Unlike Welte, Hupfeld and Philipps initially, the Aeolian Company of New York used an 88-note standard scale for the Duo-Art reproducing system marketed from 1913, supplemented by perforations for expression and drive control. Distinctive are the four accent holes each in the tracker bar for bass and treble, located on the left and right above the row of holes for the notes – these control the so-called “expression box”, the expression unit. When the selector lever is set to “Standard Full Scale Rolls”, the expression control holes are switched off and the four holes below each are released for the four lowest and highest notes to give the full 88-note scale.
On the Aeolian Duo-Art, tracking is controlled by the tracking levers on the right and left.
Unlike Hupfeld or Welte, Aeolian implemented expression on the Duo-Art in 16 defined steps, i.e. not continuously. At the same time, however, Aeolian cleverly combines this with the soft pedal, so that here too – provided the instrument is very well restored and adjusted – excellent sound and expression quality are achieved in reproduction.
The Aeolian Company of New York succeeded in agreeing an exclusive contract with Steinway & Sons for the American market, so that at least 600 Steinway instruments per year were equipped with Aeolian systems. Of interest is the very extensive repertoire of Duo-Art music rolls, which includes many classical titles as well as the popular light music (blues, ragtime, etc.) in the USA.
In Germany, the Duo-Art system could hardly prevail against the powerful competition from Hupfeld and Welte. In America and England, however, it did all the more.