Posts tagged touch
When you ask a child to draw a picture of a car, invariably it looks like this – wheels (with spokes hahaa), windows (again with panes lol) and exhaust. Much is the same when we think of pianos – black and white keys as well as strings and hammers. Everything in between magically gets glossed over. But it’s in the attention to such details that make a piano go from just ho-hum to exceptional. There are times that you sit at a piano and it REALLY responds. That piano makes you not only sound good but it also makes you want to play MORE! That’s because someone somewhere in the world has connected the dots from keyboard to string. More accurately, that’s the evolution of many hands spanning 200 years or more with the inception of keyboard instruments. It’s naive to say that one person designed the car as we know it today… so too many people have been involved over the years with the development of the piano.
But there are four basic elements from which we derive “good” touch at the piano. They all must be in check for a piano to function. And they are:
The down weight refers to the pressure required to press down a key on a piano. The up weight is the weight needed to bring the piano key back to resting position. Friction is the perceived weight on all the joint and moving parts while the action ratio is the lever system (called whippen assembly) that multiplies the speed, weight and force of the hammer from the key.
So… in my curious nature, i start asking questions. Why do we need friction? It’s not that we NEED friction but too little of it, and parts are usually too loose and will start producing noise. Too much of it (as on the Chickering grand i just worked on) and the touch feels too heavy. Concert instruments should range between 50 and 55 grams of touch with friction representing 10-15 grams of that touch weight. With too much friction, the piano i just worked on clocked in at just over 80 grams of touch – completely unreasonable for normal playing. Question 2 – well… why not just counterbalance the touch using weights in the keys? If you’ll notice on the sides of your piano keys there are small circular weights made out of lead. Well the lead weights will have some effect for the initial movement of the hammer but in dynamic playing those lead weights will not compensate for rotational inertia at all. Nor will they do any good for either friction or up weight. So why not then just have really light parts and light friction? Good idea but… the speed of the key is also determined by the return… the return requires weight.
The balance then is this – 2 elements of the four are relatively easy to control while 2 are not. The action ratio – the intrinsic design of the piano – not so easy. That’s like saying “Can we just change the pistons on this engine?” Not easily. The second part is the up weight. The up weight carries direct correlation to the hammer weight alone. The other two factors – friction and down weight can be readily altered. Friction is by far the biggest culprit that i’ve seen. And down weight can be counterbalanced with the aforementioned weights. Once the balance is achieved however, the piano becomes a wonderful and inspiring instrument. Below are two pics of lead weighting this last week – some tools of the trade and different lead weights across the keyboard ready to be installed.
Recently i’ve had the opportunity to work on a church piano – an older Chickering. But i must say, this piano was an interesting one to tame. I use the word tame because it was out of control. The touch was not only uneven but INCREDIBLY difficult to play. Most fine pianos have a touch weight of about 50-55ish grams of weight at the key. This one was a whopping 80+ !!! First things first… chase down the friction. That blog will be for another day though. After friction was in the ballpark, i was still faced with a piano that had a touch of 65ish grams. Time to consider putting this piano on a diet. Yep. You heard me. This piano was overweight and i was about to transform the touch.
So where does weight come from? Many months ago i wrote a blog on piano weights. It can simply (and yet so difficult at the same time) be measured in 2 forms – static weight where we are doing a dead lift – the hammer has yet to move. The other is created by rotational inertia. The hammer has started to move… how much effort is required to continue to move the mass of the hammer. The former mainly deals with soft playing… we’re not concerned about velocity but simply getting the hammer in motion. The latter however deals with everything above soft playing and truly is the more important factor. Static weight can be counterbalanced in the key like a see-saw. Rotational inertia however can really only be changed through the mass of the hammer itself. Because static weight again really only affects soft playing, when i sat and just played the piano (after friction was removed), it still felt heavy and burdensome. So it was time to trim the fat – reduce what i could on the hammer without compromising either structural integrity or tone. How does one leave the strike point of a hammer the same and yet reduce dead weight? Take a look at the pics. The one on the left is the original. Square and bulky. The one on the right – the more parabolic shaped one is one i adjusted. The tapered ‘shoulders’ of the hammer offer insignificant contribution to tone… if any. And so i spent the next 3 hours shaping hammers. Take a look at the two ‘tails’ – the end parts of the hammer. On the left – one that is tapered while the right, original. The net result? Reduction in about 1.3-1.5 grams of fat. One point three??? Perspective here… a nickel weighs 5 grams. You ask “How does anyone get excited about 1.3 grams of weight?” Ahhh therein lies the magic. Every piano has an ‘action ratio’ meaning one gram at the hammer accounts for usually around 5 grams at the keyboard. OK so do the math… this piano has a 5.5 action ration. 1.3 gram reduction x 5.5 action = 7.1 gram reduction of touch weight – the exact amount i needed to make this piano feel dynamic and alive. I’m so happy! 😀
Dip refers to the distance the key travels downward. So from the very top of the keystroke to the felt cushion at the bottom, the dip is the distance between the two. Why talk about dip? All pianos should have the same distance right? You would think that this is standardized but it’s not. And believe it or not, 1 millimetre makes a HUGE difference in dip. OK so there are some basic guidelines that piano makers follow. Historically 3/8 of an inch was the standard. This is just shy of 10 millimetres ~ 9.55 to be exact. Personally i tend to lean towards just a hair past 10. Bosendorfer publishes 10.2. Yamaha and Kawai are in the vicinity of about 10.0 to 10.5. I find that ‘shallow’ pianos – ones with under 9.5mm and ‘deep’ pianos – more than 11mm are ones that stand out. And what happens if this is adjusted too deep or shallow? Well, too deep and the keystroke feels a bit like an army tank. Quite often i’ve heard it said that the piano feels ‘clunky’ or heavy. This stands to reason because of the amount of travel your fingers are doing. It requires a lot of effort to play a deep keyboard. Too shallow and you may experience lack of power or a feeling that you’re hitting a wall. Because the benchmark is closer to 10 these days, a 9.5 or shorter dip results in feeling somehow confined.
So better than spinach or artichoke dip, a good key dip results in tasty playing.
Every piano has one… a black hole. It’s the place where all the pencils disappear to. Paperclips magically are sucked into it… Heaven forbid anyone should be doing their theory homework at the piano and an eraser falls inside. And once inside the abyss… gone forever! HAhaa… at least that’s what i used to think when articles would fall inside the piano when i was a kid. And on pain of death we were threatened to never go tinkering around the inside of the piano (which is still probably good advice for kids and pianos…lol). So when the piano tuner would come, he would unravel the mysteries of the universe… “Well… looks like that click sound is actually coming from a pen that fell inside. Oh and here’s another pencil.” I remember seeing the inside mechanism of a piano for the first time in my early teens. (Formally called the “action”). When i witnessed the hammers and levers i remember having this brainwave. “Sir? Can you make the keyboard on my piano heavier?” We had an old upright piano and with 4 kids – 3 of which ended up with diplomas in piano, you can imagine the beating it endured. But when i went to my teacher’s place where there was this beautiful modern 7′ Yamaha grand piano, i noticed how vastly different the touch was. And so the answer from the tuner? Simply “No”. No explanation. End of Story. I thought to myself, in all this gobbledeegook of levers maybe there was some adjustment that could be made to give me a grand touch. I was young and naive and this technician had no time to explain and so i was left with no alternative than to think that it’s impossible.
For the most part, however….unfortunately he was right. I’ve had MANY people ask me to transform their piano into a firmer touch but to understand piano touch more, i’d like you to think of your piano like a scale. On one side is the key of the piano – the black and white notes. On the other side remain the hammers and the action. So most pianos have about 55-60 grams of touch on each key. What that means is:
Finger Pressure (55grams) = Hammers + Friction
Most of the weight of a piano is in the physical motion of the hammer itself. Now if you know anything about hammers, put one on a scale and you’ll find out that it weighs about 8 grams. Attach it to a piano action and all of a sudden, there is a 5:1 ratio of hammer weight. What that means is that the lever system in the piano multiplies the hammer weight by 5. An 8 gram hammer then will feel like 40 grams at the keyboard. Add 15ish grams of friction and VOILA! Piano touch. A 9 gram hammer (times 5=45) plus 15 grams of friction forms a touch of 60 grams at the keyboard. ONE gram on the hammer makes a 5 gram difference at the keyboard. When you think that a nickel weighs 5 grams, adding one-fifth of that is not a whole lot of weight and yet you’ll EASILY feel the difference installed into a piano due to the ratio. Make sense? Is it not possible then to simply add friction to the piano? Adding friction is not the answer. Friction is a careful balance. Too little and the piano feels too ‘loose’ and results in noise. Too much friction and the piano has sticking parts and feels sluggish. If your piano is old however, you may have worn out “joints” or pivot points. There are 2 areas which can be monitored which make any piano feel more “positive”. One is key bushings (see the article entitled “Aye There’s the Rub) and the other is called the hammer flange. (A flange is just a fancy word for hinged part on a piano). The hammer flange… if you follow your eye down the stick (called the shank), you will see that it is jointed at the base. New flanges (albeit costly) and key bushings are the biggest culprits for too much/too little friction. And so without opening pandora’s box more… my original question to the tuner: Can’t you change simply change the touch on the piano? Operative word in that sentence is “simply”. It can be done. It’s just not simple.
Recently i had the privilege of working on a brand new piano which will remain nameless. The instrument was adequate but one problem kept cropping up – and that is that the necessary friction was all over the map. When you play a piano, in the 6000 moving parts, friction accounts for about 15 grams of touch on the instrument on average. You might think that absence of all friction would be ideal but that is not true. Some resistance is required. So what happens if the friction is excessive or absent? You get a poor playing piano with a VERY inconsistent touch. On this particular piano, the joint at what is called the flange was completely out of line. In addition, key bushings were WAY too sloppy. How does that happen when a piano is brand new? Simple. Use green lumber during the manufacturing process. Wood that has not been dried properly is known as “green”. If the wood contains too much humidity and has not been thoroughly dried naturally or in a kiln, the wood eventually will dry out and also warp. In this case, the once fitting joints obviously were not made with properly cured wood. It is difficult from the consumer’s point of view to determine this. Reputable companies cure their wood for up to 2 years before manufacturing. Companies of ill repute simply mill the wood and insert into the piano. What ensues is a whole raft of issues to deal with later. My advice? Be REALLY discerning on a new piano with regards to touch. If it feels ‘sloppy’ or wiggly or tight, there’s a good chance it has substandard parts – ones that are not correctly fitting. And word to the wise: if the wood isn’t right, there’s a good chance the felt is poor, the design is poor and other materials are also cheaply made. Buyer beware: you DO get what you pay for.
PS… the picture is one of a grand action. The red circles are joints – a steel pin surrounded by cloth inserted into wood.
I’m the first to admit, i’m not into physics – not to say i don’t enjoy it, but i’m untrained in the area of advanced physics. What i AM interested in though is the practical application of physics – more specifically the touch of the piano. A few years back i had a Yamaha C5 in my shop. Beautiful instrument. It was apparent however that the touch was simply ALL WRONG. It had been monkeyed with. So i applied usual regulation specs and it turned out nicely. However, there was one niggly thing sitting in the back of my head that just wouldn’t go away… and that is that the instrument felt somehow sluggish. At the same time i had been looking over some ideas on key weighting which is the concept of adding/removing lead weights into the keys to achieve a more balanced keyboard. For those who are unaware, key weighting is a common practice in MOST pianos. The key weighting is part of the balancing of the equation to achieve a certain initial weight at the outset of the key. (And if you don’t believe me, next time you’re near a grand, press down a key and look at the neighbouring keysticks – you may just catch a glimpse of a circular led weight inserted into the key. ) Anyhow, for kicks i thought that i would key weight this C5. Sure enough the touch improved dramatically. End of story? Nope… i was still bugged by that same sluggish feel. So i rechecked my work and i must say that at soft playing, the piano was EXCEPTIONAL. It wasn’t until you hit the fast notes that i noticed the problem. Well… the piano ended up selling but that problem lingered in the back of my head.
Fast forward 3 years. I have a client who is an engineer. We were speaking about physics, touch of the piano… and he just so happened to mention Kinetic Energy. I had a small epiphany… i thought to myself… IT DOESN’T REALLY MATTER HOW MUCH KEY WEIGHTING HAPPENS BECAUSE THAT ONLY REPRESENTS THE HAMMER AT REST POSITION. AHA! No wonder that piano felt great at soft volumes – there was little inertia and the key weighting was ‘closer’ to the ‘at rest’ weight. So… the ONLY way then to affect touch is to change the mass. Ok gears turning here… if i could measure the velocity of the hammer in travel (ie radar, infrared beam etc) and the weight of the hammer i can measure… then i would be able to calculate the Kinetic Energy. What that means then is that one could ‘reverse’ model the ‘feel’ of great pianos. The rotational radius is similar as pianos have become more standardized. The combination then of calculated KE and key weighting would make for an undeniable touch don’t you think? So if KE=1/2MV2… we know mass… if only i could determine velocity… hmmm… thinking thinking… could i borrow my cop friend’s radar gear? lol.