Gong ageng

[1] Unlike the more famous Chinese or Turkish tam-tams, Indonesian gongs have fixed, focused pitch, and are dissimilar to the familiar puke crash cymbal sound.

It is circular, with a conical, tapering base of diameter smaller than gong face, with a protruding polished boss where it is struck by a padded mallet.

[3] Gong ageng are often proffered ritual offerings of flowers, food, and/or and incense before performances[4] or each Thursday evening[1] to appease spirits believed to live in and around it.

[2] The cost of expertly pure cast & beaten bronze has seen a rise in bronze-plated and bronze-laminated iron gongs created for the undiscerning expatriate.

[5] It is the single most costly and lengthy item to fabricate- and often requires multiple re-castings due to stress-cracks created in the beating process of forming it and undesired tonal or timbre qualities.

Actual pitch will vary, but a fine gong ageng of example of the Nusantara Museum of Delft was measured to have a fundamental tone of 44.5 Hz.

[8] The Gong Ageng has about a dozen prominent exponentially decaying partials, with some component frequency ratios that closely correspond to harmonics and others that are enharmonic.

A gongan is the time span between the gong ageng strikes, which are subordinate to the tempo: irama, and length of the structure (bentuk).

Two famous ones include the Surabaya Naval Dockyard statue (weighing over 2000 kg) and in the seaside resort of Ancol in Jakarta (approximate diameter 3 meters, weight several thousand kilogram).