Posts tagged felt
There has never been said any words in the piano industry that are more divisive than “But does it have a middle pedal?” Why are these words divisive? Because the middle pedal on the piano is the least used and yet most focused on in the piano industry. I’ve often told the story about one of the greatest jazz pianists in my city, when he was just signing the papers to purchase a beautiful grand piano, he stopped and turned to me and said, “Glen, I’ve just got to ask… What does the middle pedal do? I get asked because I’m viewed as the professional and yet I don’t even know and I’m too embarrassed to ask! Can you please tell me?” We both had a bit of a laugh because he’s an incredible professional musician who has existed for decades without even knowing what it does. After technically showing him he then said “When would anyone use that?” Precisely my point.
The middle pedal on the piano, if you would break it down into frequency of use might possibly be 98% for the right pedal, 1.9% for the left pedal and maybe (if you’re lucky) 0.01% for the middle pedal. The right pedal, the sustain (also known as the damper pedal) is used with every musician and every player because it lifts the felt dampers and sustains the notes and keeps the strings resonating even after we have lifted our fingers. In essence it “fills in” the sound. The left pedal, the “una corda” pedal changes the dynamic (volume) level of the piano and/or the timbre of the tone – making it the soft pedal. But the middle pedal… ahhh yes the infamous middle pedal has been known to have 5 different usages.
In this article, we’ll take a look at the advantages of the middle pedal and why it’s not the best decision to judge a piano based on this non-standard device.
Pianos equipped with the sostenuto function are what I would call “selective sustain”. While the right pedal sustains all the notes, the sostenuto, in essence holds down selective notes you wish to sustain. I love how this chap in the U.K. both demonstrates and performs on the piano utilizing the sostenuto pedal (video to the right). He beautifully shows both the function and form of the sostenuto.
As you could see in the sostenuto video, most of the time, the sostenuto pedal is used to sustain the bass notes. So why not make a pedal that just sustains the bottom notes? Some manufacturers decided instead of offering a sostenuto pedal (which is more labour intensive in manufacturing) they would offer a type of split sustain. The middle pedal would then act like the a sustain pedal for just the bass notes.
Practice – Mute – Celeste
Herein lies the big departure for the middle pedal as it has absolutely nothing to do with sustain at all and yet can be found in most modern upright pianos today. It is called the practice pedal, the practice mute or the “celeste”. The purpose on this middle pedal is to reduce the volume of the piano by sandwiching a thin layer of felt between the hammers and the strings. Take a look at this 10 second video and you’ll get the idea. This is neither a sostenuto nor a bass damper. It doesn’t function like the above pedals. It simply is meant to mute the entire piano (much more than the soft pedal).
With modern manufacturing, the middle pedal has also been used as the silent pedal while simultaneously engaging an electronic device to allow you to listen to your piano with headphones. Known as “silent” or quiet option, the middle pedal blocks the hammer from striking the strings. What you will hear then is a slight knocking from the hammer shanks (the “handle” of the hammer) against the silencing rail. Underneath each of the keys are infrared sensors that determine what notes are being played and transmit signals to an electronic device which makes the digital piano sound come out of headphones. For night time playing or extreme privacy, these pianos are brilliant.
Novelty or Nothing?
I have to admit (and am thankful to say this) but I haven’t seen a “novelty” brass tack rail for many years. Similar to the practice mute pedal, the novelty rail lowers a series of brass tacks in between the hammers and the strings and makes the piano sound like a honky-tonk piano. Alternatively, I’ve also seen pianos that are connected to… nothing. Nothing? Yes nothing. Why would a piano have a middle pedal connected to nothing? The answer is simply that customers wanted a third pedal. Cosmetically, it may have satisfied some consumers but opening up the piano I have on more than one occasion seen pedals with no function whatsoever. They’re pretty rare though, but provide a bit of a laugh when you’re asked to fix the middle pedal.
Today’s manufacturing world mainly has evolved to having a standard sostenuto pedal on grand pianos and a practice mute pedal on upright pianos. Regardless, it’s probably not the best choice to base a piano decision on the middle pedal. As a friend of mine once said “it’s like buying a car based on the radio antenna”… referring to the obscurity of use.
History of the Sostenuto Pedal
According to Fred Sturm in his paper “The Invention of the Sostenuto Pedal”, he writes that pianos used to have many pedals (upwards of 7!) during the early 1800’s when there was more experimentation around the piano. The sostenuto pedal was patented in France by the Boisselot brothers in 1843-1844. “Sons soutenus” simply translated means “sounds sustained”. After another piano maker, Montal exhibited pianos with this pedal function in the mid 1800’s World Expositions, this invention was given more exposure. Fast forward to 1874, a patent was presented in the U.S.A. by Mr. Waldo Hanchett. In his diary (shown above), William Steinway commented after viewing this invention that it was splendid. After some legal and patent disputes, Steinway re-designed the pedal and forwarded a patent in 1875 for the sostenuto mechanism as we know it today. If you have the time, check out Fred Sturm’s paper – a fascinating read.
Practical Application of the Sostenuto Pedal
As previously mentioned, the main idea is usually to sustain lower notes while changing chords in the upper register. When you depress lower keys and then press the sostenuto pedal, they create a foundation of sound from which you can then superimpose other chords on top of without affecting the selected lower notes. But what happens if you don’t have a sostenuto pedal? What if you have an upright piano with a practice mute? The work around is that you can get a similar effect by half pedalling the sustain (right pedal). Since the lower notes vibrate with greater energy than higher notes, if you half pedal – meaning that after you depress the sustain pedal, you only come up until the dampers slightly touch – you can still keep the energy of the bass strings and clear the top notes. It’s not a true sostenuto but it accomplishes a similar effect for the rare times that it is needed.
To conclude, I’ll leave you with my all-time favourite quote about the middle pedal which comes from the comedian/piano performer Victor Borge who said “You know, some people have asked me why there are three pedals on these grand pianos..Well, the pedal in the middle is there to separate the two other pedals…which might be bad news for people with three feet.”
A few months ago we examined the mechanical and musical basics of the damper pedal. This month we’re going to look at how the una corda, also known as the soft pedal, works.
I was speaking with an older gentleman recently who used to be a typesetter for a newspaper, meaning that he would manually place letters in rows each day for the daily newspaper (pre-computer and pre-typewriter). Each of the letters in the alphabet was grouped together and were called “sorts”.
As the day progressed, depending on what the typesetting would require, you might run out of a certain letter, like a letter E or letter A, for example. And so if you were “out of sorts”, meaning that you had run out of that particular letter, you would go into the storage room of letters and get more sorts, another container of that character. The insinuation is that if you’re “out of sorts”, all production stops until you remove yourself from your work, restock and regroup and then continue on. I love these kinds of stories that reveal the story behind the phrase.
The soft pedal on the piano also has not-so-quaint a story but interesting nonetheless. Cristofori, credited with the invention of the earliest pianos in the 1700’s also installed the “una corda” pedal into his pianos. Being Italian, the phrase “una corda” can be translated “one string”. How does “one string” translate into a pedal we also know as the soft pedal? We’ll look at that in just a moment but first, let’s take a look at the structure of the left pedal on the piano called the soft pedal or una corda.
First of all, grand pianos and upright pianos have very different functioning soft pedals. The grand piano shifts all of the keys from left to right slightly. As you can see in the top picture, the keys move away from the rim at the left. This, in turn makes the hammers off center from the strings they are striking. What’s happening below the surface is that the soft pedal (the left pedal on any piano) is connected to a rod which eventually joins to a lever that swivels. This swivel piece sits under the entire keyboard frame and moves all of the keys from left to right. Why shift all of the keys? On the majority of the keys on the piano there are 3 strings. When you shift the keys using the soft pedal, the piano hammers strike only 2 strings (pictured in the second frame) instead of 3 and thus, the piano becomes softer. But what is also simultaneously happening is that the hammers, being shifted out of their usual strike pattern, are also hitting on fresh felt. When the hammers are aligned to strike at the normal position, they will, over time, have small grooves in the felt. When the soft pedal is engaged, shifting from left to right, the hammer is no longer striking those same grooves. The effect then is that the tone is usually quieter but also softer and warmer in timbre.
Mechanically, upright pianos operate very differently and the soft pedal on any upright is not really any kind of “una corda” since it does not shift the keys. Rather, it pushes the hammers on a single rail forward towards the strings (pictured below). How do closer hammers make the piano softer? It simply gives you a bit more control bridging the smaller gap between the hammers and strings. Hammers on an upright piano travel the full distance to the strings under normal conditions. When they are moved closer, the idea is that with less distance to travel, it will be easier to control. Try this as an example: if you wanted to clap your hands loudly, it is our natural inclination to first separate our hands a fair distance to make the impact greater.
What happens if you move your hands only a foot apart and aren’t allowed to move back before you clap? The result is that the lower distance only allows for lower impact and thus lower volume. Upright pianos work the same way. When the pedal is depressed, a rod simply engages a rail that moves all of the hammers closer to the strings in hopes of limiting the loud playing and making a closer strike distance. The result is quite often negligible and the tone, unaffected compared to a grand piano moving the hammers onto fresh felt.
So where does the term “una corda” come from? Back in the day of Cristofori (early 1700’s), each note on this primitive piano had only 2 strings. Using the “una corda” shifted the keys so that they would only strike 1 string. How different the piano would sound if you would only strike one string at a time. It would sound not only quieter but also thinner. Our ears are so accustomed to hearing 3 strings simultaneously, it would actually be odd to hear a single string resonate at a time. It would be more akin to a guitar. Over the years, however, the term “una corda” has become an anachronism. Although it’s outdated, the term implies quiet and more intimate playing. I guess we could start a quiet revolution and call it Due Corde (2 strings)… but then again, the initials DC are already taken meaning Da Cappo. Piano nerd humour. Hahaa.
As an aside, if you ever get a chance to visit the keyboard museum in Vienna, Austria (Kunsthistorisches Museum Wien), the instruments dating from the 1700’s are completely fascinating and being able to see the historical developments up close is incredible. I highly recommend it!
The teacher has said “It’s time you start looking for a real piano and move up from a keyboard. You’ve outgrown this one”. Really? How does that happen? Just 2 years ago you bought this brand new 88 key weighted digital piano and now you’re being told that it will not suffice. They both have the same amount of keys and it has the same touch as a piano. Why do we need to upgrade? In order to answer that question, we need to look at the differences between acoustic piano (traditional piano with strings and hammers) and digital piano (electronic keyboard that you plug into the wall). The two main areas that substantially divide these two types of pianos are dynamic touch and dynamic tone.
The concept of touch for any keyboard is fairly straightforward: they all have black and white keys. You push one down, it makes sound. But in reality, the constructs of touch are much more complicated. Remember going to the playground when you were a kid? The see-saw was one of my favourites (especially when your brother or sister is on the other end and you decide at last moment to let it crash to the ground seeing them slightly propel off the end in mid air). Anyway, the idea of balance is realized fairly quickly. We all experimented by moving closer and farther from the middle. It took substantial weight to push down the see-saw if you were really close to the center. Piano keys are exactly like that. When it comes to upgrading from digital piano to acoustic, one of the most significant changes is a better balance point. What do I mean by that? When you play the piano, the ideal is to have consistency moving from one note to another. But you also want to achieve consistency from the front of the key to the back. Take a look at the diagram with the two different pressure points marked in red. As the demands for piano proficiency increase, you end up using the entire key surface and not just the fronts. When you look at the cutaway of both digital and acoustic pianos (on the next diagram), you will see that digital pianos have balance points that are too close to the keyboard. It’s like the see-saw principle: the closer you move to the center, the more difficult it is to depress a key. Here’s a test to try: depress a key on a digital piano similar to the red marks on the diagram. Take note to the variance in touch. Digital pianos, by nature of the balance point placement usually have significant touch discrepancy. With acoustic pianos, the balance point distance is substantially further. This creates a more even touch weight from front to back of the key. One sign of a great piano is low variation between the front and back of the keyboard.
Another significant distinction between acoustic and digital is the idea of dynamic touch weight. Have you ever gone camping? Good, because it’ll help with this next analogy. Chopping wood requires rotational inertia. The axe handle pivots in your hand while the weight at the end gathers momentum and chops the wood. Due to the multiplying effect of the rotation of the axe head, the power increases substantially. Any seasoned pianist will be able to tell you that acoustic pianos somehow feel different than any electronic or digital piano. The reason for this is due to this rotational inertia of the piano hammer causing dynamic touch. Take a look at the side cutaway of the upright piano. Labelled is the hammer which rotates towards the string. This rotational inertia, similar to a hammer or an axe – gives a very different sensation than the static weight of a digital piano. A digital piano simply raises or lowers lead weight up and down. It doesn’t have a multiplied force when played louder and subsequently, there is no dynamic force on a digital piano.
There are many other subtle differences that we could consider regarding touch, but the last one we’ll look at is spring assists. Ever so slight and yet perceptible is the idea of resistance in part by springs in the action. In an upright piano, for example, the pivot point of the hammer we just spoke of not only has rotational inertia but it’s also spring loaded. The spring resists the hammer and at low pressure, low volume, you can feel the spring engaged. As the hammer moves closer to the piano strings, the tension of the spring also increases, causing more pressure to return the hammer to reset.
So why upgrade? Longer keys mean better balance from front to back of the piano keys. The rotational inertia gives dynamic touch changing the feel as you play soft to loud. And finally, the spring loaded joints aid the reset. All of these work collectively to define the touch of a piano. When you compare that to a digital piano where the touch weight is simply raising or lowering a lead weight on a see-saw, the difference is significant. In addition to these touch elements, traditional pianos also have adjustable parts to refine the touch components as well.
Final considerations regarding touch: dexterity and injury. After nearly 30 years of teaching, I could tell as soon as I heard a student who had been practicing on a digital piano. How? They have not developed anywhere near the right amount of finger dexterity. You can “hear” that their technique is weak. Dynamic touch brings about correct dexterity. You can especially hear it on quick staccato passages. But the more important consideration is injury. Extended practice time on digital pianos have the propensity towards injury. I’m not a kinesiologist but I think it has something to do with repetitive loud playing on the digital piano. I believe that the force is somehow not absorbed the same way because digital pianos do not have dynamic key weight. When you come crashing down on the keys, if the static weight doesn’t change, the next absorption point is the hands and arms. The dynamic nature of the acoustic piano changes the resistance when you play and for whatever reason, I find it more forgiving.
When it comes to upgrading from a digital piano to an acoustic piano, there are also 2 sound concepts to be mindful of: The first is the continuous flow of sound which we commonly refer to as analog. The second is dynamic timbre referring to how the sound quality changes with dynamics and volume.
First, let’s look at the comparison between acoustic sound and digital sound. The acoustic piano creates sound by a hammer striking a string. The subsequent vibration is amplified by the soundboard into audible tones. How do digital pianos make sound? Digital pianos don’t actually create sound. They simply play back a digital recording of a real piano. But digital sound and live string resonance are different. Digital sound is made up of many frames per second to give the illusion of continuous sound. Natural vibration of a string is a continuous waveform that we perceive differently. I remember the first time I used Skype to speak with my parents a thousand miles away. My aging father found the technology almost baffling. It was great to see their faces and connect but is it the same as being there in person? No of course not. Both methods communicate effectively but the live version brings about a closer heart connection. A picture of a garden or being in the garden, a filmed version of a Shakespearean play or experiencing live theatre, hearing a recorded version of your favourite artist or seeing them live in concert ~ live is simply more than the digital representation. And yes I’m well aware of the fact that there are incredible creative moments that can only be achieved in the digital realm. It’s not that it lacks expression as its own form. My point is that digital piano will always and only be a facsimile of a real piano. And as it relates to acoustic analog continuous sound waves versus a digital recording of a piano transmitted through speakers, natural sound will always be the better choice.
The second concept of sound is the idea of dynamic timbre. Just as acoustic piano touch is dynamic and changes with volume, so too piano tone or timbre changes character with volume. As the hammer strikes the string at soft to loud volume levels, the piano hammer felt is compressed differently. The subsequent tones often go from felty and warm to strident and bright. Depending on volume, other sympathetic tones of the piano also ring. An acoustic piano is not a matter of simply raising or lowering volume but rather, the piano tone changes color with dynamic touch.
Crayola crayons – remember the new boxes you would get at the beginning of the school year? Digital pianos are a little like that small box of 8 colors. In the recordings of digital pianos (called samples) manufacturers have attempted to capture these dynamic timbres. What this means is that when you play from soft to loud on a digital piano, it transitions through the various colors of samples. But when it comes to upgrading, advanced students need to move beyond the 8 Crayola colors. Advanced playing requires shading, nuances and a wider color palette. You simply cannot hand a student a box of crayons and say “Paint me a masterpiece”. It’s physically not possible. You think I’m being facetious but most manufacturers use less than 4 “colors” per note. Conversely, traditional pianos have an infinite number of colors. And that’s just in one note! When you strike more notes simultaneously, the color possibilities and frequencies increase exponentially. Quite often I think back to the famous pianist Glenn Gould. I read that his parents had to lock the piano after 14 hours a day of playing when he was a child. Obviously he was genius and radical in his approach to piano playing but in reading about his life, it’s apparent that he was completely smitten by the tone of the piano. I fear that we don’t give students the capacity to LOVE the piano for its sound. I wonder if we as parents do a disservice to children by giving them the incorrect tools to begin with. There’s this common school of thought “Let’s get a keyboard and if they stick with it, we’ll get them a real piano”. Do children learning the piano ever fall in love with the tone of a keyboard? Have we lost the connection to analog – this continuous vibration of the strings? Does it resonate with us the same way? Have we given them a handful of colours and limit the pure enjoyment of limitless expression?
I believe these are the thoughts and intentions behind teachers wanting more for their students. When they speak to parents about upgrading, it’s not about some high-brow approach to narrow minded Classical performance. It’s the desire to connect with a more fundamental, more organic way of expression in music – one that is beautiful and lovely. So the next time the teacher encourages you to look at a traditional piano, they’re really saying ‘Let’s go deeper, let’s create music, and let’s experiment with touch, with tone and experience music to its fullest extent.”
Today’s topic is piano dampers. When your finger depresses a key on the piano, the string vibrates allowing us to hear the wonderful tone of the piano. But what happens when we lift that same key? The key returns to its upright position and the tone stops resonating. Why? The piano mechanism called the dampers simply press felt blocks on the vibrating strings to terminate the singing tone.
To understand a bit more about dampers, we brought in Marc Venet from world renowned felt maker Laoureux in France!
But before we delve into piano dampers, we need to take a brief look at the piano strings. On any modern piano there are usually 3 sets of strings: tri-chord, bi-chord and mono-chord. The prefixes of tri- bi- and mono- give away the fact that there are notes on the piano that contain 3, 2 and 1 string. This is significant because as we’ll soon hear, damping 3 strings at a time is very different than damping 1 string. The largest strings on the piano are the bass strings. They are copper-wound strings and produce the lowest notes of the piano where you can actually see the vibration of the string. Conversly, as you move higher in the piano, the frequency of the waveform gets faster and we can’t see the vibration. Piano strings can be called “sinusoidal” from where we get the root “sine” wave. The purpose of the damper then is to stop the wave and subsequently, the sound. The damping techniques and felt types are really different to mute different thicknesses of strings and their varying degrees of energy.
Without further adieu, and knowing a bit more of the background of dampers, let’s talk to Marc Venet from Laoureux.
Glen Barkman: The history of Laoureux, it’s been going a long time and is one of the largest piano felt makers in the world. Can you tell us a brief history of the company and how you got involved?
Marc Venet: Laoureux was founded in 1923 by Mr. Laoureux and after 3 generations of Laoureux’ leading the company until 1976, it wasn’t doing well financially. It was purchased by SCAPA group who bought the company in order to build a conglomerate in European felt business (Naish felts, Royal Georges felt, Laoureux, etc.)
My father was hired at this time in order to restore the profitability of the company Laoureux, which he succeeded to do above their expectations and quite possibly be the reason why Laoureux is now the only felt maker from this group that survived and producing today. The choice he made was to concentrate on high quality, hand made felts and avoid mass market felts like those found in the automotive industry, for example, which have bigger profits, yes but also involve big risks and large turnovers. It was a good choice. My father finally bought the company in 1988 and I joined the company in 1998.
GB: There are 3 types of strings and yet 4 types of dampers (mono,bi,tri and treble), can you tell us how each of those work?
MV: The shape and the types of dampers depend on the string they are supposed to damp.
A – The “Mono” or “One string” looks like a square with a V shape inside in order to envelop the large string on bass section of the piano.
B – The “Bi” or the “Two strings” looks like a V shape in order to get inside the space between the two strings on the tenor section of the piano.
C – The “Tri” or “Tri strings” looks the same as the “two strings” wedge shape but contains a split in the middle to act as a double wedge. These are for the lowest plain wire strings.
D – the “Flat damper” looks like a cushion of low density felt and are used for the highest notes on the piano.
For all dampers the target is to damp the sound, that means that they are in charge of absorbing the vibrations of the strings. Those vibrations are in fact frequencies like sinusoid signals (pictured above). The bass notes have low frequencies which mean long and spaced sinusoidal waves, and on the contrary, the treble or high notes have high frequencies which mean shorts but repeated sinusoidal waves.
Of course, for playing the piano, it is interesting to have more or less the same time to dampen the sounds when you release the keys, wherever you play on the keyboard (bass, tenor, or treble) and yet the frequencies and subsequent energies are quite different. For achieving that, we use different dampers with different properties adapted for the frequency of the sound. On the treble section, frequencies increase drastically when you play more to the extreme treble section. So for this section, even if there are 3 strings for each note, we have to change the method of damping from the double wedge to the flat block dampers.
GB: Is there a certain density of felt that is ideal for piano dampers?
MV: Yes of course there are optimal densities for dampers. And there are also certain densities depending on the placement inside the piano (density for bass and for treble felt are different). Ideally the density should be as low as possible. You could find on the market bass dampers with densities from 0.23 up to 0.35 and for treble dampers ranging from 0.14 up to 0.25. Physically, density is weight over volume (D = W/V). For the felt manufacturer the challenge is to make low density felt because it has superior damping properties however it is much, much more difficult to produce. In order to be able to cut them with a high degree of precision (1/10 a millimetre) the felt should be perfectly consistent otherwise it is impossible to cut. The challenge is also for piano technicians, it is much easier to work with “hard” dampers when you do not have the correct know-how and experience. A soft felt is difficult to make on several levels: First, achieving the felting process for low density is very difficult, because if you are under the good “felting point” (felting being the intertwining of fibres), the middle of the felt will remain as only wool if it is not felted. And if you are over the optimal felting point you are too hard on the surfaces and soft in the center and thus, the felt is not consistent.
The job consists of making felt the same from top to bottom. This is not easy. It takes much more time, involving more hands-on processes and also involves a lot of waste. That is why it is more expensive than denser felt. Ironically, you pay more even if there is less wool inside because it is much softer but contains greater damping properties.
GB: In the cullinary world, it’s kind of like baking the cake right? Too hot and you burn the outside, too cold an oven and the center doesn’t get cooked. Interesting. Speaking of damping properties, what makes for great dampers? And can you take us through the manufacturing process a little?
MV: Wool is the first and natural technical fiber with a “form memory”. The felt pressed against the strings absorbs string vibration. If you leave the felt released, the impression will erase. This is what makes great dampers. The softer the felt, the better the form memory. Making great felt requires technical know-how but also great raw materials. Normally felt is graded by 2 criteria: the quality of the wool used and the density. We buy the wool taking into consideration the length of the fibers (told in millimetres), diameter of the fibers (told in microns), and ability to felt more or less (the curving of the fibers). Of course the thinner and the longest fibers are much more expensive than the shortest and the biggest fibers.
A – Wool opening and Blending: we make a blend of wool with different single lots in order to have something always the same. With blended wine for example, you assemble different qualities with more or less the same proportions to create consistency. If we were using only one type of wool for each production, we would have different results from one production run to another and so good blending allows consistency in production.
B – Carding: the blend goes into the carding lines in order to create wool layers. With our machines we can adjust the weight by square meters of the layers, and also the fiber direction (crossed or not).
C – Composition: It is a hand made process consisting of assembling and cutting several wool layers depending on the final result we want to achieve. In short, we know the final dimension and density we want. We will use the right weight of wool at the right dimension taking in consideration the shrinking coefficient we will apply.
D – Felting: The transformation between wool to textile. It is a natural process (no chemicals involved) where the fibers are matted together via friction.
E – Fulling: Once we transformed the wool layers to felt, we have to shrink it to it’s final dimension in order to give it it’s right density. This is again a hand-made process, one piece at a time. Dimensions of the felt should be controlled because we need to keep consistency in the shrinking. The right density is obtained when the felt is at the right dimension, not before, not after.
F – Drying. The previous process of felting and fulling require moisture and so the felt must be dried.
G – Pressing: Here we calibrate the thickness of the felt, for example 10.2 mm thick. We use hot presses to achieve this.
H – Finishing: Depending the product we make it goes to the dedicated workshop in order to be cut or assembled to its finished purpose.
GB: Aside from piano felt, what other applications do you make felt for?
MV: There are many many different applications for felt. Felt is used for its natural properties of absorbing, transferring and sealing. Some industrial fields using felts: writing instruments, railway, automotive, nuclear, tools, bakery, design and of course, piano making.
Glen Barkman: Wow that was a fantastic glimpse inside the world of felt making by Laoureux. They are located in Normandy, France and operate in 7,000 m2 facility (about 75,000 ft2 factory). A special thanks to Marc for his expertise and continued dedication in providing the world with quality felt.
“World War II – July, 1944 ~ 71 years ago almost to the day, 85% of the Renner factory was destroyed. Wilhelm Megenhardt, then 70 years of age simply replied ‘We’ll just build it up again’. He continued working until 85 years of age after Renner had become a leading producer of piano parts. He was my grandfather.”
Glen Barkman: It was a delight and privilege to sit with Clemens von Arnim (pictured left) and ask him about his connection to Renner. I had no idea that it was his grandfather, Megenhardt who partnered with Renner in the early days of this business and eventually became sole owner.
Established in 1882, Louis Renner opened a small workshop in Stuttgart. Operating with 25-40 workers, he built a successful business around making piano parts (also known as action parts). Twenty years later, as he began to struggle with his health, his son Oskar Renner assumed position as technical head of production. Shortly thereafter in 1906, in partnership with Wilhelm Megenhardt, they opened a modern factory manufacturing action parts as well as piano hammerheads.
Why is Renner important? Aren’t there other makers of action parts? The answer is yes, there are many makers of parts, it’s just that none of them have the reputation of Renner. Throughout the pages of Piano Price Point you’ll come across this phrase “Renner option available” or “Renner hammers”. When I’ve asked consumers, pianists and even aficionados about Renner, I usually hear a similar response: “I’ve heard of Renner but don’t really know what it’s all about.”
In short, Renner builds the finest action parts money can buy. The most prestigious, exotic piano makers in the world use Renner parts. Take a look at the chart below of piano companies that Renner supplies to. If you know some of the names on this list you’ll know that they produce the finest instruments in the world. And so why use parts from a company like Renner? Listen to the words of Clemens von Arnim to hear more:
Clemins von Arnim: Our philosophy is based on 4 words: Quality, Reliability, Precision and Durability. How we accomplish that comes from the original mandate set out by Louis Renner himself. A standard grand action has more than 4000 parts. He set out to meet the demand for consistent quality. When you play a piano, all 88 notes need to respond precisely in the same manner and each of those keys has a minimum of 45 action parts. How does one manage to meet the stringent criteria for the highest level of quality? The answer is multi-faceted but let me start off by telling you a simple example that is decades old in the Renner factory about planing wood – one that set Renner apart. You see, to make piano parts, you must plane or cut wood to specific shapes and sizes. Cutting with the grain of wood is easy. Cutting across the grain at 90 degrees requires the correct tools. If the machinery is not extremely rigid, the edges of the cutting machine will ‘jitter’ against the wood and you will end up with course or substandard parts. In my grandfather’s era, at the Renner factory they over-built, over-constructed these planing machines to almost 2 ½ times the specifications so that cutting the smallest pieces would be accurate and smooth.
CvA: That original machine existed in our factory for decades. And it got replaced not because we had outgrown its usefulness, but rather automation in manufacturing prevailed. But it was this commitment to quality – to engineer and have machines that could produce the finest parts of the highest quality that set Renner apart more than a century ago.
GB:That story sounds like one where they call the inventor crazy until they see the end result. Tell me about your parts and how they are made.
CvA: Our parts are made of hornbeam wood. Trees need to be cut between November and March when growth is slow and not so wet. Boards are then cut and air dried for one full year. This is very important because if you dry it too quickly, it has too much tension. It is then kiln dried until it reaches uniformity at around 8-9% humidity. After that, boards are sorted by our specialist for usage (see diagram). Vertical grain is used for hammer shanks while horizontal and diagonal grain wood is used for other action parts. In the end, 60% of our production lumber we deem as firewood and only use about 40% due to our stringent quality controls.”
GB: How has Renner managed to stay on top of the industry for so many years?
CvA: Aside from the commitment to quality, Renner has over 100 years of technical experience. There is a balance between modern automation and know-how when it comes to natural products. You cannot simply rely on machinery to have intuition regarding natural materials of wood and felt. And so 50% of our processes are automated and 50% involve hand-made personal touch. We have two facilities – one at Gärtringen (near Stuttgart) and one at Meuselwitz (near Leipzig). What has kept Renner going is that we can deliver and have met the demand without comprimise. Renner is the largest purely piano action manufacturer in the world. Over 3 million piano actions have left our production facilities.
GB: Somebody please do the math… conservatively 4,000 piano parts per action x 3 million actions… anyone? 12 BILLION parts. I think it’s safe to say that Renner can deliver.
CvA: In 1952, we expanded yet again to offer not only parts for new fabrication but also for repair and rebuilding. We manufacture over 1000 types of piano hammer heads. One of the reasons Renner continues to exist is the fact that we can supply not only volume but also make hammers with custom requirements. Clients tell us how firm the felt should be, how much felt is required around the wood and what sound they’re trying to achieve. We can troubleshoot and even offer suggestions to those wanting to customize action parts. Now, in the age of computer assisted design, the diversity is even greater. Over the years we have gained so much knowledge in working with wood and fibres of felt that we can control variances to very small percentages. Our tolerances at Renner are less than 1/10th of 1 millimetre which is sporty if you know what it’s like to work with natural products of wood and felt.
GB: This was one of those moments that made me smile .. “sporty” (I thought to myself) was the perfect word that describes the healthy pride in accomplishment and ownership but also denotes great satisfaction.
The Renner Advantage
CvA: Because of such tight tolerances in product manufacturing, our long standing knowledge base, combined with our hands-on technical team, we are capable of not only making beautifully crafted actions for today but also ones that will remain consistent for long periods of time. Our actions need little adjustment.
GB: If you’ve ever sat down at a piano with a Renner action, you’ll know that the touch and feel is superb. They play as smooth as silk and feel as rich as chocolate.
Many thanks to Clemens von Arnim. It was fantastic to meet face to face and to learn about Renner and the history of not only your family but the heritage that Renner has made. Renner has changed the world in creating music with the most prominent piano makers in history. The greatest concert pianists have played on piano actions created by Renner.
Renner has its own Academy for training purposes on piano actions. Below are some links to Renner around the world. Enjoy!
Renner Germany ~ Renner USA ~ Renner Academy
Behind the scenes in the piano business it’s a very small world. You won’t last but 10 minutes before you hear something about Abel hammers. Hammer heads – the felt that strikes the strings on a piano are in my mind the most critical foundation of tone. Abel is world reknown specializing in hammer manufacturing. It was my pleasure to meet Norbert Abel last month and have him shed some light on the piano hammer making proccess. Every time I interview someone I learn something new about the piano trade. Although I’ve been in the business for just over 20 years, I only now have heard 2 words which were unknown to me before this interview: Lanolin and Biofelt. Read on to hear the words of Norbert Abel. And by the way… Abel makes about 50,000 sets of hammers per year… multiply by 88 keys on a piano that equals 4.4 MILLION hammers annually. They are arguably one of the greatest authorities on hammer making in the world.
Glen Barkman: The History of Abel – How did you come into this business?
Norbert Abel: My father, Helmut Abel started his own hammer production business in the year 1982 after he had worked for another German manufacturer making piano hammers and action parts for 23 years. His goal was to produce hammers in the ‘old style’ which meant custom making hammers for each manufacturer using high quality materials and advanced techniques.
All pianos are different and have individual requirements and so with this custom approach, he convinced many of the piano makers and technicians with the Abel quality and philosophy; making hammers for many brands to individual specifications.
From the beginning I have been involved in the business side and have seen the continuous growth and development of production. In 1988, my brother Frank started into the business and has taken over production. The third generation, my son Alexander is now learning step by step the difficult procedure of hammer making. Since 1993 the Abel Hammer Company has a factory in Frankenhardt, Germany. In our history, our facilities have increased two times now to 24,000 square feet of manufacturing space with an annual production of over 50,000 sets of piano hammers per year.
What are the steps in making hammers?
Hammer making looks to be very easy: Take some wood, some felt and put both into a hammer press and the hammers are finished. But it is not that easy. The whole procedure is much more complicated.
Everything starts with the felt. Felt is a natural product and based on Merino wool (Merino is a type of sheep with incredibly fine and high curled fibers) from South Africa, New Zealand or Australia. In these countries the Merino wool will be selected into different grades. For making hammer felt only a high grade wool fiber can be used. Then the raw wool comes into a cleaning process to Europe where all dirt, sand, dust, mud, vegetarian parts are washed out. This process is called carbonizing under the use of sulphuric acid. However, this acid is counter productive to hammer making as it has the undesired effect that a lot of natural lanolin will be also washed out (and the acid also is not good for the environment).
Natural lanolin (also called wool wax ) is very important to keep the natural resilience in the hammer felt which greatly affects piano tone. To retain this lanolin, Abel started the BIOFELT PROJECT 2003-2006 (sponsored by the European Union) with the result of a felt called NATURAL FELT which did away with harsh chemicals in the washing stage of felt making. This is a more natural product – not as white in color but incredibly versatile in sound. The use of this new Abel Natural Felt is responsible for great success in the piano business in our company.
Felt sheets will be then cut into strips after the sheets have been carefully controlled. The single wool fiber is still in a curled position. In the hammer press the felt will be pressed around the hammer moulding to stretch the wool fibers and to build up the resilience in the hammer felt. This procedure is the main secret of the hammer production. All hammer makers have a slightly different philosophy with this. Here is where Abel’s 55 years of experience in hammer making from Helmut and Frank come into play. Understanding the whole process from “Sheep to Hammer” is the basis of the high quality Abel hammer production.
Although we have our own brand of felt, we also incorporate other felts from other makers to give a wide range of choice so that each maker can select hammers suited to their needs and guarantee the Abel high quality standard of manufacturing.
What’s the difference between cold and hot pressed hammers? How does that affect the hammer head?
Cold pressed means that the felt in the hammer press form will be pressed with no heat or almost no heat. This guarantees that the natural resilience of the wool fiber will be kept alive. Hot pressed hammers in a heated press stabilize the wool fibers however it means that the natural resilience is gone and the hammer felt has lost its elasticity and the ability to create a maximum range of sound colours. The Abel hammer production is a cold pressed process for this reason.
Why are hammers measured by weight? (for example 16lb hammers)
Hammers need a different weight because the pianos are different in size. The bigger the piano, the more weight is required to bring the long strings into vibration and to create maximum sound. For this reason especially the weight and size of the felt are important. A big hammer has a lot of concentrated resilience in the felt to stimulate the string to maximumize sound producing energy.
How does the wooden moulding material affect the hammer?
Different hammer wood is important for different weight. Especially big pianos need larger felt with light hammer mouldings. The large felt is important to maximumize sound vibration and the light woods like walnut and mahogany keep the total weight on a level which makes piano playing possible. So if you combine large felt hammers with light wooden mouldings, the overall weight is manageable at the keyboard.
What is the purpose of underfelt? Do colours designate manufacturer or something of function to identify a design or a time period?
When the first hammers were built the hammer makers did not have the same size felts available that we have today. It was necessary to make a hammer with different layers of underfelt and a thin top felt outside. Nowadays, we can make the same size of hammers with one layer of underfelt and a midsize topfelt or with no underfelt and a big size topfelt. The quality of the underfelt is always the same. But the underfelt can be dyed with different colours to show different brands.
How does quality of felt affect tone? Within one sheet of felt there might even be discrepancies in tone, correct? What felt does Abel use?
We use various felts from different makers. Different felt manufacturers each have a ‘signature’ in the type of felt they make. The combination of felt and felt making procedures will result in different sounding hammers. In this way hammers can be individualized for customized requirements. Felt is a natural product. There are natural discrepancies within a sheet and from one sheet to the next sheet. It depends on the ability of the hammer maker to realize these discrepancies and to select the felt strips. Abel has skilled people who test all felt strips by hand and with their experience they select the strips in to different grades like soft, medium or hard. We call this the “outside quality”. The inside quality depends on the different raw wool and manufacturing process of felt in the felt factory. That means the inside quality describes different characteristics of felt from different felt makers. At Abel we are always in discussion with our felt suppliers to keep the inside and outside quality of the felt sheets within an acceptable quality range. Abel is in contact with all hammer felt manufacturers worldwide which allows us to always select the right felt for our customers and retain diversity.
Density of felt also produces really different results. Is there a way of determining sound from a certain hammer from density and/or elasticity?
The density can vary from one sheet to the next sheet and also within a sheet. As long as the density is within the tolerance of the Abel specification the felt can be used in the Abel hammer production. Density of felt sheets can be determined with the felting process, the milling process and a pressing process. Most important is the felting and milling which enables the wool fiber to interlock and to build up a system of fibers with a maximum elasticity when the felt becomes pressed around the hammer moulding. This complicated procedure has a big influence on the sound of a piano. A hammer with a lot of resilience and a lot of natural life in the felt can create a wider tonal range. The best felt to reach this goal for our production is the ABEL NATURAL FELT. Hammers with less resilience and stabilized wool fiber do not have the ability to create such a wide variation of tonal colour at the piano.
I just want to say thanks to Norbert for allowing us a small glimpse into the art of hammer making. In addition to manufacturing of hammers, Abel also performs operations related to hammer customization called shaping, coving and tapering. Of interest to some wanting to preserve a vintage instrument, Abel also has the capacity to re-felt hammers on existing mouldings. This keeps the wooden shanks and flanges intact and keeps the authenticity of the instrument. Amazing! Hope you enjoyed this interview as much as I did.
Is he a spy? No. Is he famous? No. But this one man’s company has single-handedly infiltrated most of the major names of pianos in the world. 200,000 pianos per year to be exact! Who is he? Jack Brand. Haven’t heard of him? I hadn’t either until the interview with Del Fandrich a few months back. After some preliminary investigating, I found out that Jack Brand owns a company in Canada called Brand Felt. So what does this have to do with pianos? Jack Brand, third generation felt maker along with his father, Klaus Brand, re-established the German Weickert/Wurzen production facility, the oldest, most respected felt maker of piano felt in the world. I queried Jack a few months ago about his interest in shedding some light on the felt making process and he agreed to do this interview. I’m so excited to share his words. I’ve only scratched the surface and already I’m finding that felt making is more about art and intuition than formula; that you could spend a lifetime studying how hammer felt affects piano tone so drastically. Established in 1783, Weickert is over 230 years old! The trade secrets, production notes, and piano technician feedback have been handed down so that this closely guarded secret of felt making lives on. But don’t take my word for it… let’s hear it from Jack.
Weickert and Wurzen are some of the oldest names (THE oldest??) for felt manufacturing in the world and yet the Weickert felt has been “re-introduced” again for hammer manufacturing, correct? Can you tell us a little history about the name and origins as well as your involvement with Weickert and Wurzen?
Wurzen is the oldest existing felt plant of wet processed felts in the World. The oldest. Basically, I was very lucky to come across this beautiful opportunity to re-introduce the old legendary Weickert Felt. All the know-how had disappeared between 1945 and 1991.The Weickert company was expropriated in 1945 by the Communist government and the family fled to the West. The last owner of the company was Alice Weickert, who was an American and had married into the Weickert family. Steinway New York was one of the largest US customers for Weickert hammer felt. I am the fourth generation of textile makers, third as felt makers in the Brand family. All previous generations lost everything due to wars and expropriations, my dad and mom started in the West with nothing after WW2. I am the first in four generations who can build on something.
In 1991 my dad asked me if I was interested in coming back to Germany to look at my grandfather’s plant which couldn’t be salvaged and also at the former Weickert felt plant.
To make a long story short, my dad and I re-privatized the old Weickert plant in 1991. We got a phone call from Renner, Germany asking us whether we could produce the old Weickert felt. We were lucky, the old production recipes were handed to me by an old former production manager of Weickert’s. We ran some materials and the hammers were sent anonymously to Steinway. The response from Steinway (who did not know who had made the felt) was:
– this felt reminds us of the old Weickert Felt
– where is this felt company?
– and we want more
The rest is history. The PTG (Piano Technician’s Guild) of Germany came to the Wurzen plant in 1992, and conducted blind tests on four different grands and the difference in tonal result was significant. After that our supply for Wurzen/Weickert hammer felt was always sold out. Capacity has steadily increased to the point where today annually 180,000 to 200,000 instruments are outfitted with Wurzen felt, about the same amount as in 1903 when ‘Weickert’ felt already had a widely recognized name in the piano world.
Your company Brandfelt.com – how did you get into this business? Did you grow up always wanting to manufacture felt?
I basically learnt felt around the breakfast and dinner table. Our living quarters were at the felt plant. My parents sent me to Canada in 1971 because they wanted me to grow up in a country where there hopefully would not be wars. A small felt plant was founded in Toronto, something to fall back on, in case everything gets lost again thru political turmoil.
Personally I am a production/product development guy who identifies with a natural product like wool felt and who got lucky to stumble upon the challenge of piano felts, which is probably the most difficult felt to make. My colleagues and I didn’t invent the Weickert hammerfelt production method, we only re-introduced it because of fortunate circumstances together with determination and real interest in the product by a whole bunch of people in our factory. At this point I also want to thank all the piano builders and hammerhead makers in the world who showed genuine interest in making a better product and let results speak for themselves.
Piano felt is a small part of our overall world sales, but it is one of the most challenging and interesting ones. We have manufacturing and converting plants in USA, Canada, Europe and Far East.
Let’s get into hammer felt making. How many basic grades of felt are there?
First of all I would say there are today about four major different manufacturing methods in the world for piano hammer felt.
1) I call it the Royal George method out of England, whose technology was purchased by a Japanese felt company in the early 90s,just as the Wurzen /Weickert hammer felt method was being reintroduced into the market place. Royal George as a felt maker does not exist anymore.
2) The VFG method which is a manufacturer out of Germany (in the former West Germany before German reunification in 1989).
3) The Japanese/Chinese method which existed before a Japanese felt company purchased the know how from Royal George, England.
4) The Weickert/Wurzen method which was developed in 1847 near Leipzig and which by 1861 was internationally recognized. By the early 1900 ‘s the J.D. Weickert Piano Forte Felt Company supplied top hammer felt for about 200,000 annually world wide.
Each of these felt methods provide different resiliency or elasticity effects in the felt, hence different results at the hammer head maker and different tones at the voicing stage (because each type of felt will react different in voicing even if hammerhead making method, voicing method and type of instrument are the same)
Each felt manufacturer offers in addition different grades. The Wurzen Felt company offers 4 different grades:
-Piano (which can also be used for grand instruments)
-Weickert Special (the latest and probably also the best in most instances, especially for grand instruments)
All these four different grades by Wurzen are being produced in accordance with the basic principles of the legendary Weickert hammerfelt manufacturing method. The difference in the above felt grades can, for example mean different wool blends and/or slightly changed processes, for example with more or less hand labour in the different stages of production. But we always follow the old Weickert method which nobody else does in the world at the moment. Basically the different grades offer different kinds of elasticities to the hammerhead maker and end user. Weickert in the olden days also carried four different grades of top hammer felt.
What exactly is virgin wool? I presume it doesn’t refer to non-promiscuous sheep…hahaa Do piano hammers primarily use virgin wool?
Virgin wool is wool shorn from live sheep, not dead sheep (usually raised for meat production. Those wools are called skin wools which often are chemically removed). Usually live animals get shorn twice or once a year depending on the food environment and what type of length or fineness of fibre is required. These are virgin wools.
So the big question: What raw materials and process make for great piano felt? What factors affect tone?
Using the right fibres is very important and a prerequisite. The Wurzen/Weickert felt company has a long tradition of knowing what fibres are best suited and how these fibres have to be processed after they are shorn from the sheep. We have our own company specific recipes and specifications, which we consider proprietary. But the different steps in the manufacturing method are essential to provide good tone results in the end (fibre blend, mixing, carding, felting, fulling, finishing). This is where the real know how lies and which differentiates the Wurzen/Weickert felt from all other methods in the world.
In my seminar on the principles of felt making I hand out identical pairs of felt samples which represent the different stages of production, i.e. felted or fulled material but which feel quite different from one another in your hand when you squeeze, bend or just touch them. The pairs of samples are identical in fibre, dimensions and weight and still one will feel harder or stiffer than the other (or one surface feels smoother and the other rougher). Why the difference? Well it is the difference in production method. For example the one sample may have been exposed to high temperature steam whereas the other to low temperature steam affecting the moisture content in the felting and interlocking of fibres process (for fibres to interlock properly the scales on the fibres have to properly open up before they can interlock which only happens if you have the right temperature and moisture content),the right stoke and speed settings of the felting plates, plate patterns, type of transportation cloth on which the material gets felted, etc…
The point is the resiliency/elasticity of the product always changes if one changes any of the parameters in the production process. So that is the craftsmanship which one has to attain thru a lot of trials and errors. Specs of weight and dimension and which fibres alone don’t define the elasticity of hammer felt. One needs to know how these wool fibres are being processed under what parameters at each step of the production process.
The end result is a certain felt elasticity which stands for, in our case, for the Weickert method of hammer felt making. Generations of felt makers at our plant in Wurzen developed it in conjunction with and with feedback from piano builders and hammerhead makers since 1847. The Weickert method is proven and with the help of a good hammer head maker who will adjust his method to our felt, it will produce a beautiful tone. It is very important to work closely with a hammer head maker and also with the piano builder or piano technician to get optimal results. You can have great felt but without the right hammer making method you will end up with mediocre results. Vice versa a good hammerhead maker who knows his stuff and uses a mediocre piece of felt can still get a decent result but not the optimal one.
We know of many examples where the identical Wurzen felt hammer specification was made into hammers by different hammerhead makers for the same piano factory customer, one was good and the other was rejected. The conclusion is that without all three parties working closely together (felt maker, hammer maker, piano builder) you almost have no chance to get the optimal tone result.
To answer your question ‘what affects tone’ I would say it is almost endless but it helps to know what felt and which grade is on your hammer,who made the hammer and what method was used (ie hand vs Hydraulic press, prepress or not, shape of how felt is cut from sheet, what temperatures and times in presses etc…) and what design of instrument and tonal taste one wants to achieve.
The art and science behind felt making, the experimentation, the feedback from builders and technicians – it’s amazing that the Weickert “secret recipe” was not lost. Pianos around the world might have been changed forever had these production notes not have been found and handed to you.
Yes! The basic trade secrets were handed over to me by the then production manager in 1991 who in turn got it from the previous production manager who was still working during the Weickert family era. The last production adjustment to the Grand D hammerfelt spec production sheet for Steinway was initialled and dated in 1933.
Wow! That’s incredible. For those wanting to see felt making in action, here’s a video link to the Brand Felt Company in Canada. I’ve learned so much about an area of pianos I knew so little. And scratching the surface one quickly realizes how broad this speciality is. I just want to convey my thanks to Jack for taking the time to do this interview. Your insights and expertise are not only helpful but inspiring and captivating.
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