A type of reed organ developed around 1880, originally in an attempt to combine the sounds of free reeds and strings. There are several characteristics that set a Vocalion apart from the typical reed organ, however. A Vocalion operates on pressure rather than suction, with a resulting tone quality that is stronger and more pronounced than other reed organs. The organ was designed to be winded either by the performer (using the treadles) or by a calcant (organ pumper) with a hand lever. The reeds are large-scaled and speak into chambers called qualifying tubes. Just as in the finishing process for pipe organs, the individual stops on a Vocalion can be regulated note by note. Slightly enlarging the tone opening sharpens the pitch thus the reed is flatted to correct pitch. The individual sounds between the ranks are astoundingly different one from another.  

In appearance and playing 'feel', these instruments were legitimate organs.