Confusing syntax in two sentences

Question

I seem to be confused by the constructions of these two sentences from a Medieval Latin text:

1. Unde vocum alia suavis est illa, scilicet quae subtilis, spissa, clara et acuta est.

and

2. Multiplicem superparticularem et multiplicem superpartientem sunt nullas tenere consonantias, quia ad simplicem descendunt et in compositioni transeunt.

In (1), I wonder how alia is working together with illa, and in particular how that first clause is as a unit functioning with unde. Something like From where ... namely that which is subtle, compact (?), clear and sharp.

In (2), I find the abundance of accusative confusing in conjuction with "sunt". I find it unclear whether tenere ought to be an infinitive or if it is the adverb "tenderly". Maybe someone might have an idea?

The source is the Summa de speculatione musice by Walter Odington (born c. 1260) about music theory.

The full passage including both phrases:

Unde vocum alia suavis est illa, scilicet quae subtilis, spissa, clara et acuta est. Alia perspicuaque omnem implet continuum locum, sicut clangor tubarum. Alia subtilis, cui non est spiritus multus sicut infantium, mulierum, aegrotantium. Alia pinguis, scilicet cum spiritu multo, ut virorum. Alia acuta, id est tenuis, ut in chordis. Alia dura, quae violenter emittit sonos, sicut tonitruum. Alia aspera, scilicet rauca, quae dispergitur per inimicos et dissimiles pulsus. Alia caeca, quae statim ut emissa est conticescit. Alia vinnola, quae est mollis et flexibilis. Alia perfecta, alta, scilicet et clara et suavis, et in illa etiam dissonum delectat. In aspera vero et consonum auditum offendit. Multiplicem superparticularem et multiplicem superpartientem sunt nullas tenere consonantias, quia ad simplicem descendunt et in compositioni transeunt.

Answer 1

Regarding sentence (1), I believe to understand the function of alia, you have to look at the following sentences:

Unde vocum alia suavis est illa, scilicet quae subtilis, spissa, clara et acuta est. Alia perspicuaque omnem implet continuum locum, sicut clangor tubarum. Alia subtilis, cui non est spiritus multus sicut infantium, mulierum, aegrotantium. Alia pinguis, scilicet cum spiritu multo, ut virorum.

… and so on, there follow a few more alia. When used like this, it means: “one … another … yet another etc.” (Actually, the dictionaries say so (II A) but then only offer plural examples, but here we are.)

I would read unde as unde intellegitur = ex quo intellegitur, i.e. “therefore, it follows that” or something to that effect. So the result is: “Therefore, of the voices one is pleasant, to wit, that which is delicate, dense, clear and sharp. Another is transparent and fills up an entire room, like the sound of trumpets. Another is tender and does not have much breath, like that of infants, women and the sick. etc. etc.” Note that I injected several “is” here; literally it would be more like: “A pleasant one is the one that … Another and transparent one fills … Another tender one …”

Answer 2

The first sentence is I think simply a question of a misplaced comma. It makes good sense if read as follows:

Unde vocum alia suavis est, illa scilicet quae subtilis, spissa, clara et acuta est.

That is, "For that reason one voice is sweet, namely that one which..."

The second seems more puzzling. Could sunt maybe stand for an implied sunt qui dicunt, "there are those who say"? That would make sense of the accusative and infinitive (which I think is what tenere must be), but I've never seen such an elision and I don't know if it's plausible in medieval Latin.