Double Keyboard Piano

The Moór double keyboard piano (also called the Moór Duplex Piano or Bechstein–Moór piano) is one of the most unusual experiments in piano design from the early 20th century—a hybrid between piano, organ thinking, and pianistic technique innovation.

It was invented by the Hungarian composer and pianist Emánuel Moór, who was active in the late 19th and early 20th centuries and was strongly influenced by Liszt’s virtuosic tradition. Moór’s idea was not to change the sound of the piano, but to radically change how it is played.

Credit: Museumsinsulauner Wikicommons

What makes it “double”?

The instrument has two stacked keyboards:

• A lower keyboard (standard 88 notes)

• An upper keyboard (usually around 76 notes)

Both keyboards control the same set of strings and hammers, but the upper manual is arranged so that notes sound an octave higher.

This creates a system where a pianist can:

• Split difficult passages between hands and between keyboards

• Play wide intervals (like tenths or two-octave spans) more easily

• Trigger octave doubling via a coupling pedal, similar in concept to organ registration

The musical idea behind it

Moór’s goal was to make extreme virtuosity more “ergonomic.” Romantic piano music—especially works by composers like Chopin, Liszt, and Rachmaninov—often demands large leaps, rapid octave passages, and hand stretches that can be physically limiting.

With the double keyboard:

• A passage normally requiring large hand stretches can be redistributed between two manuals

• One finger movement can produce a richer, octave-doubled sound

• The performer gains what one contemporary reviewer described as “almost four-hand independence” on a single instrument

Who built them?

Although Moór designed it, he did not manufacture it alone. Several major piano makers built versions in small numbers:

• Bösendorfer

• Bechstein

• Steinway

• Pleyel

• Chickering

The most refined instruments were often labelled “Bechstein–Moór Duplex” or similar.

Why it didn’t survive

Despite interest, the design never became mainstream. There were several reasons:

• Pianists would have to relearn fundamental technique

• Manufacturing was complex and expensive

• The mechanism made the action heavier and more demanding

• Musical culture did not shift enough to require it

In total, only around 60 instruments were ever built, and most are now museum pieces.

A striking historical moment

The Moór piano did have a brief public life in the 1920s–30s. Pianists such as Winifred Christie-Moór (his wife and major advocate) performed and demonstrated it internationally, including high-profile concerts in Europe and the United States.

At the time, it was often described as sounding like:

“a piano with extra hands”

Why it still matters

Today the Moór piano is less a practical instrument and more a fascinating idea in keyboard history. It represents:

• A radical attempt to redesign piano technique

• A bridge between organ-like layout thinking and piano touch

• One of the few serious 20th-century mechanical re-imaginings of the piano itself

For historians and performers, surviving examples are important because they show that the piano was once considered re-inventable, not fixe