Nipple gongs have a raised boss or nipple in the centre, often made of a different metal to the rest of the gong. They have a clear resonant tone with less shimmer than other gongs, and two distinct sounds depending on whether they are struck on the boss or next to it. They most often are tuned to various pitches.
Nipple gongs range in size from 6" to 14" or larger. Sets of smaller, tuned nipple gongs can be used to play a tune. A Bau gong is a type of nipple gong used in Chinese temples for worship.
Gongs are broadly of three types. Suspended gongs are more or less flat, circular discs of metal suspended vertically by means of a cord passed through holes near to the top rim. Bossed gongs have a raised center boss and are often suspended and played horizontally. Bowl gongs are bowl-shaped, and rest on cushions and belong more to bells than gongs. Gongs are made mainly from bronze or brass but there are many other alloys in use.
