I came across this over at the Boston Wagner Society and thought that if you were in the area you might be interested. A little background on this is available over at the excellent Monsalvat in an article named How Humperdinck Saved the Day.
I have also included an youtube video of Humperdicnks piano transcription for 4 hands of the Parsifal prelude. Information below as found at the BWS. For full details click the link at the bottom of the page
“The Unknown Wagner-Humperdinck Collaboration:
The Premiere (since 1882) of Humperdinck’s
Musical Contribution to Parsifal”
A Lecture-Demonstration by Jeffrey Brody
Sunday, April 22, 3 p.m.
Maestro Brody, conductor,
composer, pianist, and coach, will speak about Humperdinck’s musical
contribution to Parsifal. Humperdinck’s addition came about in an
unusual way. At the opera’s 1882 premiere in Bayreuth, Wagner needed a
longer Transformation Scene. Humperdinck, who was Wagner’s assistant,
stepped in and wrote a few extra bars, which solved the technical
problem of the transition.
Humperdinck’s addition to
Parsifal languished in obscurity until Maestro Brody, with the help of
an archivist at Bayreuth, obtained it from the University of Frankfurt.
In addition to listening to
Humperdinck’s contribution, we will watch various Transformation Scenes
from different productions of Parsifal.
More at the Boston Wagner Society