Tech Talk

The History of Piano String Tension

Blah! The title of this sounds to most as exciting as watching paint dry.  Operative words being “to most”… to me however this is one of the more interesting charts i’ve seen in a long time.  Back in 2005, published by Europiano, Juan Más Cabré wrote this article showing the differing string tensions over the last few hundred years. Everything i know about string tension i learned as a child with a bread pan and rubberbands. Hahaaa… i used to make musical instruments when i was a kid. What fascinated me though was the thickness of the rubber band and the sound that would happen at a certain pitch. This is exactly what’s going on in pianos. The graph shows the earliest of pianos from Cristofori (in 1726). That string tension is little more than that of a harpsichord. It became evident that a stronger frame would be neccessary to implement higher tension. With higher tension comes more singing tone. Next on the list is Silbermann who asked Bach for some input. Silbermann contributed the damper device (similar to a damper pedal) to the piano. Shortly thereafter in the Classical era (Beethoven’s time) more and more iron was added to the wooden frame so as to boost the string tension – again with more singing, sustaining sound and also more resonance and power. Enter the famed Steinway and Bosendorfer. Interesting to note is that “more is not always better”. There have been pianos that have had higher string tensions (as in Ibach) but manufacturers decide what sound is pleasing. This is part of the backbone of ‘scale’ – the trade secrets of piano makers. Length of string, thickness of wire and tension of string all add to the sound. To get a mini idea of this, play around with a bread pan. It really is a fascinating exercise in string tension. And after that… just make some fresh bread. Nothing beats music and food together :)

How Often Should Pianos Be Tuned?

There hardly is a day that goes by when people don’t ask “How often should i tune my piano?”  To understand this question, there are a few variables you need to be aware of.  Firstly, there are roughly 18 tonnes of string tension pulling on most pianos at any given time.  To say to me “We hardly ever play it” in some ways is irrelevant because the strings are still under tension regardless of whether your hand touches the keys.  That said, pianos that get play a LOT will go out slightly if the tuning pins have not been properly set when tuning and i have noticed that more frequently used teaching pianos require more attention.  Second, humidity change plays a large part in tuning stability.  The strings are not just stretched from one end to the other.  They go over a bridge (much like you would see on a guitar).  That bridge is attached to the soundboard and depending on seasonal changes in humidity, the piano will fluctuate in pitch as the wood expands and contracts.

Now then, once you understand all of that, my usual response when asked how often pianos should be tuned is this: Depends how particular you are in having it in tune.  Recording studios and concert halls have it tuned every time it’s used.  Some churches even locally have it tuned once a month to quarterly depending on budget.  Most teaching studios tune twice a year.  Most families tunes yearly.

“But my piano doesn’t go out of tune that often”… hahaaaa.  I’ve encountered VERY few pianos in my lifetime and i’ve played over a thousand that rarely go out of tune.  My guess is that the piano is just gently creeping out of tune in such small increments that you don’t realise it’s gone out a few degrees.  My rule of thumb is that most people can’t hear when a piano is out of tune up to 6 degrees!  A degree in tuning is called a cent.  A semi-tone is 50 cents.  Full tone 100.  When pianos are out by about 3 or 4 degrees, the piano has still dropped in pitch but may not have been noticed.  Well… wait another year and then it’s out another 3 or 4.  Sooner than you know it, the piano has sunken 12-15 degrees over 3 or 4 years and instead of simply correcting a few degrees, you’re pulling strings.  My advice? Whether you hear it or not, do yourself a favor and keep it in regular maintenance.  And besides, like freshly squeezed orange juice, nothing beats a freshly tuned piano.

Piano Dust… the Sequel

I retract! I repent in dust and ashes. Ok wait a minute… forget the dust part. I’ve seen too much of it lately.  Awhile ago i wrote about the fact that dust is not the enemy to pianos.  Rather, it is humidity fluctuation.  Well… i’m going to modify my statement.  I’ll retract a portion of that.  GENERALLY… dust is not an issue.  EXCEPT when it blocks the keys.  “Dust blocks the keys?” you ask. Yep… seen it… photographed it.  I was asked to work on an older grand piano.  And well… these were not only dust BUNNIES… they were dust… mmmm LLAMAS! Big whopping pieces of dust laminated by years of uncleanliness. (Ewwww right?)  Anywhooo… the problem comes under the keys where there are felt punchings.  Y’see it’s the felt underneath that stops the key from travelling.  Each key is set to a certain depth.  Now what happens when you place a dust…mmmm Llama on top of that felt piece? Exackly… you have a shallow key dip.  Such was the case with the piano photographed.  A couple of swipes with the vacuum and VOILA! At least that portion of piano irregularities was taken care of.  Good as new? Not quite… it was still 100 year old piano… more like… on to the next challenge.

Piano Signatures

The other day i was pulling apart an old Heintzman grand piano – arguably the best make of piano ever built in Canada.  Rarely do the strings come off on an old piano.  In fact, there was evidence that this one had never had new strings since new.  I’m the first person to touch the strings in almost 90 years.  I find that fascinating – not that the strings haven’t been changed but that this piano has not been touched since new.  On the back of one of the understringing slats however i didn’t expect to find the signatures that you see in the pics.  There were initials were MCR and he dated one of them August 27, 1923.  As well, it reads “R. Sill” or “R.Gill” and the production number 394.  I find it not only interesting but also humbling to be part of the life of a piano.  I remember lifting the cast iron plate with a large engine hoist out of a piano and underneath it had a signature.  What fascinates me is that we touch history, it comes to life.  We get transported back in time to when piano makers were building these one at a time and some technician in the factory signed his name on a piece of a piano that will never see the light of day.  It’s just interesting to me… it’s a piece of history that we get to see for a brief moment.  But not only that, to make this piano function again, I need to re-install these same wooden slats back into the piano.  That means then, that this signature was buried for 90 years, i’m potentially the only one to view it and then it gets concealed possibly for either another 100 years… or possibly never if the piano doesn’t get rebuilt again.  Just thot i’d share someone’s work from nearly a century ago and bring to light that which was in the darkness. Below is a picture of piano keys, each one signed by the technician who tuned it… check out the dates.

Bechstein Restoration – As Good As Old

I was asked to tune a piano recently that i had restored about 10 years ago.  What struck me as i sat there tuning was the quality of this instrument from yesteryear.  More than that, from turn of the century… ok i guess we need to qualify that right? hahaaa… from the turn of the 20th century, great piano design was well under way.  In fact, some of these piano designs are still revered and respected and are from a time known to many as the ‘golden era’.  Although i agree with many that there are SOME pianos from 100 years ago that were brilliant, there were many many more that were just coming of age.  The highest level of pianos however – the Bechsteins, the Bluthners, the Steinways, Bosendorfers… the list goes on where pianos were made to such a high degree of craftsmanship that they became manufacturers by royal appointment…  I find those pianos are very musical indeed.

The problem i have though is that many say “Oh nothing beats my grandmother’s old piano”… did they just refer to this old beat up, worn out piano as the apex, the very pinnacle of piano design? I must go on record by relating a saying that a wise old piano technician once told me when i first entered the business.  He said:

“Glen, there are two myths in the piano world: Older is good. And newer is better”.  Sounds paradoxical but it’s true… i’ve played old pianos most of which are just mediocre.  I’ve also played brand new pianos that you would think are brilliant and are sub-standard.  The moral of the story: quality in manufacturing and design still create beautiful music but you need to wade through the myriads of pianos to search for the gems.  If you had the chance to play this old C. Bechstein, it would without a doubt confirm that some will remain memorable.

1810 Broadwood Square Grand Piano

 

 

 

 

 

 

This summer I had the opportunity to play a piano in a museum. My home town of Winnipeg, Manitoba has an old fort from the 1850’s where all the workers dress in period clothing. It was owned and operated by the Hudson’s Bay Company and was functioning a decade and a half before the country was even established. Inside the walls of this stone fort are a fur trading post, a general store (where they sold Lea and Perrin’s Worchestershire sauce – established in 1837!) and the governor’s house (among other buildings).

The governor’s house is more opulent. It has fine furniture and lo and behold, a piano! It was a Broadwood (which was the piano maker for royalty by appointment). The details were incredible! Gold gilding, pin striping of inlaid brass and various kinds of woods (mainly mahogany). It was only 5 octaves and had no cast iron. The piano was brought over by boat and ox cart – an incredible feat in the 1850’s.

After taking many pictures, the governor’s wife asked if i know anything about pianos and a long conversation ensued about Broadwood and the construction of this particular instrument. She then said “Would you like to play it?” Apparently few people get to play this piano. What a privilege! Because there is no cast iron to create tuning stability, the piano was pretty out of tune and the pitch was about 4 keys down but was still interesting. It sounded more like a clavichord or harpsichord than what we know as a modern piano. The hammers are TINY! Made out of various layers of what looked like felt and leather. The action was direct blow without any real sort of repetition mechanism and so the key weight was feather light. Also worth noting is that there is no pedals of any kind. They were implemented shortly after this time period.

Beethoven received a gift of a Broadwood piano only 8 years after this one. It’s incredible to hear instruments as they would have sounded in the early 1800’s. Beethoven wrote back with this statement after receiving his piano “I shall regard it as an altar upon which I will place the choicest offerings of my mind to the Divine Apollo.” Such fun to see and hear the earliest predecessors of the piano. Enjoy the pics. BTW, the coolest part on this piano were the built in drawers that hold sheet music.  Why don’t we have those today??? Click on the photos for larger images.

Piano String… Repair or Replace?

I was introduced to the concept of repairing bass strings only 5 years ago.  A fellow tech friend of mine showed me this simple knot in order to ‘save’ a bass string.  Now before i get down the path too far, some of you might be thinking…’well why not just throw it out and replace with a new string?’  First of all, it it’s plain wire, you do.  Plain treble wire is readily available and there’s no magic in the wire.  When it comes to the bass strings however, they are custom made for the size, model and scale of each piano.  The core wire, the copper winding, the length of the copper and the speaking length all come into play.  You don’t just pick up the phone and ask for a new one… especially when the company has been out of business for 60 years.  In addition, a new bass string will not carry the same ‘weathered’ sound as a the more brilliant brand new string.  Aged strings tend to be duller.  So there’s a lot to be said for splicing a bass string.  This knot (shown in a diagram and also picture) tightens up wonderfully.  There are a few criteria however…

1. The break cannot be in the speaking length.  That’s the part where the string sings.  A knot will inhibit vibration.

2. You must have enough steel to make the knot.  Most recently i went to a home where there was a broken bass string and although i was hoping to splice, the broken wire only had about 1/8″ or about 5mm before the copper… not enough to work with

I usually use brand new wire of the same core thickness at the tuning pin because if it has broken once, it’s probably brittle enough to break again.  Once tight, the string usually acts as normal and you can once again listen to the bass with a continuous flow or sound rather than one note ‘jumping’ out at you.

Pianos and Dust

I get asked ALL the time “What do i do about the dust in my piano”. Let me reassure you that dust is NOT an enemy to pianos. The outside of pianos – the cabinet is simply furniture. The inside – the strings, keys, action – think of it like a car. Do you worry about dust on your car engine? Of course not. Piano keys have a type of dust ‘trap’ which is the keybed. As seen in the picture below, when you take the keys out there are paperclips, dust, coins. None of these affect the piano performance. Heat and humidity fluctuation are the enemies to pianos – not dust.
So go ahead and dust the outside and leave the insides alone. Now if you own a grand and you’re tired of looking at dust under the strings – again, it’s cosmetic but i can understand that you want to have it clean and bright looking. I own a soundboard cleaner which is simply a long aluminum strip that i attach a dust cloth to. When asked to clean under the strings, I remove the grand lid and do a proper job of cleaning. It requires some effort and know-how but worth the results. Just one cautionary note: If you want to either vacuum or dust the inside of your grand, be REALLY careful with the dampers (pictured right). If the wires that hold these in place get bent, they affect the sustain and will require adjustment. My advice, you can dust the gold cast iron, the strings, the soundboard, the tuning pins, but leave the dampers alone. Hope this helps.

Piano Friction “Weight”

So… it was a graph that was bothering me… i couldn’t let it go. I was looking at data from a recent piano where the hammer weight was sloped (as it should be – there are larger hammer in the lower notes of a piano and small ones in the top) and what i found to be interesting was that the frictional component was also sloped. Why would that be? But there was no more time for today…I locked the door, closed the shop for the weekend. But it was on my mind. According to the stats, i needed to reduce about 3-5 grams of friction in the lower hammers. Then i got to thinkin’… what would happen if you had a wagon that was empty versus one that was full. The coefficient of friction would remain the same – meaning that the percent or ratio of friction would be the same – but the load would actually change the ‘weight’ of friction. Thinking again about the wagon… if it was empty it would be quite easy to move right? Load it full of bricks and all of a sudden, the force required to move the wagon increased proportional to the load. So in essence, the ratio doesn’t change but the weight of friction will change with the load. Back to the piano – the hammers i measured were slightly heavy… too heavy in fact for this piano. I referenced my graph again… i was examining the weight of friction and not the coefficient of friction. After i did many checks and balances again on certain joints, i finally did the reduction of weight which you can see the article on entitled Hammer Shaping. What gave me a tickle though was the fact that with the load reduced, so also the friction reduced by the exact amount i needed – a few grams.

PS… don’t know whether the coefficient of friction changes when the friction becomes the kids fighting… <sigh> i remember those days all too well :)

Piano Touch Weight

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:

Down weight

Up weight

Friction

Action ratio

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.

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