Why pianos go out of tune?
Aside from initial settling, temperature and humidity are the main causes of pitch change. That's because the piano's main acoustical structure, the soundboard, is made of wood. While wooden soundboards produce a wonderful sound, they also react constantly to climate changes.
As the relative humidity goes up, the soundboard swells, increasing its crowned shape and stretching the piano's strings to a higher pitch. Then during dry times the soundboard flattens out, lowering tension on the strings and causing the pitch to drop.
The drop in the summer or when the heating is high in the winter tends to exceed the rise during cold humid times, so the net result is a drop in pitch each year that the piano isn't serviced.
This is why it's important to have a piano serviced regularly, ideally each season.
How is a piano tuned?
Although there are only 88 keys, a piano has over 200 strings - one per note in the low bass, two per note in the upper bass, and three per note in the treble.
The average tension per string is approximately 160 lbs. The combined tension of the strings is 15 to 20 tons, or almost 30 tons in a concert grand piano.
The strings gradually increase in thickness and length from treble to bass, and bass strings are also wrapped with copper.
Most of the piano has 3 thick steel strings at high tension struck by a felt hammer. These are called ‘Trichords’. The Piano Tuner places a wedge between 2 of the 3 strings and tunes them one string at a time. The other 2 strings are then tuned to exactly the same pitch. These are called ‘Unisons’. The higher end of the bass has 2 copper wound strings tuned together in ‘Unison’ and the low bass has 1 thick copper wound string, a ‘Solo’ string.
All of the strings are held at high tension by a 2 inch long tuning pin which has been hammered into a large laminated block of wood until the pins are very tight. The Piano Tuner turns these pins with a tuning crank, just like a guitarist turns the pin that the guitar strings are wound around, until it is in tune.
On average, it takes a professional piano tuner about an hour to tune all the strings on a piano.
What are the essential steps to tune a piano?
- Removing external piano panels.
- Brining a mid-treble note to the pitch of a standard tuning fork (commonly top C or middle A).
- Putting adjacent notes in tune relative to the first note tuned. The most pure musical interval is the octave, followed by the 5th, the 4th then the major 3rd. So, for example, once top C is tuned to a standard C tuning fork, top C could be used to tune middle C, then middle C could be used to tune the note one 5th above (middle G), then middle G (G4) to tune G3, G3 to tune D4, D4 to tune D3, D3 to tune A3, and so on. The next note would be E, which can be compared with C to see if the interval of a 3rd also sounds right - this is the way tuners check their progress. The sequence of 5ths is a cycle: C, G, D, A, E, B, F#, C#, G#, D#, A#, F, C returning to C.
- When an interval is used to tune one note to another in the mid-treble, a wedge is used to stop the sound of two of the strings while the third string is tuned (remember in the mid-treble there are 3 strings to each note). After the first string of a note has been tuned, the other two are tuned to the first string to create a perfect unison.
- After the mid-treble section (known as the temperament) has been tuned, the rest of the piano can be tuned relative to the mid-treble using ascending and descending intervals of an octave.
- It's customary for a tuner to give the piano a quick checking over afterwards, to check octaves especially round the bass-treble break-point, and to check that none of the unisons have moved.
- After the tuning is complete the piano's external panels are put back on.
How do I look after my piano?
Keep your piano in tune. It was specifically designed to be tuned to the international pitch standard of A-440 cycles per second.
Your piano will sound its best and give you the most pleasure when it is tuned regularly and kept in proper playing condition.
Keep your piano clean. Keep the keyboard covered when not in use to prevent dust from accumulating (although ivory keys need some exposure to light to prevent yellowing).
Clean keys by occasionally wiping them with a damp cloth and drying them immediately. If accumulated debris can't be removed with a damp cloth, try wiping the cloth on a bar of mild soap or moisten with dishwashing detergent before wiping.
Do not use chemicals or solvents to clean piano keys. Call a professional to remove anything from the keys that you can't wipe away. Using chemicals and solvents can irreparably damage your piano.
To maintain the piano’s finish, you may wipe the case with a damp cotton cloth to remove fingerprints, or polish with a reliable emulsion-type, water-based solution following the manufacturer's instructions. Avoid aerosol spray polishes that contain silicone.
The maintenance of the inner workings of the piano and regulation should be left to a professional Piano Tuner. Resist dusting the inside of your piano, oiling the moving parts, or using moth or insect repellents.
Try to maintain a fairly consistent temperature and humidity control in the room where your piano is placed. It's important to keep your piano away from heating - central heating dries out wood as well as people and some humidity is a good idea in the home.
An easy and free way to humidify your piano is for the Piano Tuner to place a tall jar in the base of the piano and show you how to remove the panel below the keyboard to fill the jar with water.
You'll be amazed how much water evaporates in just a few days when the heating is on high. Alternatively, a more effective method is to buy an electric humidifier. Ask us for information on the best types to buy.
What is the right environment for my piano?
Please do not put your piano anywhere near a radiator other sources of heat, or in direct sunlight, or in a greenhouse. If you do, it has a very short life expectancy. Aim to keep the piano's environment at a stable relative humidity of between 30-60%. Harsh environmental conditions can cause loosening of tuning pins - the damage could run well into the $1000's. Harsh conditions are also the main reason that pianos come to the end of their life prematurely.
The most unfortunate victim of these conditions is the wrest plank (or pin block). Each string is wound around a long tuning pin, which is deeply embedded into this very thick, cross-laminated plank of wood. Wood expands when it gets wet, and shrinks when it dries. If the wrest plank dries up, it'll shrink and this will enlarge the holes into which each tuning pin is embedded. Eventually, the tuning pin has no grip at all, and needs to be replaced for a thicker one. If too many tuning pins have gone loose it won't be worth changing them one by one, the piano should go to a proper workshop where professional restorers can take all the old pins out and carefully, evenly put new, thicker ones in. This opens the piano up to many other possible restoration jobs - the restorer now has access to the soundboard, and they might as well put new strings on while they're at it and do other repairs.
What materials are used to make pianos?
Since the late 19th century the frames of decent pianos have been one-piece of cast iron, to handle the 20-odd tons of tension from more than 200 high tension steel and copper-wound-steel strings. But even to this day perhaps the most important part of a piano –the soundboard is still crafted from various types of wood. The soundboard is responsible for amplifying the vibrations of the strings.