Problem keys detected: 19
| Calculated* avg | Calculated* std dev | KMD avg | KMD std dev | KMD â calculated | |
|---|---|---|---|---|---|
| Downweight (DW) | 54.3g | 2.7g | 54.3g | 2.7g | +0.0g |
| Upweight (UW) | 27.8g | 3.3g | 27.8g | 3.3g | +0.0g |
| Balance weight (BW) | 41.1g | 1.8g | 41.1g | 1.8g | -0.0g |
| Friction (F) | 13.2g | 2.4g | 13.2g | 2.4g | +0.0g |
Best-fit downweight line:
On a well-regulated piano, downweight falls slightly from bass to treble. The best-fit line shows that fall; the scatter is the std dev of each key's downweight from the line, so the smaller it is, the more even the regulation.
* Calculated here from the measured curves, using the travel just before each key's damper lifts (DW*, UW*, BW*, F*). Keys without a damper lift use the KMD's values.
| Avg | Std dev | Keys with data | |
|---|---|---|---|
| Key travel, all keys | 10.11mm | 0.34mm | |
| Naturals | 10.34mm | 0.23mm | 52 |
| Sharps | 9.80mm | 0.26mm | 36 |
| Avg | Std dev | |
|---|---|---|
| Set-off, all keys | 8.33mm | 0.23mm |
| Set-off, naturals | 8.31mm | 0.23mm |
| Set-off, sharps | 8.35mm | 0.24mm |
| Aftertouch, all keys | 1.58mm | 0.38mm |
| Aftertouch, naturals | 1.80mm | 0.25mm |
| Aftertouch, sharps | 1.26mm | 0.27mm |
These interactive dot plots show key measurements across the entire keyboard. Hover over any dot to see the note name and exact value.
The friction, downweight and balance weight plots can show the values reported by the KMD (averaged over 2–4mm of travel), our calculated values (F*, DW* and BW*), or both. Keys tinted red have a damper lifting before 4mm, which skews the KMD values. For keys with a damper lift, we average from 2mm before the lift up to just before it, never using readings below 1mm. A hollow dot marks a window under 0.5mm wide, which has few readings. All other keys keep the KMD values.
Best-fit downweight line:
On a well-regulated piano, downweight falls slightly from bass to treble. The best-fit line shows that fall; the scatter is the std dev of each key's downweight from the line, so the smaller it is, the more even the regulation.
| Note | Key # | Problems |
|---|---|---|
| A0 | #1 | High downweight (DW*): 62.1g (>59.8g) High balance weight (BW*): 46.0g (>44.8g) Early set-off: 7.73mm (<7.86mm) |
| A#0 | #2 | High downweight (DW*): 62.0g (>59.8g) High friction (F*): 19.1g (>18.1g) Shallow dip: 9.20mm (<9.42mm) |
| C#1 | #5 | Low aftertouch: 0.75mm (<0.83mm) Shallow dip: 9.34mm (<9.42mm) |
| D#1 | #7 | Low upweight (UW*): 20.9g (<21.2g) |
| F1 | #9 | Low upweight (UW*): 20.2g (<21.2g) Low balance weight (BW*): 36.7g (<37.4g) |
| F#1 | #10 | Low upweight (UW*): 18.5g (<21.2g) Low balance weight (BW*): 36.9g (<37.4g) High friction (F*): 18.5g (>18.1g) |
| G1 | #11 | Low upweight (UW*): 20.3g (<21.2g) Low balance weight (BW*): 36.9g (<37.4g) |
| F#3 | #34 | Low aftertouch: 0.78mm (<0.83mm) |
| G#3 | #36 | Late set-off: 8.80mm (>8.80mm) |
| A3 | #37 | High downweight (DW*): 60.1g (>59.8g) High friction (F*): 19.5g (>18.1g) Late set-off: 8.89mm (>8.80mm) |
| C#4 | #41 | High downweight (DW*): 61.0g (>59.8g) High balance weight (BW*): 46.0g (>44.8g) |
| D#4 | #43 | Low aftertouch: 0.78mm (<0.83mm) |
| E4 | #44 | High downweight (DW*): 60.0g (>59.8g) |
| F#4 | #46 | High downweight (DW*): 62.6g (>59.8g) High friction (F*): 19.2g (>18.1g) |
| G#4 | #48 | Low aftertouch: 0.78mm (<0.83mm) |
| B4 | #51 | High downweight (DW*): 62.7g (>59.8g) High friction (F*): 18.8g (>18.1g) |
| F#5 | #58 | Low upweight (UW*): 20.7g (<21.2g) |
| B5 | #63 | High aftertouch: 2.34mm (>2.33mm) |
| C7 | #76 | Deep dip: 10.81mm (>10.79mm) |
Interactive Visualization: Use the slider below to explore the touchweight curve for any key on the piano.
This interactive plot shows all downweight curves (key press down) across the entire keyboard with a color spectrum from red (bass) to violet (treble). Use the slider below to highlight individual keys and see their curves in context with all others.
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