Here’s another good question and the answer will vary slightly depending on what type piano you have and who the manufacturer was.
GRAND PIANO PEDALS
Typically, on a grand piano, the left pedal is a soft pedal, the center pedal is usually a sostenuto pedal, and the right pedal is always the sustain pedal.
Soft Pedal. The left pedal is typically a soft pedal. On grands, it most always works by shifting the entire action to the right just a fraction of an inch to the right. This allows the hammers to hit only 2 of the 3 strings in the treble, and one of the two strings in the tenor. The bass, having only one string, will still sound since they are wider strings and the shift isn’t enough to move the hammer off the string. It will hit the hammer striking surface a little off center, but that allows the string to contact the hammer at the part of the hammer head that should have softer, less compacted felt, resulting in a softer sound.
Note: some lesser expensive grand pianos may not have this feature.
Interestingly enough, I’ve been asked by customers to remove that extra space at the far right end of the keyboard between the last key and the cheek block, (not knowing of course what it’s purpose was) but this space is there on purpose in grands so that your shift pedal (soft pedal) will work.
Sostenuto pedal. The center pedal is usually the sostenuto pedal, and found mainly on good quality grands as well as professional grade uprights. It is a pedal that is not often used except maybe in certain types of classical music. It sustains ONLY the notes you just played, but not the ones after. So, for instance, if you played a C E G major chord and held the keys down, then press the sostenuto (left) pedal and hold it, the chord you just played will still be sounding while all the other dampers are down on all the other notes of the piano. Now, while that chord is sounding, you can go on and play the piano as usual, even using the sustain pedal, and even playing the notes of that same chord. What it amounts to is that it holds up only the dampers of keys that were played, and will keep only those up as long as the pedal is depressed. The regular sustain pedal will still operate all the other dampers as usual.
Note: some lesser expensive grand pianos may not have this feature, even though they have a center pedal. In that case, it will likely just raise the bass dampers which mimics a sostenuto, but really it’s not a true sostenuto (like you find on most uprights, as will be explained later).
Sustain Pedal. The right pedal is the sustain pedal and is the most used pedal on the piano. Simply, this pedal raises all the dampers off the strings to allow them to resonate freely, even after the key has returned to it’s rest position. Any number of notes can be sustained at the same time since all the dampers in the piano (using this pedal) all lift at once.
UPRIGHT PIANO PEDALS
Typically, the left pedal is usually a soft pedal, the center pedal is either a “faux” sostenuto pedal (will explain later) or a practice pedal (extra soft lock-on), and the right pedal is always the sustain pedal.
Soft Pedal. The left pedal is typically a soft pedal. On uprights, it works by either lifting the hammer rest rail closer to the strings to shorten the distance the hammer must travel, thus softening the blow, or it will lower a felt rail between the hammers and the strings to muffle the sound.
You may notice that when the hammer rail is moved forward, lost motion is introduced in the action making it more difficult to play and control. This doesn’t happen with the felt rail mufflers, although, they will certainly wear over time.
“Faux” Sostenuto Pedal. The center pedal is usually a “faux” sostenuto, or fake sostenuto. That’s what I call them, anyway. True sostenutos, like you would see on most grand pianos and some more professional model uprights, are too expensive to include in most uprights. Therefore, they opted to make a split damper system that would mimic a real sostenuto (although it doesn’t do well at it at all, in my opinion).
Most upright center pedals will lift only the bass dampers off the strings, allowing you to play the rest of the piano (mid to upper section) as normal. This causes the chord tones you play while pressing the pedal to ring sympathetically in the bass. Again, this is not a true sostenuto. Refer to the grand sostenuto function above.
Some of your more expensive uprights DO have a true sostenuto systems. To check, lift the lid and watch your dampers as you press the left pedal. If the bass dampers lift off the strings but the other half of the dampers in the piano don’t, then you do not have a true sostenuto.
On other uprights, the middle pedal is a practice pedal (with a locking option) which makes the sound extremely quiet beyond the standard soft pedal. This is often achieved by dropping a felt cloth between the hammers and the strings when the practice pedal is depressed. So on these pianos, you would have two soft pedals, the left pedal (probably which moves hammers closer to strings) and the center locking pedal (which lowers a felt rail between hammers and strings).
Sustain Pedal. The right pedal is the sustain pedal and is the most used pedal on the piano.
Simply, this pedal raises the dampers off the strings to allow them to resonate freely, even after the key has returned to it’s rest position. Any number of notes can be sustained at the same time since all the dampers in the piano (using this pedal) all lift at once.
My Pedal doesn’t seem to do anything!
You may be absolutely right! Sometimes you will have a pedal that actually is for looks and has no function. Really. Less expensive pianos sometimes put “dummy” pedals on for looks and selling appeal.
If one or more of your pedals doesn’t seem to work, it could a “dummy” pedal, as mentioned, or it may have been accidentally disconnected, or maybe it was forgotten to be reconnected when the piano was serviced or moved. You may be able to remove the lower board on your upright and visibly see if any of the pedal dowel rods are disconnected. They aren’t hard to reconnect. Or, mention it to your piano technician and they’d be happy to fix it for you, probably for no charge if done at the time of a regular tuning.
If you still have questions about the function of your pedals, have your technician explain to you how your pedals function on your particular piano.
Until next time….make a joyful noise!