Re: Adjust duration of Hairpins;

[Kieren MacMillan]

Hi Ivan,

> I have been reading the archives, and if I understand
> correctly, the _only_ way to make a hairpin crescendo
> or decrescendo last a duration that is shorter than an entire
> whole or half note is to add a pseudo voice of "invisible
> rests" and notate your hairpins to the pseudo voice.
> Is this really the only way?

No:

\version "2.12.3"
\include "english.ly"

\score {
  \new Staff = "voice" {
    \autoBeamOn
    \numericTimeSignature
    \dynamicUp
    \clef "treble"
    \time 3/4
    fs'2\mf (e'8) g'8\mp   % m03
    ([e'8]) r8 g'8\mp ([e'8] g'8\< [e'8]   % m04
    \time 4/4 af'2*1/4\! s8*3\>) r4\! f'4\mp   % m05
  }
  \addlyrics{ Smear __ Smear __ Smear __ Smear }
}

\layout {
  \context {
    \Score
    \override SpacingSpanner
      #'base-shortest-duration = #(ly:make-moment 1 32)
    proportionalNotationDuration = #(ly:make-moment 1 8)
  }
}

> If so, I find that adding this pseudo voice causes all
> kinds of unwanted consequences such as adjusting vertical
> positions of rests and stem directions in the actual music.

Then you're doing it incorrectly — here's the same snippet, using a "pseudo 
voice" for the dynamics:

\score {
  \new Staff = "voice" {
    \autoBeamOn
    \numericTimeSignature
    \dynamicUp
    \clef "treble"
    \time 3/4
    << { fs'2( e'8) g'8[( } { s2\mf s8 s8\mp } >>   % m03
    << { e'8]) r8 g'8[( e'8] g'8[\< e'8] } { s4 s\mp s\< } >>   % m04
    \time 4/4 << { af'2*1/4 s8*3) r4 f'4 } { s8\! s8*3\> s4\! s\mp } >>   % m05
  }
  \addlyrics{ Smear __ Smear __ Smear __ Smear }
}

\layout {
  \context {
    \Score
    \override SpacingSpanner
      #'base-shortest-duration = #(ly:make-moment 1 32)
    proportionalNotationDuration = #(ly:make-moment 1 8)
  }
}

As you will see, there are no "unwanted consequences".

A couple of other hints:
1. You don't have to (and, indeed, shouldn't) use ^\mf to attach your dynamics 
— if you want all your dynamics above the staff, you should change it globally 
with \dynamicUp (as I did in these snippets).
2. You should review your use of brackets and parentheses (note how I've 
adjusted them in these snippets): they do not follow Lilypond conventions, and 
may produce "unwanted consequences" someday.

Hope this helps!
Kieren.