Piano Pedals Explained: Sustain, Soft, and Sostenuto
Pedals are the least-taught and most-abused part of piano technique. Used well they are central to how the instrument sounds. Used carelessly they blur everything.
The sustain pedal (right pedal)
This is the one you will use constantly. It lifts all the dampers, so strings keep ringing after the key is released — and, importantly, other strings resonate sympathetically, which is what gives a piano its characteristic fullness.
What it does: sustains notes after release, and adds sympathetic resonance.
What it does not do: make a passage legato. Legato comes from fingering. Pedal used to cover gaps in legato produces a muddy sound and hides a technical problem rather than solving it.
Basic pedalling
Rhythm pedal (pedal with the harmony): press as the harmony changes, release and re-press at each new chord. This is the default pattern and it keeps harmonies clear.
Legato pedal: release *after* the new note is struck, briefly, so there is no audible gap but also no accumulation of harmony. More advanced and more precise.
Half pedal: partially depressed, so dampers graze the strings. Produces a subtle sustained shimmer. Requires a pedal that supports continuous position, not just on/off.
Common mistakes
- Holding through everything — harmonies pile up into mud
- Pedalling to hide poor legato — masks the problem, sounds worse
- Pedalling too early — blurs the previous harmony into the new one
How to practise it
Play the passage with no pedal at all until the notes are clean, then add pedal deliberately. If it falls apart without pedal, pedal is not the solution.
The soft pedal (left pedal)
On an acoustic grand, the una corda mechanism shifts the action so hammers strike fewer strings — a change in *timbre* as well as volume. On uprights it moves hammers closer, reducing volume mainly. On digital pianos it is usually a volume and sometimes filter reduction.
Use it for: genuine dynamic contrast in quiet passages, and tonal colour. It is not a substitute for playing quietly — pieces marked *piano* are usually meant to be played quietly with the fingers, not played at normal volume with the soft pedal down.
The sostenuto pedal (middle pedal)
The least used and least understood. It sustains only the notes held down at the moment you press it; notes played afterwards are unaffected.
This is different from sustain, which affects everything. It lets you hold a bass note or chord while playing other material cleanly above it — useful in some Debussy, Ravel, and contemporary repertoire.
On uprights the middle pedal is often a practice pedal (mutes the sound) rather than true sostenuto. On most digital pianos the middle pedal is assignable. Check what yours actually does before relying on it.
Pedal on a digital piano
Two things matter:
Does the pedal support continuous position? A cheap footswitch is on/off only, so half-pedalling is impossible. A pedal that reports continuous values (usually included with mid-range and above instruments) supports it.
Does it respond properly? Some included pedals are simple switches. If pedalling feels like it either does nothing or does everything, this is likely why.
Pedal notation
- Ped. — press the pedal
- Asterisk or a marking like ✽ — release
- A long horizontal line under the staff — hold for the duration, with breaks indicated
- *una corda* — soft pedal on; *tre corde* — off
When no pedal markings appear, pedalling is left to the performer. A good default: pedal with the harmony at a moderate level, and clear the pedal at phrasing points.
What to listen for
Good pedalling is largely inaudible — you notice fullness, not the pedal. If you can hear the pedal working, it is probably too much. Record yourself; pedalling problems are much easier to hear on playback than in the moment.
A practical order
- Learn the passage clean with no pedal
- Add pedal with the harmony
- Listen for blurring at harmony changes and adjust
- Only then consider half-pedalling or more subtle effects