A gong is an East Asian musical instrument that takes the form of a flat metal disc which is hit with a mallet.

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.

Types of gong

Suspended gongs are played with beaters and are of two main types: flat faced discs either with or without a turned edge, and gongs with a raised center boss. In general, the larger the gong, the larger and softer the beater. In Western symphonic music the flat faced gongs are generally referred to as tam-tams to distinguish them from their bossed counterparts, although the term "gong" is correct to use for either type. The gong has been an ancient Chinese custom for many eras. They are used to start the beginning of sumo wrestling contests. They were first used to signal peasant workers in from the fields as some gongs are loud enough to hear from up to 50 miles away.

Large flat gongs may be 'primed' by lightly hitting them before the main stroke, greatly enhancing the sound and causing the instrument to "speak" sooner, with a shorter delay for the sound to "bloom". Keeping this priming stroke inaudible calls for a great deal of skill. The smallest suspended gongs are played with bamboo sticks, or even western-style drumsticks. Contemporary & avant-garde music, where different sounds are sought, will often use friction mallets (producing squeals & harmonics), bass bows (producing long tones and high overtones), and various striking implements (wood/plastic/metal) to produce the desired tones.

Chau gongs

The chau gong is made of copper-based alloy, bronze or brass. It is almost flat except for the rim, which is turned up to make a shallow cylinder. On a 10" gong, for example, the rim extends about a half an inch perpendicular to the gong surface. The main surface is slightly concave when viewed from the direction to which the rim is turned. The centre spot and the rim of a chau gong are left coated on both sides with the black copper oxide that forms during the manufacture of the gong, the rest of the gong is polished to remove this coating. Chau gongs range in size from 7" to 80" in diameter.