Hugo Riesenfeld, conductor of Roxy Theatre Orchestra, was commissioned by American impresario Samuel 'Roxy' Rothapfel to adapt the Bizet for all screenings of Carmen nationally. This is a tremendous task as each theatre, large and small, has vastly varying degrees of sizes and utterly different instrumentation.
Being the talented arranger that he was, however, he made it in such a way that an ensemble of any size or combination could perform it without the loss of a single voice or line, so long as you had a pianist. Which is why one could hear the same exact score in New York, orchestrally, as they could in Omaha, Nebraska, with a piano, trumpet and a triangle. It was after Carmen that this technique became common practice among all silent film composers, and beyond. The score literally traveled with the film reels to each theater that exhibited it, and any combination of players could perform it. It is about this time that film music in America was starting to be recognized for it's potential value as an artistic component of film.
I restored this score in 1995, incorporating the period-performance practices of the 1910's and 20's, most of which has died out with the players who performed them originally. These techniques can include audible string shifting and burnished vibrato, hopped-up tempi, acorn mutes for the brass, etc. All of which is absolutely necessary to provide an emotionally accurate rendition of this score. This holds true for all period music, from the middle ages onwards.