A definitive (?) piece on string "stretching"

[fazool]

This is a topic that has been hotly debated (including vociferously by myself).

The recent thread about the life expectancy of guitar strings included a sidebar about pianos.

I thought "that is a great example of strings under tension that do not elongate". I figured I would make a post proving this and I found an online article by the Piano Technician's Guild called "How often should my piano be serviced?". In it they quote the world's experts on this topic. Here are their (abbreviated) quotes with my comments.

(In my comments I used the word elongation deliberately to avoid the slang term "stretch" which could simply mean tightening/settling string windings). I am referring to the permanent deformation of the metal by that term.

Originally Posted by (c) 1993 Piano Technicians Guild

Because your piano contains materials such as wood and felt, it is subject to change with climatic conditions. Extreme swings from hot to cold or dry to wet cause its materials to swell and contract, affecting tone, pitch, and action response or touch.

They only mention materials swelling and contracting due to climatic conditions. They do not mention metal elongation.

Originally Posted by Baldwin Piano Company (Chickering, Wurlitzer)

In the first year, the National Piano Manufacturers Association recommends that you have your piano tuned four times. This is a period of environmental adjustment for a new instrument, and proper attention is important. After the first year, the piano should be tuned at least twice each year, depending upon the frequency of use and atmospheric conditions.

They mention atmospheric conditions. They mention frequency of use but that refers to the wood and structure of the piano, not the metal elongating.

Originally Posted by Pearl River

Changes in temperature and humidity, the amount and type of use it gets, and the musical requirements of the owner will determine how often your Pearl River piano will need service.

Again, environmental discussions.

Originally Posted by Samick (Knabe, Kohler & Campbell, Conover Cable, Bechstein & Sohmer)

We recommend two to three tunings the first year and a minimum of two tunings per year thereafter. Avoid placing your piano where it will be exposed to extreme heat or cold, moisture, or direct sunlight, all of which can cause unstable tuning, warpage, and finish damage.

They specifically link environmental conditions to tuning instability

Originally Posted by Schimmel

As a rule, a brand new piano should, depending on its location and climatic conditions, be tuned two to three times in the first year or two.

Originally Posted by Steinway & Sons (Boston & Essex)

Unfortunately, no matter how expertly a piano is tuned, atmospheric variations and the nature of the piano's construction constantly conspire to bring it off pitch.

Probably the most powerful statement from the most respected name.

Originally Posted by Yamaha Pianos

New pianos should be tuned a minimum of four times the first year to compensate for the normal settling that takes place.

"settling" agrees with the others - the piano construction, not the string metal.

Originally Posted by Kawai Piano Company

Due to string stretching, settling, and the effects of climate, a new piano should receive at least four tunings in the first year.

This is where things go bad: they throw out a completely different idea

Originally Posted by Young Chang America, Inc.( Pramberger & Bergmann)

Piano owners will receive optimum performance from their piano if it is properly serviced during its lifetime to compensate for the effects of environmental conditions and use.
Due to the natural elasticity in new piano strings, we recommend that your instrument be tuned two to four times the first year, twice the second year and a minimum of once per year thereafter.

This one is downright wrong - they use the term "elasticity" completely wrong. Elastic movement is the opposite of permanent change/stretch/elongation. So they have zero credibility when they say this because they are speaking nonsense gibberish by making up phrases

So, what I see is that this is indicative of everything argued on the Internet: There is some good information out there from credible sources, but then other sources promote misinformation, which people falsely put credibility in.

If this were a "vote" it would be 6 votes not ascribing this to metal elongation, 1 vote ascribing it to metal elongation and 1 vote ascribing it to metal elongation then admitting they don't understand metal elongation.

There are so many lessons to be learned from all this but the most important one (I think) is this:

People and even big companies, especially on the Internet, that you believe can be wrong. Don't trust information just because someone said it with conviction. Use your head, logic, science and objective reasoning. If you can't reach a consensus, get more opinions and weigh them all. It is likely that the real answer will be very apparent to you and once you see that you will know to be more skeptical when some Internet expert spouts off.

One caveat to all this: aggressive playing will cause an elastic deformation of the strings (it will lengthen and shorten elastically). Some materials have a fatigue life where there are permanent metallurgical changes under this type of cyclic loading. Usually that results in localized work-hardening and then breakage but it can cause deformation, too. This is a very minor effect but I wanted to be technically accurate.

I am arguing mostly to explain that strings strung up to pitch don't just elongate under normal tension.

[Rodger Knox]

Originally Posted by fazool

I am arguing mostly to explain that strings strung up to pitch don't just elongate under normal tension.

That's correct in the context of guitar strings, but not necessarily true with an extended time frame. In a few hundred years, stress relaxation would cause enough elongation for a steel string to go a step or so flat. Same thing happens with all materials, it's just slower with some materials than others.

[Earl49]

Interesting that there are a number of engineers that are pretty active here (Roger, Fazool, Todd Yates, myself, and others).