Hi GA,
I am looking for the name of a film mz father saw in the 50s or the 60s.
It is the story of an orchestra conductor who plans the murder of his
wife, in four acts. In the first act you see him conducting a Brahms
(?) symphony and plotting three scenarios. This part is set in a
serious mode. The next three acts are his desperate attempts to
implement the plan. But it all goes wrong - these parts are very
funny, as far as my father can now remember.
I dont hvae much else on this one. Looking forward to hearing from you,
Thanks,
Can1972

Hi Can1972!

I believe the movie that your father saw is the 1948 film
?Unfaithfully Yours? starring Rex Harrison.
http://www.imdb.com/title/tt0040919/maindetails


Plot Summary for Unfaithfully Yours (1948)

?Sir Alfred De Carter suspects his wife of infidelity. While
conducting a symphony orchestra, he imagines three different ways of
dealing with the situation. When the concert ends, he tries acting out
his fantasies, but things do not go as well in reality as they did in
his imagination.?
IMDb
http://www.imdb.com/title/tt0040919/plotsummary


Here?s another summary from Film Site:

?The splendid, fine farce is the tale of British, middle-aged symphony
orchestra conductor Sir Alfred de Carter (Rex Harrison) who suspects
his lovely wife Daphne (Linda Darnell) of infidelity. While leading
his orchestra in three different pieces, he elaborately daydreams
various forms of revenge, each one accompanied by a classical music
piece.?

?During the conducting of Rossini's Overture to Semiramide, Sir Alfred
imagines himself, in a complex and ingenious fantasy, murdering Daphne
and plotting to frame and convict Tony (Kurt Krueger), his own
suspected young private secretary, for the crime. While performing the
second number, Wagner's reconciliation theme from Tannhauser, Sir
Alfred fantasizes about writing Daphne a large check, forgiving the
young couple, and allowing his wife to run off with her young lover.
And while conducting the third piece - the finale, Tchaikovsky's
Francesca da Rimini overture, he sees himself challenging Daphne and
Tony to a fatal game of Russian roulette. While the plans work
perfectly in his mind, he stumbles and bumbles his way through the
preparations in real life.?
Film Site
http://www.filmsite.org/unfa.html


There are 7 new and used copies of this film available at Amazon
http://www.amazon.com/gp/product/offer-listing/B000006GE5/ref=dp_pb_a//102-5202181-6349765?condition=all


Amazon Customer Review:

?This movie was an absolute classic! I found it really interesting
that he plotted out how to deal with his wife's infedelity while he
conducted an orchestra. The things he plotted, though, were somewhat
gruesome to watch, I must say. However, I have to say that the scenes
in which Rex's character was trying to carry out his terrible scheme
were very funny, and delightful to watch.?
Amazon
http://www.amazon.com/exec/obidos/tg/detail/-/B000006GE5/ref=ase_imdb-adbox/102-5202181-6349765?v=glance&s=video


Search criteria:
I searched the IMDb for plots using the keywords orchestra,  murder and wife 
http://www.imdb.com/

I hope this is helpful. 

Best regards,
Bobbie7