homotetrachordal (was Re: The 'Arabic' temperament

> Subject: Re: The 'Arabic' temperament
>
> --- In tuning-math@y..., "genewardsmith" <genewardsmith@j...> wrote:
>
> > The 7-tone MOS is Mohajira:
> >
> > [5, 4, 5, 4, 5, 4, 4]
> > [9, 7, 9, 7, 9, 7, 7]
>
> And the alteration with 5, rather than 3, homotetrachordal octave
> species is the Arabic Diatonic: 5, 4, 4, 5, 5, 4, 4.
>
> Whenever you find an MOS, you should always check if some alteration
> of the MOS gives more homotetrachordal octave species.

Definition needed for homotetrachordal please! Feel free to point out
differences with omnitetrachordal and any other prefix-tetrachordal you
know of!

thanks a lot

Bob Valentine

--- In tuning-math@y..., Robert C Valentine <BVAL@I...> wrote:

> Definition needed for homotetrachordal please!

Homotetrachordal: (of an octave species) Having two identical ~4/3
spans, separated by either a ~4/3 or a ~3/2.

Example:

the octave species

C Db E F G Ab B C

is homotetrachordal, since the interval pattern from C to F is
identical to that from G to C.

> Feel free to point out
> differences with omnitetrachordal

Omnitetrachordal: (of a scale) All octave species are
homotetrachordal.