Like other Balinese gamelan, gender wayang are only approximately standardized in relative pitch, though instruments of each group are precisely tuned with masterful pitch pairing and register stretching. Absolute pitch varies according to the bronzesmith's preference. As a result, individual instruments are rarely exchangeable with those from any group other than its original. One instrument in the each pitch register, pengisup (sucker), are tuned a hair higher than their mates, pengumbang (waver); due to our logarithmically scaled sense of hearing, the lowest notes need to be paired further apart in absolute pitches than the highest to achieve the same, ideal rate of “shimmer” at unison. Further, octave intervals are stretched to be slightly more than double the hertz to achieve a similar “shimmer” at octaves.
