Posted on August 30th, 2016
TUNE PIANO, Over the last few years, I decided to run a few ultra-marathons (marathons run on trails in the forest). And I must go on record by saying that maintaining fitness is much easier than trying to get in shape to begin with. It was an arduous journey trying to get ready for my first event. But when our bodies are used to a certain routine over time, it becomes the new normal. In essence, we train in order to raise the bar for a new level of expectation.
You wouldn’t think it, but pianos can be in shape or out of shape. Pianos can go out of shape mechanically in the way that they play but can also get out of shape in the strings which determines intonation or pitch. Today I’d like to take a brief look at a bit more of a structural and mathematical concept of tuning and pitch. Before we do, we need to examine how and why pianos go out of tune and when you understand why they go out of tune, there is greater understanding with regards to getting them in shape and maintaining tuning stability.
Pictured above are the 3 types of strings on any piano. When you depress a key on the piano, it activates a hammer that strikes the strings. Depending on the zone (high or low), there are different types of strings. The largest bass notes are called mono-chords and only have one string per note. The double stringed notes are called bi-chord where the hammer strikes two notes simultaneously. And then for the top 2/3rds of the piano, a set of 3 strings (tri-chord) are struck simultaneously by one hammer. As seen on the chalkboard, there are 88 keys on the piano. When we separate the notes by type, we see that there are approximately 227 wires (which vary depending on the design of the piano). Multiply this total by the tension from each string (approximately 160lbs per string) and this gives the grand total of 36,320 pounds of string tension pulling on any piano! Note: the string tensions vary from maker to maker, model to model but also within one piano, the string tensions vary considerably. These are simply averages to grasp the concept of how much tension is pulling on the frame. Conservatively, the piano has 18 tons of tension (36,000 pounds) pulling simultaneously and that number can reach almost 30 tons of string tension for larger concert grands.
The wires then pull with an incredible force or tension. The cast iron frame (pictured in gold) together with the structural beams resist this tension. It’s a constant tug-of-war. The strings pull while the cast frame resists. Slight variations in this tension result in change of pitch and an out of tune piano. The question then is: what factors change the pitch of a piano?
There are 3 main elements which affect tuning stability:
1. New strings and windings
2. Tuning pin torque
3. Soundboard environmental changes
1. When it comes to change in tension, strings when installed at the factory will stretch. You wouldn’t think it but new strings have considerable stretch in the steel. The windings, knots and coils will also tighten and stabilize. This only applies to brand new pianos. There is a finite amount of stretch that will happen with new strings and within the first few tunings this will no longer be an issue. There is wisdom in tuning new pianos more frequently until the strings feel like they’ve settled.
2. The tuning pins are the adjustable “pegs” that technicians loosen or tighten with a tuning hammer. They are friction fit into the pinblock ~ usually a multi-laminated plank of wood. Interestingly, in England, they refer to the pinblock as the “wrest-plank”. The word “wrest” (similar to wrestling or wrench) denotes forcibly to pull or in this case, to turn the “wrest pins” (or tuning pins) inserted into the wrest-plank. Because the tuning pins are friction fit into the pinblock, they must have the correct amount of torque (the measurement of how tight fitting the pins are). Too tight and the pins becomes too difficult for a technician to adjust. Too loose and the tension of the string pulls on the pin resulting in loss of pitch. Tuning pin torque then is a significant factor that affects tuning stability.
3. Probably the greatest factor affecting pitch, however is the soundboard. The soundboard affects the tuning stability insofar as the strings cross over the bridge which is connected to the soundboard. In the picture you can see the strings cross over the bridge (adhered to the soundboard). Not only are the strings pulling end to end, but there is something called down-bearing where the strings are pushing down on this bridge. Since the soundboard is comprised of wood, it is subject to environmental conditions. Seasonally as the soundboard absorbs or dispels humidity, the soundboard will arc or flatten slightly resulting in pressure on the strings. Pianos can even go up in pitch if the arc puts considerable pressure on the strings.
All three of these factors contribute to slight deviation in pitch. When the steel strings are new, they stretch and become slack and need to be re-tuned. Tuning pins can move slightly and gradually turn out of position. The soundboard arcs more and then less depending on environmental conditions.
Making Sense of Cents
Pitch is not simply some arbitrary sound but rather, it has evolved into more concrete, measurable and universal terms. A440 is the global standard. A is the note (just above middle C) and 440 is the frequency or speed of that wave measured in Hertz (named after Heinrich Rudolf Hertz accredited for conclusively proving electro-magnetic frequency waves). When it comes to piano tuning, while you can measure Hertz, you can also define pitch in degrees called cents. As seen in the picture, each semi-tone has 100 degrees or cents. A full tone then has 200 cents. What this means is that there are 100 increments or degrees of pitch from one note to the next neighbouring note. So in discussing pitch, being a math and facts guy, I like to know how many cents the piano is out of tune. A piano that is wildly out of tune will be 40 cents flat (pianos usually go flat rather than sharp). So 40 out of 100 cents, if a semi-tone is 100 cents, that piano has fallen in pitch 40% of a semi-tone! Pianos that are tuned regularly might only go out 1-3 cents (out of a total 100). Often, pianos might go out of tune 5-15 cents in a year. What does this depend on? The 3 factors we looked at above. If your piano has gotten over “new string” settling when the piano is first purchased, then that leaves tuning pin torque and soundboard fluctuation as main factors determining pitch or intonation. The pinblock and soundboard will change with humidity. Pianos LOVE stable environments. Baseboard heaters, fireplaces, direct sunlight, drafts… even excessive fish tanks, plants all have bearing on humidity in the room which affects the soundboard which in turn affects the tuning. Change in ambient temperature (and subsequent humidity) within the house but also seasonally will make micro-changes in strings which also create difference in pitch.
Getting Your Piano in Shape
There’s a saying about piano tuning “You can’t tune a piano unless it’s in tune”. Paradoxical? It sounds that way unless you understand the sentiment. The farther out of shape your piano is, the more the tug-of-war will happen. The strings get pulled into shape, the piano tries to pull back to its known comfort zone. If a piano is 40 degrees out of pitch and you raise it to concert A440, guess what ~ your piano will not be at A440. Why? Because the tug-of-war is happening. The soundboard is adjusting to a new level of fitness. The subsequent outcome is that most pianos will pull back ~ sometimes up to 1/3 of the raise in pitch. So let’s take that example of 40 cents. One third of 40 is roughly 13. After tuning to A440 once, the piano will respond by possibly dipping down as much as 13 cents. Most technicians compensate and tune a little sharper knowing that this pull-back is going to happen. And so here’s the part that technicians CAN’T control. They can’t control the adjustment of the piano and the subsequent pull-back in 225 strings. Those strings will pull back at varying rates and thus, one tuning will never do the job getting a piano into shape that is vastly out of tune. The only way to do that is to tune again. You can really only tune a piano when it’s in tune ~ meaning that unless it’s close to pitch, you will never be able to get an exact stable tuning the first time. It is better to keep a piano consistently in tune than to let it drop significantly and try and pull it back into shape.
I’ve heard from many people over the years. “The piano doesn’t need tuning because I don’t play it that often”. While it can be true that a pianist who plays with incredible force can knock a piano out of tune, it is most likely the least contributing factor to making a piano go out of tune. Regardless of whether you touch a note on the piano or not, there is 18 tons of string tension pulling every day, 365 days per year. If a piano is prone to going out of pitch 4 cents per year, it might be out 8 cents in 2 years, 12 cents in 3 years and so forth. And pianos are funny that way. I’ve witnessed pianos that go out 12 cents in one year while others go out 2 cents in 8 years. But in closing, I will state 2 truths:
1. The farther out of shape the piano is, the harder it is to get it back into shape. And it may require more than one corrective tuning
2. Environmental stability is everything
Pianos are introverts. Hah… they like dark shady places where the sun doesn’t shine and no one rocks the environmental boat. The only problem is, we want pianos to be social and live in the center of our lives and enjoy the music with the sunshine. We need to maintain pianos if we want them to sound pure, beautiful and harmonious. I’m a firm believer in the fact that we are the recipients of the music from our pianos. If we train our ears with a consistently out of tune piano, that sound becomes the new normal. With an in tune piano, we communicate proper pitch every time we play. In closing, the message is simple: Regular maintenance is so much better for the piano than letting it drop in pitch for years at a time. Tune at least once per year and you will keep everything from sliding drastically out of alignment. Tune more than that if your ears demand it. And if you haven’t tuned for quite some time, do yourself a favour and get your piano tuned. Nothing is more satisfying than playing a piano that truly sings and really, pianos only sing when they are in tune and each note is in unison. Your piano may have gone down in pitch to such a degree that it might require more than one tune up session but as an old technician friend of mine used to tell me, “The difficult we can do. The impossible may take some time” ?
Posted on August 30th, 2016
I had the full intention of writing a blog on piano voicing and then suddenly realized that there are 3 completely valid meanings to piano voicing. The first meaning of voicing refers to chord voicing which denotes how you spread out the notes of a chord on the piano (quite often in the jazz idiom). The second meaning, as it refers to piano playing and pedagogy means making the melody line stand above the accompaniment. You voice the melody to be more audible than the rest of the notes you’re playing. The third definition however, refers to the technical aspect of manipulating the tone of the piano. It is this subject I’d like to delve into a little deeper.
When I was young I was slightly misguided in thinking that every piano brand had a signature sound. While there is truth in that statement, pianos can sound vastly different from model to model and can vary from even piano to piano. Why? At the core, the piano is comprised of natural products such as wood, felt, steel, leather and iron. All of these raw materials have anomalies and subsequently, no 2 pianos are the same. So while it is true that there are inherent qualities of tone related to a brand, the subtleties vary significantly from piano to piano. Voicing serves 2 purposes: one is to alter and change the global sound of a piano and two, to make a piano sound even.
What does it mean to have “even” tone? When I was 13, my piano teacher asked me to play a scale. “Play it like a string of pearls ~ matched in color and size. If you want to get louder, do so by tapering each note a little louder, then a little softer. Do everything gradually.” It was an idea that I could visualize where each pearl had its own quality and it was up to me as a performer to use some sense of skill to match one note on the piano to the neighbouring note. She taught me a lot about making simple technique musical. And when you play notes on the piano evenly in succession, it tricks our ears into thinking it’s monophonic (meaning “one sound” like the human voice).
At times, however, I’ll be playing what I believe to be consistently when all of a sudden, one note sounds different than the rest. Playing the note in isolation, it becomes apparent that this one note sounds sharper or “brassy”, bright or strident while the neighbouring notes sound warmer, mellower or darker. These are common words many people use to describe the tone of a piano. In short, the fix for the protruding note is called piano voicing. Piano voicing involves manipulating the instrument to achieve a different audible result. To create an even performance at the piano, it must be voiced so that each note sounds similar to its neighbours, making transitions in a musical line seamless. When I was in Hailun and Petrof factories last year, I took some time to watch factory workers whose jobs are solely voicing and tuning. It takes a trained ear and substantial skill to play notes quickly in succession and level the audible high spots which are strident and bring up the low notes to match the others.
So how does this process happen? How does one change the sound of a piano? To answer that, we need to think of what parts can be altered readily on a piano? Voicing predominantly involves altering the strike point of the hammer as it touches the strings. Yes, it could involve many other procedures but voicing is more commonly referred to as an immediate alteration to the wool hammers to produce a different tone. As to how this art of voicing happens, preparation precedes practice.
Pianos must first be in tune. How do you listen to the nuances of tone if the strings are not in unison? When you look inside a piano, 2/3rds of the notes have 3 strings per note. See our recent blog entitled How Often Should I Tune My Piano for a full description of the strings inside a piano. If there are 3 strings on a single note and they each are resonating at different frequencies, it’s like having 3 people talking at the same time. It’s impossible to hear the tonal quality of a note when all of the strings are not resounding in unison. So the first step leading to voicing is tuning. It is also during this time that most piano technicians make mental notes of the “worst offenders” which are anomalies across the keyboard. Because tuning takes well over an hour to get it in shape, familiarity with the piano also happens during this time. It takes time with a piano to find out what sounds it produces ~ what are its strengths and weaknesses and what areas need addressing more than others.
Levelling the playing field
Seating: At times, some notes will give off distortion. A trained technician will know that this is sometimes caused from the string not sitting flush up against termination points. Moving the string slightly can alter a note drastically.
Centering: Over time, some hammers shift from their strike position and don’t hit the all of the strings squarely. Adjusting the hammers to be striking in the center of the felt and at the same time is extremely important to consistent tone.
Travel refers to the movement of the hammer up towards the string. If the hammer is on an incorrect trajectory towards the string, it will hit the strings at more of an angle and also create odd tones or have one string strike before the other two. “Squaring” the hammers ensures they strike in the correct position at the same time.
Surface Preparation: If grooves in the hammers are significant, filing the felt of the hammers should be done to regain proper surface contact.
Action Corrections: Sometimes one note will be misbehaving mechanically and render it powerless. In such cases, it tricks our ears into thinking it has a different tone when in fact, there’s a mechanical problem. There are many issues that can arise in a piano that lead us to believe individual notes need voicing when in fact they require mechanical fixes or adjustments.
With the aforementioned areas addressed, voicing can now commence. Please note: these are piano BASICS. Pianos are much more involved but for the purpose of describing piano voicing, these are the baselines which all pianos must adhere to. These are the practical fundamentals of most household instruments and not concert level pianos which can sometimes take days to tweak.
So let me ask, what kind of tone do you wish to have coming from your piano? Beauty, after all, is in the eye of the beholder. Some wish for a power piano – strong and bright. Others want soft and felty. Personally, I look for versatility in a piano. I prefer pianos to be intimate and warm at softer dynamic levels and have a crossover where they can shift into more strident sounds when playing with force. Pianos that are icy cold or brittle at softer volumes I find somehow less satisfying and difficult to express emotionally. Conversely, playing powerful music with a dull thud also feels like it is somehow lacking.
Let’s be clear, however that piano voicing has limitations. I’ve often said that 50% of the tone of a piano is inherent to the instrument. It’s the wood ~ the soundboard, the bridges, it’s the design ~ the scale, the placement and thickness of the soundboard, the amount of ribs, backposts, rim construction etc., it’s the action ~ how it translates our musical intention into sound – all of these elements make up the piano. These I would mainly consider non-negotiable. Yes you can start down the path of reconstructing parts but this is more major surgery. The other 50% can be altered somewhat depending on the quality of the piano and the results vary drastically. Piano hammers also have a shelf life as well. Really old and “dead” sounding hammers fibers, ones that are really grooved, hardened or lifeless sounding need replacement.
Most pianos with time and playing become more brittle and harsh. The majority of the requests for voicing involve making pianos softer with fuller body. When I was young, I sought the brassy power piano. As I age, I look for tonal color more akin to “autumn leaves” ~ colourful, warm and beautiful. We get used to the piano we play and don’t consider that alterations could make the experience more enjoyable. With harsher tones, piano hammers can be “needled” in various locations to achieve those results. A needling tool simply has needles that get inserted into the piano hammer. Since piano hammers consist of felt stretched and glued around a wooden hammer molding, the insertion of the needle “fluffs” hammer felt, making it not so compacted. In other areas of the hammer head, the needle acts to give greater body or sustain. Most piano technicians know how to needle to create the desired effect.
Solutions for both hardening and softening also exist. A hardener coats the hammer and creates more brilliance in tone. Softeners penetrate and relax fibers and create softer sounds. While there are those who disagree with putting anything on the hammers, I believe that there is a place for more drastic alterations of hammers that have desirable end results. The danger is that solutions can be added to a hammer but cannot be extracted. I’ve actually played pianos rendered unplayable due to excessive chemical applications. The recourse really is only to change the hammers. But I’ve also played many pianos that have been strategically voiced with solutions for incredible results. The word here is caution and work with a piano technician you trust. Ideally, I like the felt of the hammer to speak. If you’re looking for a certain sound, sometimes changing the hammer is a better way than to try and artificially transform a piano into something it wasn’t intended to be.
Pianos are dynamic in nature. They are constantly changing. Voicing is not a do-once application but rather a process with time and maintenance. It involves keeping the piano at its best throughout its life-span. Have you lost the love of your piano? Sometimes pianos simply need to be voiced to bring it back to more of the sound when you first acquired it. You’ll be amazed at the results. Piano maintenance is so much more than tuning. Once you realize the possibilities, you’ll be amazed at how musical and beautiful your piano can be.