frequencies.With Reference Series, it's not about compromise, it's about every drum in your kit performing at its optimal capacity.