For sound and loudness comparison, here are videos of Grey Larsen demonstration the Session D whistle and the High Whistle in D.
From the Carbony website: The thin wall process of the Carbony tapered whistle design gives warm response of the lower octave. When playing with other instruments these notes are rarely heard, but not with Carbony™ composite! Our material resonance enhances lower frequencies and mutes upper register shrillness producing a volume balance in all registers.
All whistles now have our revision four fipple design. Our patented two-piece design enables machining accuracy of 0.001″. Our two-piece assembly also facilitates optimal material selection. The blade/body is machined from aluminum and anodized for hardness, creating a stiff precise blade for maximum oscillation. The tip/windway is machined from marbled ebonite, the same material used to make saxophone and clarinet mouthpieces. Safe to put in mouth and durable enough to honor our lifetime warranty. The interface of the whistle is precision ground to mate with the fipple and form a tuning slide required in all professional grade whistles.
The Carbony™ tapered design is based on the Copeland tradition and we were fortunate to have Michael Copeland play an early design and offer both encouragement and his perspective of whistle making.
Carbony™ instruments are:
• Virtually indestructible – material will not crack, break or rot
• Geometrically stable – over all temperatures and humidities
• Stays as built – no warping or drying out over time