note bedham Braggins trichord Melakarta swaram karimba laras ajnas Shadja Mohanam POOR pentatonic hexatonic seleh pentachord meend octatonic ison ragams coccid rishabha promissory swara duplet diatonic nere Achala heptatonic hexachord solmization semitonal sargam slendro Sternorrhyncha flatted