For the past several years, the trend in musical theatre has been to reduce the size of orchestras. This began with synthesizers replacing strings, and has finally come to be everyone being replaced by a "virtual orchestra," a cool name for a really big, sophisticated, synthesizer.
One of the great things about the MUNY in St. Louis, (and there are many, many great things there, management, crew, cast, venue, traditions, it is a long list) is the use of the original orchestrations for the shows. No tracks, but real voices on stage and real musicians in the pit. That combination always makes better, more exciting, theatre.
I think that reviews of two current Saint Louis productions, Cats at the MUNY and Promises, Promises, make my point.
From Chris Gibson's review of Cats at the MUNY in Broadway World 7.21.10
“James Cunningham's wonderful music direction, which neatly replaces the dated sounding synthesizers with a full-bodied orchestra, and revitalizes the score in the process.”
From Dennis Brown's Review of Promises, Promises at Stages St. Louis in the Riverfront Times 7.21.10
“But because this is Stages, the music is prerecorded. The playbill calls this "electronic reproduction" and "orchestral realization." Whatever you choose to call it, the resulting sound is about as exciting as a ride in a 1950s elevator listening to Muzak.”
The critics seem to agree, live musicians make better theatre. If you are in St. Louis, make sure to come out and support world class musical theatre at the MUNY. It really doesn't get any better.