Re: Span_dynamic_performer

[Stephen]

Searching for the performers and engravers works for learning how to insert 
usable scheme code in the lilypond files, but the code that actually decides 
which midi volume levels to set where is not in the performer. For instance, 
absolute-volume-alist:

#(set! absolute-volume-alist
     (append
     '(
("sf" . 1.00)
("fffff" . 0.95)
("ffff" . 0.90)
("fff" . 0.85)
("ff" . 0.80)
("f" . 0.75)
("mf" . 0.68)
("mp" . 0.61)
("p" . 0.55)
("pp" . 0.49)
("ppp" . 0.42)
("pppp" . 0.35)
("ppppp" . 0.28)
)
     absolute-volume-alist))

can be set to determine the relative values of the absolute dynamic marks, 
but midi volume levels do not range from 0 to 1. There must be a place where 
the values are converted to midi volume values, but it is more difficult to 
trace which function is using the info in the absolute-volume-alist than it 
is to search for the engravers and performers in the sources.

Stephen

----- Original Message ----- 
From: "Erik Sandberg" <address@hidden>
To: "Stephen" <address@hidden>
Cc: <address@hidden>; <address@hidden>
Sent: Sunday, April 10, 2005 3:19 AM
Subject: Re: Span_dynamic_performer


> On Sunday 10 April 2005 05.18, Stephen wrote:
> > It has been my experience that visually it looks better to connect 
> > absolute
> > dynamics with a hairpin or to say it the other way around, to connect the
> > hairpin to an absolute dynamic. I am not trying to be difficult. If what
> > you say is true, what the hairpin engraver has been written to perform
> > optimally the hairpin performer has a bug in.
>
> Yes, it is certainly a bug. midi-cresc-silence.ly in the bug repository.
>
> > Usually a hairpin dynamic is placed between one or two absolute dynamics 
> > so
> > that the performer of the music knows to gradually shift from one dynamic
> > to the other. Usually in printed music the dynamics and hairpins are 
> > lined
> > up with each other vertically in this case. I learned that an easy way to
> > make a hairpin line up with an absolute dynamic is attach the start or 
> > end
> > of the hairpin to the same note as the dynamic. So if this messes up the
> > midi, it is very unfortunate, 'cause it is more important to makr it look
> > good.
>
> There is one possible workaround:
>
> Create 2 scores, one for paper output and one for midi output. In the midi
> score, add an extra s64\mf before the beginning of each voice. (it's dirty
> but works)
>
> > I am not angry, it just takes a lot of words to make clear what I mean.
> > Often the purpose of a hairpin is to modulate the volume between two 
> > given
> > dynamics. Clearly the problem is that the hairpin modulates the volume 
> > from
> > its start to its endpoint, but really, it should never modulate at its
> > endpoints anyway. When a performer sees a hairpin, he knows to bring it
> > from the dynamic he is already playing at the start of the hairpin to
> > another absolute dynamic at the end of the hairpin. So the modulation
> > should never include, say, the first note of a hairpin. If there are only
> > two notes, it should only change the dynamic of the second note. If the
> > hairpin is attached to only one note, it should only change the dynamics 
> > of
> > the notes following the hairpin. Etc.
> >
> > Again, I am curious to know which file this code is in in the sources.
>
> I am not a lilypond hacker (just an user, bug admin and hacker wannabe).
> However, I could suggest you to start with a
> grep Span_dynamic_performer ly/* scm/* lily/*
>
> Erik