We study classes of musical scales obtained from shift spaces from symbolic dynamics through the "distinguished symbol rule", which yields scales in any n-TET tuning system. The modes are thought as elements of orbit equivalence classes of cyclic shift actions on languages, and we study their orbitals and transversals. We present explicit formulations of the generating functions that allow us to deduce the orbital and transversal dimensions of classes of musical scales generated by vertex shifts, for all n, in particular for the 12-TET tuning system. For this, we use first return loop systems obtained from quotients of zeta functions, and integer compositions as the combinatorial class representing all musical scales. We develop the following case studies: three zero entropy symbolic systems arising from substitutions, namely the Thue-Morse, the Fibonacci, and the Fagenbaum scales, the golden mean scales, and a shift of finite type that is not a vertex shift.