Gambang kromong is a traditional orchestra of Betawi people which is a blend of gamelan, Western music and Chinese-style pentatonic base tones.
[1] Nie Hoe Kong, Kapitein der Chinezen, a musician and Dutch-appointed leader of the Chinese community in mid-18th-century Batavia, is considered one of the early figures who developed the Gambang kromong.
One of the popular groups was Gambang Kromong Ngo Hong Lao, whose players were all ethnic Chinese people.
For the wealthy Chinese, it was a custom to liven up a party by calling a gambang kromong orchestra, usually accompanying a song.
[1] Gambang kromong used the Chinese scale instead of the local slendro typical in Javanese, Sundanese, or Balinese gamelan.