Adjust duration of Hairpins;

[ivan . k . kuznetsov]

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?

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.
This is not good.


As an example, in the appended snippet I need to
have the decrescendo underneath the A flat start
proportionally one eight note duration after the
beginning of that A flat.

Can someone give me some pointers on how to achieve
this?

Thank you for your help and suggestions.


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

\score {
   \new Staff = "voice"
   {
     \autoBeamOn
     \numericTimeSignature

     \clef "treble"

     \time 3/4

     % voice m03
     fs'2^\mf (e'8) g'8^\mp

     % voice m04
     ([e'8]) r8 g'8^\mp ([e'8] g'8^\< [e'8]

     % voice m05
     \time 4/4
     af'2^\!^\> )  r4^\! f'4^\mp
   }
   \addlyrics{ Smear Smear Smear }
}

\layout {
  \context {

     \Score
     \override SpacingSpanner
           #'base-shortest-duration = #(ly:make-moment 1 32)  %% pg.

      proportionalNotationDuration = #(ly:make-moment 1 8) %% pg 364
  }
}