Yamaha U1TA UPRIGHT PIANO.

Now for what makes it “TransAcoustic.” The digital sound engine drives two transducers—located on either side, as shown in the main photo above—that convey vibrations to the wooden soundboard. This idea isn’t new in itself; “vibration speaker” is the generic term and piano builders have experimented with it before (though not always in products that made it to market). The trouble is, physically mounting a speaker onto a soundboard is the last thing you want to do, as it dampens the soundboard’s vibration and can lead to damage if the wood contracts or expands over time. The traditional other option is pointing a speaker that’s mounted on something else at the soundboard. No matter how close it is, you still lose energy in the air between transducer and soundboard, and things won’t sound right.

Yamaha’s solution is basically to split the difference. Only the voice coil—the little wire-wrapped cylinder from which the rest of a conventional speaker funnels out—is mounted on the soundboard itself. The coil is so lightweight that it doesn’t cause any dampening issues. The magnet and other heavy bits are mounted on the surrounding bracing, such that the voice coil can surround the magnet without actually touching it. When the speaker is energized, the voice coil’s movements vibrate the soundboard without weighing it down. In effect, the soundboard plays the role of “speaker cone.”