Gamelan metallophones have inharmonic spectra, and their scales (pelog and slendro) are related to those spectra

The bronze instruments of the Javanese and Balinese gamelan — saron, gender, bonang, kenong — vibrate in inharmonic modes because of their two-dimensional shapes (bars, kettles). Their spectra have prominent partials at non-integer-multiple ratios. For example, saron bars have a characteristic spectrum with partials approximating certain ratios that do not match any harmonic series. Sethares shows that the pelog (7-note) and slendro (5-note) scales of the gamelan correspond to minima in the dissonance curves of these inharmonic spectra — the scales are ‘related’ to the timbres. This explains why gamelan music sounds consonant despite using intervals that seem ‘out of tune’ from a Western perspective: those intervals are consonant for those timbres. It also explains why mixing gamelan and Western instruments is difficult: their timbres require incompatible scales.

Examples

A saron bar’s partial structure produces a dissonance curve with minima near pelog scale intervals. Playing Western 12-tet intervals on a saron sounds dissonant because 12-tet does not align with the saron’s spectral structure. The gamelan and voice are compatible because the voice’s harmonic spectrum also has consonant intervals near pelog steps.

Assessment

Explain why playing a Western major triad on a gamelan saron sounds dissonant. Why would re-tuning the gamelan to 12-tet not solve this problem? What would need to change about either the instruments or the scale for Western and gamelan sounds to be played together consonantly?