laissezVibrer

[Peter Buhr]

I want to specify a duration (tie length) for \laissezVibrer as in:

  a4\laissezVibrer{1}

meaning put a tie of duration whole-note on the 1/4 note "a". Knowing how long
to let a note ring seems essential to describe the music for a player. I
searched the web and found others asking a similar question but I could not
find a good answer.  I appreciate that it is my problem if this tie bangs into
something downstream.