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So I've read that Mason and Hamlin are high tension scale designs.

I've heard that Steinway and Sons S, M, L are low tension designs.

Anybody know where others stand in this range?

Bosendorfer, Grotrian, Schimmel, Yamaha, Steinway B, C etc?

Thanks.

Ulrich Sauter just told me that his pianos are 'low tension'.

[obviously designed for *high attention*.... ]

Norbert

I think I heard the Walter is low tension, where's Del?

I think he said here once that low tension scales tend to be mellow, and high tend to be more brilliant.

The Estonia is a rather low tension scale if I recall too. Please correct me if this is wrong.

Dan

The Walter 190 (with the tenor strings in the 155 to 165 lb range) is relatively low, though not as low as it would be if I were doing it today.

The Estonia (according to the published literature its tenor strings are in the 140 to 150 lb range) is extremely low.

Del

I've sort of wondered about this term, and whether it refers to an absolute amount of tension, or the percentage of tension to the breaking strength or the elastic limit.

You can change the absolute amount of tension by changing the string gauges, but the percentage remains pretty constant and can only be changed by a change of design. Hubbard used the terms long scale or short scale with harpsichords, and indicated them by the length of the strings on the C above middle C. A short scale would have low tension as a percentage of the breaking strength.

I can’t speak for harpsichord designers but, by convention, when discussing piano scales this refers to absolute wire tension.

While the percentage–of–breaking strength (pbs) is an important parameter to keep in mind (it's always best to avoid designing a scale in which strings are regularly breaking) it is not particularly critical through the tenor section of the scale. Even in a relatively high–tension scale like the Steinway D (with tensions in the 190 – 210 lb, or 85 – 95 kgf, range) the strings will be pulled to only about 35 – 40% of their rated breaking strength.

As well, changing the wire size to alter string tension has very little effect on the string’s percentage–of–breaking strength. For example, take a typical note F-33 in a concert grand: with a length of 972 mm and a wire diameter of 0.043” the tension will be 190 lbs and the string’s pbs will be approximately 37%. Increasing this wire diameter to 0.045” (keeping the length the same) will increase the tension to 208 lbs but the pbs will increase only to approximately 38%. Going back to the original wire diameter and increasing the length to 1,017 mm will also increase the string tension to 208 lb. This change will have a greater effect but still the pbs will only go up to approximately 41%.

It will not be the effect of the change in the percentage–of–breaking strength that will cause the tone quality to go sharper and more strident, it will be the higher impedance to motion across the bridges caused by the additional stiffness of the strings and the “tie-down” effect of the overall string plane.

Wrapped strings, of course, are a whole other issue.

Del

Del,
Why as your thinking evolved towards the lower tension scale? Interesting comment about the Walter, I had read a post by somebody once who complained about the 190's lowish tension scale, and how (this individual) felt that it would benefit from a higher tension design. If I had to make a choice I tend towards lower tension pianos (Estonia, Walter, Bosendorfer), but it does seem to be taste specific. What do you like and dislike about lower, and higher tension designs?

[/qb] [/QUOTE]Del,
Why has your thinking evolved towards the lower tension scale? Interesting comment about the Walter, I had read a post by somebody once who complained about the 190's lowish tension scale, and how (this individual) felt that it would benefit from a higher tension design. If I had to make a choice I tend towards lower tension pianos (Estonia, Walter, Bosendorfer), but it does seem to be taste specific. What do you like and dislike about lower, and higher tension designs? [/QB][/QUOTE]


Well, my taste has changed with experience and time. And perhaps I've become some less tolerant of crude and stagnet piano design over the years. I've never been particularly attracted to loud, raucous and unsubtle music and I find increasingly that I don’t care for hard and harsh–sounding pianos. And I’ve reached the age at which I no longer have the time or inclination to put up with them.

I now rarely go to piano concerts that are held in large halls because the piano must generally be voiced so hard (to ‘project,’ you know) it looses its inherent dynamics. Where is the subtlety? The dynamics? I do go to concerts in smaller venues where the piano can actually be voice to perform as a pianoforte and where there is some connection and intimacy between the performer and the audience. I may miss out on seeing and hearing some of the superstars this way, but so what? I’ll enjoy much more the connection with an artist who may well be just as talented — often more — but who lacks the personality drive to enter the business of profession performance.

If one is much of a fan of classical music at all you have to wonder what the original composers would have thought of this tendency toward the monochromatic, loud, fast and slavish reproduction of the works they labored over. If you’ve ever attended a concert performed on a fortepiano you know their instruments weren’t capable of anything like the enormous volume levels being demanded of the modern piano. Even with the advent of the so–called ‘modern’ piano during the mid to late 1800s the voice of the piano was much, much softer and more subtle that what we have ended up with today. (The felt wasn’t felted as hard and the hammer presses were not capable of either the pressures or the heat used to make modern hammers.)

One day before I have to hang up my mouse I’d like to design a modern pianoforte for the home and/or small concert hall. I can envision a long (say, 250 to 300 cm, or 8’ 2.5’ to 9’ 10” in length) and slender (say, 135 cm, or 53” in width across the front of the rim) instrument having a long but low to medium tension scale (i.e., one using relatively thin wire). Coupled with hammers of moderate mass and high resiliency the tonal dynamics would be to die for. It would be subtle and warm yet, believe me, it would be loud enough, when called on, to blast most reasonable folks out of the room. An, as an added bonus, the action would be light and quick due to the reduced reciprocating mass of the action system — less leading would be required to balance out the hammers. Demanding, perhaps, but infinitely rewarding.

High tension scales tie the soundboard system down, making it more difficult to develop a nice solid fundamental. The power is there, obviously, but it is concentrated in the upper harmonics. This is accentuated by the more dense and harder hammers required to drive those (usually) more massive and higher tension strings.

This whole issue has been an evolutionary process for me. My early studies (and studies) into scale evaluation and design were based on what has gone before. There is little written material that really evaluates the tonal consequences of scale tension schemes — we’ve kind of had to work things out as we go along. So, most of my early work was done with the higher tension scales typically found in our older pianos. (Once drawn wire was introduced, and the gray iron plate was developed to support the higher tensions possible with this wire, piano designers went crazy!) Over the years I’ve been taking another look at lower tension scaling and, increasingly, I’m liking what I’m hearing.

Del

Del,

I recently discussed my first experience going to a concert played on a fortepiano at the University of Washington. I was pretty blown away by the instrument and lamented about how loud the modern piano has become. I found the fortepiano concert to be one of the most gratifying musical experiences that I have been to. These instruments seem so much more personal than a modern piano, and so much more expressive. I especially like the sound produced by the leather hammers, kind of zingy. What was most interesting to me was that you could hear the pianist breathing while he played. I really felt like I was sharing the experience of the music with the performer, as opposed to observing a musician pounding away at a giant black beast.

I have thought alot since then about the potential of pianos to return to their smaller simpler roots. It seems to me if you got rid of the big tight strings you could eliminate the massive iron frame and alot of the supporting wood work. Maybe the frame would be steel or some type of unified body construction using steel extrusions. Who knows. I like the reliability of the modern piano and I think you could easily keep those good improvements while returning the sound and structure back to its genesis a little bit. I'd buy one.

Kirk

Del,
Great post Del. Chopin would agree I think, he said once that real music can't be made outside of the drawing room. Liszt might have felt differently though.

I think there are other reasons why we have gone to a more brilliant sound in this culture, and it's not just limited to pianos, but that's another discussion

Dan

Thank you, Del for the free seminar. Very interesting to read what you are thinking. I loved the sound of the Walter grand, although I wound up buying an Estonia. Guess that makes me a low tension guy.

Del....what an asset to the Piano Forum.

There is a point at which the tension becomes so low that the volume really falls off. You can hear it near the break in pianos which have the hockey-stick shaped bridge. There seems to be a loss of harmonics there as well. Maybe you can design that out, but there must be qualities that are inherent to higher tensions. I guess there must be some limits.

Hi,
What's the deal with the hocky stick type bridges? I recall Del saying something about the Walter not having it, I think because of the logrithmic scaling. Why would a piano have or not have it, is it generally a good thing or not, and what effect does it have?

Dan

Well, it foreshortens the scale near the break. You can make the rest of the piano relatively longer. However, I find that there is a dramatic fall-off in the tension of the strings there, unless you change the gauge of the wires often. Which I have been doing lately.

Grotriman brought this topic over to the Tuner's area, and some rumored data has been posted there. Unfortunately, it can't be correct. Also, some rough measurements I made on a couple of concert grands (Steinway D, Yamaha CFIIIs) indicate that the tension on them may not be so high either. What I can see is that where manufacturers have paid some attention to scale tension (many did not), there is a desire to have most of the treble at about 160 lb. Shorter pianos tend to have the tension drop off in the tenor, longer pianos tend to have it increase, as one would expect.

BDB's point is well taken. This is one of the major shortcomings (no pun intended) of the traditional scaling techniques. One of the most glaring offenders, simply because it is so well known, is the Steinway B. It has an average tension in the 155 – 165 lb range through the middle tenor section but from B#-26 (with 155 lbs.) it drops down to 115 – 120 lbs at F-21. Regardless the voicer’s skill this is going to be audible. It can be made less bad and you can grow accustomed to it, but it will never be good. (Well, it can be made good but it requires the installation of a transition bridge.)

The problem, of course, is that the designers of these scales felt it necessary to place the bass/tenor transition relatively far down in the scale. As to exactly why they believed this was necessary is unclear. It was probably a holdover from the harpsichord and fortepiano days and their brass bass strings though this is just speculation on my part. As may be, the early piano scale designers were quite willing to develop a more-or-less log scale pattern down to the mid-tenor (higher or lower, depending on the length or height of the piano) but then found it necessary to foreshorten the scale to avoid running into the back, or bottom, of the piano. They seem to have given little thought to possibly extending the bass section up a bit.

Using a very broad sweep of the scaling brush pianos below six feet or so will work best with 30 – 32 unisons of wrapped strings. Pianos in the six foot to seven foot range will work best with 25 – 32 unisons of wrapped strings. Pianos above seven foot will best use 20 – 27 unisons of wrapped strings. All of these transition points will be dependent on the type of scaling desired, i.e., long or short and high tension or low tension.

The goal here is scaling uniformity. It is desirable that the strings, regardless of their type, develop approximately the same harmonic spectrum and power given a uniform hammer blow. You can (and usually should) drop a bit of unison tension when transitioning to the wrapped bichords, but it should be kept to no more than 10 – 20 percent. This is easily achieved by maintaining approximately uniform string tensions and this is best achieved through the use of a log scale and by keeping the length disparity between the last plain steel string unison and the first wrapped unison relatively small.

There are many factors that govern the physical transition between the plain steel strings and the wrapped bi-chord strings but, regardless the length of the piano, these can be worked out to maintain a reasonably uniform tonal transition between them. It can only be done, however, if the designer is free to place that transition where it is best suited for the overall length of the scale. This means maintaining a log sweep to the bridge down to the point where length becomes a problem and then making the transition regardless of tradition.

Del

One should never underestimate the cheapness of manufacturers. Wound strings are more expensive than plain strings!

It's ridiculous in some respects. Piano strings, even the wound ones, are dirt cheap compared to other stringed instruments.

That's speculation on my part!

I ran the B scale through a spreadsheet, and found for a uniform tension of 160 lb. per string, the note #21 speaking length would be about 67", which is not out of line for a 7' piano. Change it from #21 wire to #22, and it drops down to about 64".

What really shows up to me is that in order to get a uniform scale, you really should use half sizes of wire at the break, and you should change gauges often. Conversely, there's not much point in making a lot of changes of gauge in the high treble. Here's my confession: The last 5'-8" Knabe that I did ended up with the top 24 notes being all #14 wire! That meant that the entire top section and a few notes beyond were the same size wire. The results were good. It sounds fine and stays in tune well, even on being freshly strung. It allowed me to lower the tension in the middle of the piano, and got rid of most of the nasty inharmonics which you usually get in Knabes.

It may be speculation but it's not a far-fetched as some might think given today's economy.

When Samuel Wolfenden published the first edition of his book, "A Treatise on the Art of Pianoforte Construction" in 1916 World War One was raging and copper was at a premium. What little there was was going into land fill in France and Germany with little, if any, being available for piano bass strings. This, of course, drove up the price of copper world-wide, including the U.S. It created a large market for soft iron wire.

Del

Actually, with #21 wire and a target of 160 lbs. per string I come up with a string length of about 1630 mm, or 64.2" With a length of 1705 mm, or 67.1" I come up with 160 lbs. of tension using the original #20 wire.

In either case these are longer string lengths than I would want in any 7' piano I was designing.

Del