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Ranat thum
Classification Percussion (idiophone)
Related instruments
Roneat thung, ranat thum lek, ranat ek

The ranat thum (Thai: ระนาดทุ้ม, pronounced [ranâːt tʰúm]) is a low pitched xylophone used in the music of Thailand. It has 18 wooden keys, which are stretched over a boat-shaped trough resonator. Its shape looks like a ranat ek, but it is lower and wider. It is usually played in accompaniment of a ranat ek.

ranat thum bars are typically made from bamboo, although instruments with rosewood (Dalbergia oliveri; Thai: ไม้ชิงชัน; mai ching chan) bars can also be found.

It is similar to a Cambodian xylophone called roneat thung.