Yamaha Quality and Design Kruspe style wrap A horn with a Kruspe style wrap has the 4th valve on the near end of the other valve. The Kruspe wrap is the basis of modern large bell horns.Hand-lapped rotary valves and slides Rotary valves and slides that have been hand-lapped are airtight and have smooth action.Articulated key levers Articulated key levers have responsive motion.Hammered and annealed bell Hammering and annealing are processes so important to the instrument's acoustic characteristics that Yamaha employs computer-controlled equipment to ensure consistently superior sound. Hammering enables bells to have a rich, resonant tone that blends beautifully with other instruments. Annealing is a cooling and heating process that makes it easier to control the acoustics of the instrument.Cyclical bore A cyclical bore is a perfectly cylindrical tubing assembly in combination with a conical mouthpipe and bell system. This allows for consistent air flow throughout the horn.Tapered valves Tapered valves wear for a long time without air leakage.Excellent sound in all registers The combination of the secure high register, strong projection, and quick attack of the Bb horn with the rich, warm timbre of the F horn make the double horn ideal for most playing situations.