THE POLICE QUARTET was an early Vitaphone film. This Warner Brothers short apparently was one created using a very complicated system through which an accompanying record was synchronized with a movie camera. There were several serious setbacks for such a system (such as if a film skipped--it became out of sync for the rest of the film plus the records quickly wore out--and 20 showings was the normal life-span of the records) and even though it produced excellent sound, it was eventually replaced. The last of the Vitaphone films were made in 1930, then the studio switched to the standard sound-on-film system.
Like so many of the Vitaphone shorts, this one was filled with singing. However, I gotta be blunt--this quartet was not one of the finest Vitaphone productions I've ever seen and heard. While some of the later numbers they sing (such as the one about the chicken thief) are pretty good, many are downright awful--proving that the folks at Warner Brothers would record anything for these sound experiments!! The cops must have been nice fellows, but their singing is strictly for a local amateur show and they had very little charisma. Note that the bass had a nice voice and his higher singing voiced comrades could have used some voice lessons. As a result, this one is a bit of a chore to watch even though it IS important for historical reasons.