Posts tagged string

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 :)

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.

Full Size Grand Pianos

So… over the years there have been many terms bantered about with regards to pianos – terms like “upright grand” or “baby grand”.  In this blog we’re going to discuss what a “full size” grand is.  First of all, i would just like to point out that there is no official guide to piano sizes.  These names have evolved and so their usage is also vague at best.  For what it’s worth, however i’ll give you the ‘insider scoop’ on how retail stores and piano dealers categorize grands.

First of all, let’s set a few ground rules shall we? Full size seems to imply that smaller grands are somehow missing something – as if there is such a thing as a half size or 3/4 size piano… not so.  All pianos have the same amount of keys. All pianos have roughly the same amount of strings.  So what exactly is changing then from one size to another? It’s the length.  The term ‘baby grand’ in my mind is anything 5’5″ and under.  Today we see modern manufacturers producing really small pianos at 4’9″, 4’11″… 5’0″, 5’1″ etc.  In the olden golden days Steinway (among others) consolidated sizes to 5’2″, 5’7″, 6’1″, 6’10”, 7’4″ and 9′.  Yamaha has had huge success with a 6’6″ piano as opposed to Steinway’s 6’10”.  Regardless, pianos under the 5’7″ mark have usually been considered baby.  Full size refers more than anything to string length.  Once you surpass the baby grand size in strings, the piano blossoms.  More so even on the 6’1″ grand. Now at the extreme other end, the term ‘concert grand’ has been reserved for 9′ pianos while semi-concert is the 7’4″ – 7’6″ range.  So if a baby grand goes up to 5’5″ and the semi-concert is at 7’4″, then the term ‘full size’ would fit in the middle there.  So the way i define full size is a piano between 5’7″ and 7′ in length.  Hope this gives you an idea about what we’re talking about.  Just FYI, you won’t magically step over the threshold from one piano size to another, you’ll just hear the difference that length makes when you gradually increase the size.  Take a look at the pics below and see how the rim (the curved end part on the piano) is quite different.  Pictured: Yamaha A1 (4’11”), Yamaha C5 (6’7″), and Yamaha CF (9′).

When in doubt just say “Duplexing”

Duplexing just sounds complex. Complex means it’s complicated. Complicated must mean that you’re somehow smart. And so… (follow the trail) knowing about duplexing means you’re smart. Ha ha. If you’re ever at one of those hors d’oeuvres-type parties and everyone’s dressed in tuxedos and ballroom gowns, you’re going to want to have something to say when they ask your professional opinion about the piano. My advice? Nod… add a few “mmm-hmmmms” and say “Ahhh… Duplexing”…hee hee. Ok enough of my jesting…

So what exactly is duplexing anyway?? Created by the late great Mr. Steinway himself in 1872, it was designed as an ‘added ring’ to pianos – giving more resonance to the tone. How is this accomplished? Glad you asked. Any piano string has what is called ‘speaking length’. This is the live portion of the string which resonates freely when a note is played on the piano. The speaking length starts just past the tuning pins on a part called an agraffe (or capo d’astro… ok i’ll define those some other time) and ends on the bridge. Past the bridge, the string is then wrapped around some sort of termination pin. The tone past the bridge was traditionally considered ‘dead’ tone. But Steinway thought “what happened if we kept this part of the piano ‘live’ or ringing in harmonicity with the instrument”? And so the duplex system was born. Think of it as duple time… duple by definition means ‘double’. So duplexing then is a double ringing part on the piano. How did Steinway make this contraption? He rigged another ‘bridge’ just before the termination point. One that was made out of a series of bars. In fact, if you want to test out the duplexing on your piano (if you have it), simply look past the bridge (which is easy to see on a grand piano) and you’ll spot the parts that are called “Aliquots” (another great party word after you’ve used duplex). You can test how live the duplex is on your piano by simply strumming that portion. An aliquot on a piano is a bar shown in the pictures here. By definition it means “fractional part”. Stands to reason… since we’re adding a fraction of the sound to the tone. In Latin, it simply means “several” or “a few”. Steinway’s thinking was to add either an octave or 5th to the existing tone, making it fuller and richer sounding.

Having said all that… some people just don’t like the extra ring. Solution? Simply cordon off the strings with what is called ‘understringing braid’. (I know i know… too many new words this time around). In the tech world, it’s simply called understringing – anything touching the strings will stop the extra tone and so if you have a technician ‘block’ the tone by adding understringing, it will alter the added ring on a piano. By the way, one experiment i did about 5 years was change the proximity of the understringing with the bridge. It changes perceived tone considerably.

When 50 Cent Ain’t a Half Dollar

Pianos are stubborn! There are no two ways about it. If you pull their strings, they’ll pull back. In fact, it’s a little like a tug of war when tuning. The farther the piano has dropped in pitch (remember that there are thousands of pounds pulling whether you play the instrument or not), the more the piano is going to complain when you pull it back up to pitch. For example, there are 100 cents in a semi-tone. A cent is an increment of pitch. So if you pull strings 25 cents, quite often the piano will pull back 8 cents. Raise the pitch 15 degrees (or cents) and it will pull back 5 cents. Why is that? Most of that pull-back is from the soundboard responding to added pressure.

The following are some tuning fun free facts i’ve noticed in recent years:
1. Solid reputable pianos will fall about 3-5 cents per year. It makes sense then that a piano that hasn’t been tuned for three years will be out of pitch 9-15 cents.
2. Pianos will not stay perfectly in tune if they are out more than about 15 cents. Back to the tug-o-war… you tighten the strings and it will pull back. It is impossible to stabilize perfectly a piano on first tuning that is out more than 15 degrees.
3. It’s a good idea then to compensate for this loss of pitch. Let’s say that A440 is “0” and that the piano is 15 cents down in pitch (-15). I usually adjust my strobe to tune +5 and expect that the piano will then drop by that amount. Crossing fingers, the piano will end up at 0 after completion.
4. Pianos farther than 40 cents down and have strings that look old and rusty, expect possible string breakage.
5. When pianos are farther than 15 cents down, it doesn’t mean that the piano cannot be tuned, it simply means that it would be a good idea to do a ‘pitch raise’ first and then do a fine tuning. A pitch raise is a very fast tuning to bring the piano into the ballpark. Once the piano has settled somewhat to the new tension, it is then possible to tune it at which point, the piano should be stable.
6. Piano wire gauge is matched to the pitch of a note. Even though the wires may look all the same thickness, they’re not. And so when pitch has slidden, the piano also won’t sound optimal. Only when the instrument is matched for the pitch will the tone also follow. Pianos that are flat in pitch usually sound dull and lifeless.

Next time you have your tuner over, ask him/her (providing they have a strobe) how many cents your piano is ‘out’.
PS…you’ll look like you’re in the know

Piano Trivia

Tri-Chord Piano Strings

 

Ok time to do the math.  Here’s the question of the day: How many pounds of string tension are there on one piano, meaning… each string is tightened to produce tone – how many pounds of tension are the combined strings?  Well to answer that, you need some data.  First of all, how many pounds are pulling on one wire? The answer – on average, about 160 lbs.  Next question – how many wires are on a piano?  Well this varies greatly from piano to piano.  “IT DOES?”, you ask.  Yes – it all depends on the design or “scale” of the piano, the length, and the amount of bass strings there are.  “Well aren’t there the same notes on each piano?” 

Bi-Chord Piano Strings

 

Yes, of course there are 88 notes on each instrument but if you’ve ever looked inside you’ll see that there are Monochord, Bichord and Trichord strings.  (Think: Monocycle, Bicycle and Tricycle – need i say more?)  Some notes have one string, some two and others three.  Depending on the manufacturer, the length of the piano (usually longer has fewer bass strings), string amounts will vary considerably.  All pianos have “crossover” meaning that the copper bass strings cross over the steel wire strings.  Sometimes that crossover point is quite high on the piano, sometimes it’s lower.  Having said ALL that… on average there are about 225 wires on a piano (45 bass strings and about 180 treble strings).  

Mono-Chord Piano Strings

 

 So whipping out my handy dandy calculator… 160 pounds of pressure on 225 strings (on average) = 36,000 pounds! or about 18 tons of string tension.  This necessitates having a cast iron frame (which in turn makes the piano REALLY heavy). There…. small piece of trivia you can talk about at the next cocktail party. Enjoy!

Aye, There’s the Rub

Indeed, friction is one of the piano technician’s worst nightmares.  At best, the piano is a simple machine – you depress a key, it lifts a hammer to strike a string.  At worst, it’s a complex mechanism where levers and joints are in contact all the time and each surface area is potential for friction to either be too loose or too great: too loose and the piano feels ‘warbly’ and too tight and it either doesn’t function properly or feels like you have to work too hard to compensate for the touch. 

I learned this only a few years back but the formula for touch on a piano is relatively simple (operative word being ‘relatively’).  There is a 5:1 ratio of hammer weight to key.  What that means is, for every gram of weight at the hammer there is 5 grams at the keyboard.  An average hammer weighs in at about 8 grams (multiply by 5 = 40 grams).  So if average touch on a piano is 55 grams per key, where are the other 15 grams of resistance coming from?? Answer: friction.

One side of key bushings replaced

Today i had the opportunity to redo key bushings on a fabulous grand piano owned by one of the best jazz musicians in the area.  With a lot of playing (both from his own practice and from his students), the bushings around the contact points on the keys were completely worn making almost a ‘knocking’ feel from side to side.  A bushing is nothing more than a substance used to reduce friction between two contact points.  In pianos, bushings are almost exclusively made out of cloth (some people mistakenly call it felt but truly it is cloth – woven together).  The cloth then allows the interaction of joints.  Centre pins are made out of steel and they need to interact with wood.  Without bushings these two hard substances would click and knock together.  As well, friction can be taken up by cloth in varying degrees of thickness.  So the cloth is the perfect substance for acting as the ‘spacer’ inbetween. 

Next time you’re at a piano, test the bushings.  Take one key and swivel it from side to side and see if you sense a knock or a thunk.  This will tell you they need replacement.  Simply steam out the old ones (see pictures) and glue in new ones and you’re good for years to come.

The Eye of the Beholder…

hammers2Quite a number of years ago a friend of mine watched a show on TV about beauty.  What was interesting to note was that they took a number of pictures (i hate to say it…sorry i’m not sexist but…) pictures of women of all different shapes, colours, kinds and sizes and showed them to different cultures asking “Point out the most beautiful”.  The statistics were interesting… that regardless of culture there is a general sense of ‘beauty’.  And before you get your nickers in a knot, let me just say that in North America, they’ve manipulated that concept to the NINES! to the point of disgusting.  It’s created a weird box that women are somehow supposed to fit into – regardless of the fact that most do NOT.

Seguay.

I was tuning a piano this morning – thinking of the concept of beauty in tone; how 8 out of 10 of my customers listen for a similar type of tone.  I was contemplating what the ‘averages’ were in piano sound – that if you were to play a number of pianos, what most people would find pleasing.  Ok follow the rabbit trail here… i was then thinking about connecting a spectrograph (an electronic device that displays a breakdown of frequencies) to pianos that are considered ‘beautiful’ and analysing the correlations of tone.  (i know, i know…piano tuning is boring…lol… i have such thoughts when i’m tuning for better part of 2 hours…lol).  So after the tone is ‘visible’, then look at the physical makeup of the piano – the felt, the strings, the make and model etc and try and reverse engineer the formula.  Why?  Well, there’s this thing called VOICING.  Voicing is the art of manipulating the piano hammers in such a way as to enhance frequencies or remove unwanted frequencies.  When i was young, i thot that each piano company had a certain tone.  Yamaha had a tone, Baldwin had a tone, Kawai had a tone, Steinway had a tone… etc… and to a degree, that concept is true.  But what MANY people don’t know is that the tone can be altered almost up to 50%.  What that means is that you can have an extremely mellow sounding Yamaha – which typically is a brassy bright instrument.  Through voicing, you can change the way the fibres of the hammer strike the string.  Once this is accomplished, pianos can go from very mediocre to dazzling!

Well… my time is up.  I’ll write another blog about voicing some time…promise.  And there you’ll understand the basics how-to’s of the process of voicing.

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