Use of the una corda pedal
Image 1
When depressed, the una corda pedal slides the key frame laterally a few millimeters, so that the hammers strike one string less per string course (see Image 1).
On the lowest string, it hits the string(s) differently, but still so that it results in a slightly softer sound.
If the una corda is used in combination with a ‘non-unison string course scordatura' or a ‘piano preparation' affecting especially the left-out string, one has the possibility of changing timbre both suddenly and - due to slight inaccuracies in most instruments - also quite gradually.
Be aware that, if the instrument is not in top shape, one will often hear some resonance, though very soft, from the left-out string when the una corda pedal is depressed.
If a hammer strikes all of its strings while the una corda pedal is pressed all the way down, the pianist should ask the piano tuner to adjust the keyboard placement[1] so that the left pedal will work effectively.
Do not forget that the dynamics naturally decrease slightly when using the una corda pedal.
Experimenting with the use of left pedal
In general, the same little motif of 3 tones/keys has been tested in different dynamics (forte and piano) and in 3 different ranges;
middle range, very low range and the very high range.[2]
Una corda vs tre corde
1. Una corda, forte
2. Tre corde, forte
3. Una corda, piano
4. Tre corda, piano
| The una corda-string is raised by an 1/8-tone. |
||
|---|---|---|
|
Low range |
Middle range |
High range |
| The una corda-string is raised by a 1/6-tone. |
|---|
|
Middle range |
Gradual changes between una corda and tre corde.
| The una corda-string is raised by an 1/8-tone. | ||
|---|---|---|
| Low range | Middle range | High range |
|
Loud, |
Loud |
Loud |
|
Soft |
Soft |
|
Examples of works including this technique:
- Jon Øivind Ness: Rawgabbiting
- Eivind Buene: Three Studies for Microtonal Piano
- Øyvind Mæland: Boiling Web
- On a Steinway, this is adjusted by a screw on the right keyblock (just to the right of the C8key), but in order to access this screw, one must first remove the keyslip.
- Note that the keyboard placement was not adjusted for the recording of these samples, something which becomes very clear in the examples of the very low range played forte, and shows that the una corda function on this instrument was rather inaccurate.