Latencies Pianists Intuitively Learn to Handler - Quantified

Those who first learned to play on a genuine piano may have subconsciously developed Intuitive compensation for some pretty dramatic latency variations in the piano’s works.

It’s interesting to learn the variation of latency that piano action can introduce.

I found in a couple of papers taking measurements of piano actrion, including key travel times and key to hammer-sound time.

Touch and temporal behavior of grand piano actions is the most fruitful source of information.

The time interval from the key’s initial position to key “bottoming out” ranges from about:
25 ms at a forte keystroke
to 160 ms at a piano tone

(20 ms to around 200 ms was reported in another study)

Hammer contact occurs:
12 ms before key bottom contact at a piano tone
but 3 ms after the key bottom contact at a forte attack

 Results in another study:

Key bottoms out up to 35 ms after hammer–string contact in very soft tones and as early as 4 ms before in very strong keystrokes.

(I didn’t see whether the whole scale was tested, where there’s a known faster action of high notes vs low notes.)

Tests using a Yamaha Disklavier (with “prelay function” disabled)
Hammer travel time characteristics:
The time deviations extended over a range of about 110 ms for MIDI velocities between 30 and 100

The whole striking procedure needs roughly 20 ms less time with a “struck touch” compared to the “pressed touch,” both with almost identical sound intensities.


The Acoustics of the Piano

For a force of about 0.8 N, the key takes about 150 milliseconds to touch the keybed.
35.0 N (Newtons) gives a time of 1.2 milliseconds (to bottom out)

(I believe this section was looking at the hammer-string interaction at a detailed level)
"Generally, for all pianos the contact time is approximately one half the vibration period of the string for the note C4. The frequency of C4 is about 262 Hz, with its inverse being the period, 0.0038 s. This yields a half-period of 0.0019 s, or about 2 milliseconds, which is the contact time.

(It seems improbably that a controller keyboard with only an average velocity report can make for an authentic piano action simulation, polyphonic aftertouch would add a second parameter for instrument timing)

Some other Piano action studies:

Reconstruction of piano hammer force from string velocity

Pianoteq Hammer response discussion
(Video at the bottom shows the Repetition Mechanism unique to grand pianos that facilitates faster note repeats)

Characterizing the Feel of the Piano Action - Paid Access Article (free access is available)


I remember reading articles ( practical electronics, electric piano) that stated impact velocity was the ‘Only’ parameter to affect tone. Perhaps like, 44.1khz is enough, we may have built our technologies on one or two false assumptions!

From the perspective of someone playing the approach to how emotion is transferred into physical movement which is then rendered by a ‘device’ (Sorry Steinway…) is all good solid learning !