The two keyboards are placed at opposite ends of this 2.5 meter long instrument that weighs nearly 600 kilograms. The brilliance of the design lies in the fact that, although the two pianos are housed in one body, both have their own sets of wires, pedals and mechanism. (With a special switch, the Pleyel design also makes it possible for one of the players to operate the pedals of the other if necessary, and this of course also works the other way round.) At the same time, the casting and the resonance - an important element of the instrument - are common to both. All the sounds produced are emitted in a shared space, the overtones enrich each other, and all of this results in a warm and wonderfully full sound.Here are Pertis and Egri playing the Blue Danube Waltz:
Another interesting factoid on Pleyels from Wikipedia:
The red spruce used by Pleyel and several other top manufacturers comes from the Fiemme Valley in province of Trento, Italy. Piano-makers are extremely fussy about this. "It has to be from a north-facing tree," explained Sylvan Charles, a master piano builder who supervises the 15 workers in Pleyel's Paris workshop. "The tree has to be a certain age. The direction of the grain and the thickness are also important, but I won’t tell you any more because that is the secret of our sound." He described the Pleyel sound as "round, warm and sensual." Steinway, by contrast, is known for its bright, powerful "singing" sound.