RE: multiple tempi in a single piece

[Mats Bengtsson]

Quoting Kieran Coulter <address@hidden>:

> Hi Mats,
>
> I think it belongs here,
>
> http://lilypond.org/doc/v2.10/Documentation/user/lilypond/Creating-MIDI-files#Creating-MIDI-files
>
> Where it mentions how to set the default tempo (which I assume is the 
> global tempo for most pieces that don't change tempo).

It currently describes both how to set the tempo for a full piece
within the \midi{...} block and how to set the tempo within the actual
music using the \tempo command. The details on how to use the \tempo
command without getting a printed metronome mark is described in the 
cited section on "Metronome marks".

> I would then distinguish between wanting simply for the metronome 
> markings present, wanting the markings and the correct tempo changes, 
> and wanting the tempo changes but not caring about markings (as is 
> the case for Trevor). Also, make it as clear as possible when a way 
> of working with Lilypond has the effect of managing metronome marks, 
> and when it affects the tempi within the MIDI file itself.

I'm afraid that I am too used to working with LilyPond to realize
how the current text can be improved to clarify these issues even
further. This is where you can contribute.

> So just to be totally sure,
>
> 1) you add the tempo map, "killing time" with s's, as its own voice?

It doesn't have to be a separate Voice context. It can also be in parallel
with the music within an existing Voice context:

...
\new Voice << \myMusicA \TempiA >>
...


> 2) Do you still need to add the global default tempo in the MIDI 
> block if you do this?
> tempoWholesPerMinute = #(ly:make-moment 72 4)

No!

> 3) If so, and you also explicitly add a tempo in measure 1 of your 
> tempo voice, and they are different, does it produce an error or does 
> one override the other?

That's a good question. It doesn't produce an error, but I would have
to try it out to know which one overrides the other.

   /Mats