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## Re: feathered beam calculations

 From: Michael Gerdau Subject: Re: feathered beam calculations Date: Tue, 18 Dec 2018 17:19:49 +0100 (CET)

```> I understand your math now but I do not understand how you began to know how
> to use math from the beginning. How did you determine which note NEEDED the
> math to it? Is there a sort of study sheet where we can look to find out
> which notes need math for each time we use?

I'm not sure what you are after and maybe what follows is as obvious to you as
it is to me, but in case it isn't here I go:

For easier reference I'll repost one of Harm's examples:
\relative d {
\clef bass
\override Beam.grow-direction = #RIGHT
\featherDurations #(ly:make-moment 3/4)
c16*4/3[ d e]
c32*2*4/3[ d e]
c64*4*4/3[ d e]
c128*8*4/3[ d e] |
\revert Beam.grow-direction
cis1 |
}

c16/c32/64/128 means 2/3/4/5 feathers respectively

Each group is expected to last one quarter note which is denoted by "4".
Since we start with a 1/16th we have to mutliply by 4 to get back to 4.
There are 3 notes in each group which means we add the notelength 3 times which
is another way of saying we multiply by 3. Hence we have to divide by 3 to make
the whole group 1/4 note in length again.

A very similar argument goes for c32 (*2 == c16), c64 (*4 == c16) and c128 (*8
== c16).

If you were looking for something else when you asked for the math then please
be more specific.

Kind regards,
Michael
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