S. E. Shires:

Red Brass: 90% Copper, 10% Zinc. Warm, rich sound with complex overtones, allows for a wide range of colors at different dynamics.

Yellow Brass: 70% Copper, 30% Zinc. Clear, pure sound with strong fundamental, keeps a very consistent tone color and overtone structure throughout the range of dynamics.

Gold Brass: 85% Copper, 15% Zinc. Combines many of the characteristics of yellow and red brass for a very balanced and flexible sound.