Buying guide
Polyphony Without the Hype
Why a piano with 88 keys can need more than 88 voices
Polyphony is the sound engine's capacity to sustain simultaneous voices. It is not simply the number of fingers on the keyboard. Hold the sustain pedal and earlier notes can continue sounding while you play new ones. The published maximum describes an engine limit under the manufacturer's conditions; it does not measure the realism of the piano sample, the quality of the action or the power of the speakers.
Voices do not always equal played notes
Implementations differ. Stereo samples, layered instrument sounds and other engine components can consume resources differently. A piano-and-strings layer asks the instrument to reproduce more than one sound for a performance gesture. MIDI song playback may share the internal sound engine with live playing. An audio backing track is a different case and should not automatically be counted as MIDI-generated piano voices. Resonance may be sampled or modelled; there is no universal rule that every resonance effect halves a quoted number. Use the model's manual for exact restrictions.
What note stealing sounds like
When an engine runs out of available voices, it must free resources. Depending on its allocation rules, some existing sound may be shortened or removed. You might hear a sustained bass note disappear while a dense passage continues above it. It is not safe to assume every piano always cuts the oldest note first. Intelligent allocation and natural decay can make the limit hard to notice, while a sustained, layered texture may reveal it. Musical context matters more than an isolated number.
How to compare 64, 192 and 256
These numbers describe capacity, not an overall ranking. More headroom can be useful for layered playing and sustained textures, but paying for a larger maximum does not necessarily improve a simple solo-piano exercise. Equally, declaring that nobody needs more than a particular number ignores different engines and playing styles. Check qualifications: Roland lists effectively unlimited piano polyphony for specified solo tones on the FP-90X, alongside a separate limit for other sounds. Removing the qualification would make a comparison misleading.
Test the music you intend to play
Use the actual piano voice and normal pedal technique. Hold a bass note, then play the denser part of a piece and listen for an abrupt loss of sustain. Repeat with a layer or MIDI accompaniment only if you will use those features. Keep volume consistent and listen with good wired headphones so room noise does not hide the decay. Excessive pedal holding can create a stress test, but it may not reflect your music; record both the test and a representative performance.
Spend for the whole experience
Once an instrument handles your repertoire cleanly, action control, pedal response, sound preference and usability usually make a more useful next comparison. A larger number cannot rescue a key action you find uncomfortable. Start with the instrument's limitations, not a minimum invented for every buyer. Our Compare table preserves model-specific qualifications and marks unknown fields rather than turning an unverified value into zero.