2017 was our 20th year online!

Welcome to the Piano World Piano Forums
Over 3 million posts about pianos, digital pianos, and all types of keyboard instruments.
Over 100,000 members from around the world.
Join the World's Largest Community of Piano Lovers (it's free)
It's Fun to Play the Piano ... Please Pass It On!

Shop our online store for music lovers
SEARCH
Piano Forums & Piano World
(ad)
Best of Piano Buyer
 Best of Piano Buyer
(ad)
Pianoteq
Steinway Spiro Layering
(ad)
Wessell Nickel & Gross
PianoForAll
Who's Online Now
59 members (c++, AlphaTerminus, BlakeOR, 36251, BlaisGuitars, accordeur, Beansparrow, 11 invisible), 590 guests, and 465 robots.
Key: Admin, Global Mod, Mod
(ad)
Estonia Pianos
Estonia Pianos
Previous Thread
Next Thread
Print Thread
Hop To
Page 1 of 5 1 2 3 4 5
Joined: Nov 2010
Posts: 90
P
Full Member
OP Offline
Full Member
P
Joined: Nov 2010
Posts: 90
In the short term, fluctuations in temperature can make the iron frame expand or contract, as well as the strings and the wood, slightly changing tensions and speaking lenghts. As the humidity along with temperature fluctuates, the wood expands and contracts also and this may slightly change the crown or the exact positioning of the bridges and termination points, but they are relatively minor and over the long term these fluctuations should average out.

The tuning pins shouldn't move at all just by themselves. I assume they would stay in the same position for decades in a piano with a healthy pinblock if they aren't touched?

What other factors are at play that cause pianos to go a semitone flat in a decade? The only other thing I can think of is that the strings stretch.

Is the stretching of the strings the only dominant factor that causes pianos to go out of tune in the long term?

(ad)
Piano & Music Accessories
piano accessories music gifts tuning and moving equipment
Joined: Feb 2002
Posts: 1,938
1000 Post Club Member
Offline
1000 Post Club Member
Joined: Feb 2002
Posts: 1,938
Wow, a semitone in only a decade?
I've seen some pianos (for example 1950s Baldwin Hamiltons) that hadn't been tuned in several years (I don't know if it was a decade or not) that were within a few cents or so of A-440.


Associate Member - Piano Technicians Guild
1950 (#144211) Baldwin Hamilton
1956 (#167714) Baldwin Hamilton
You can right-click my avatar for an option to view a larger version.
Joined: Nov 2010
Posts: 90
P
Full Member
OP Offline
Full Member
P
Joined: Nov 2010
Posts: 90
Yes maybe that is too fast, maybe it should be more like 2 decades, or one and a half. But I still have the same question.

Joined: Jan 2010
Posts: 551
P
500 Post Club Member
Offline
500 Post Club Member
P
Joined: Jan 2010
Posts: 551
Originally Posted by partistic
The tuning pins shouldn't move at all just by themselves. I assume they would stay in the same position for decades in a piano with a healthy pinblock if they aren't touched?


I would say this assumption is wrong. For a piano to go a semitone flat, the pins must move. If strings stretched that much under tension, then the strings wouldn't be suitable for use in pianos!

The healthier the pinblock, the less pins will move over time so the closer the piano will stay at pitch.

If conditions are absolutely stable, then I would assume that the pins would be very unlikely to move in a healthy pinblock. It is when conditions change, and the pinblock swells or shrinks in relation to the pins, then the pins might make small, jerky movements as the interference fit is reduced.

Living in a room with a piano, one can occasionally hear this movement. A quiet 'ping' as a pin suddenly moves.

Joined: Jun 2003
Posts: 29,698
B
BDB Offline
Yikes! 10000 Post Club Member
Offline
Yikes! 10000 Post Club Member
B
Joined: Jun 2003
Posts: 29,698
Gremlins! They give stronger formulas of Grem-B-Gonâ„¢ to better tuners.


Semipro Tech
Joined: Jun 2011
Posts: 824
M
500 Post Club Member
Offline
500 Post Club Member
M
Joined: Jun 2011
Posts: 824

Pianos can easily drop as much as a sem-tone, especially when they are not looked after from new. Many manufacturers don't put the work into stretching the strings and bedding everything down now, before they release them for sale. New pianos need tuning much more regularly if they are to remain at concert pitch. On average I would guess that normally it's not until a piano is 2 - 3 years old that the pitch (as far as the strings stretching go that is) stabilises.

After that, I would say that the biggest change of pitch is firmly down to variation in humidity. If the soundboard absorbs moisture the crown increases and the tuning often goes wildly sharp .... the middle being the worst affected where the crown is greatest. On the other hand, dry the soundboard out and you get a wild drop in pitch. If you want a piano that is stable at concert pitch, then have it tuned evry 3 or 4 months for the first few years and keep the humidity constant so that the soundboard isn't constantly changing it's crown.


Concert Tuner & Technician for the past 52 years in the United Kingdom
www.jphillipspianoservices.freeindex.co.uk : E-mail jophillips06@aol.com
Joined: Jun 2010
Posts: 2,671
L
2000 Post Club Member
Offline
2000 Post Club Member
L
Joined: Jun 2010
Posts: 2,671
Originally Posted by Phil D
Originally Posted by partistic
The tuning pins shouldn't move at all just by themselves. I assume they would stay in the same position for decades in a piano with a healthy pinblock if they aren't touched?


I would say this assumption is wrong. For a piano to go a semitone flat, the pins must move. If strings stretched that much under tension, then the strings wouldn't be suitable for use in pianos!

The healthier the pinblock, the less pins will move over time so the closer the piano will stay at pitch.

If conditions are absolutely stable, then I would assume that the pins would be very unlikely to move in a healthy pinblock. It is when conditions change, and the pinblock swells or shrinks in relation to the pins, then the pins might make small, jerky movements as the interference fit is reduced.

Living in a room with a piano, one can occasionally hear this movement. A quiet 'ping' as a pin suddenly moves.


I disagree. A brand new piano left untuned will go 1/2 tone flat in a few years without any tuning pins moving. Moving pins will certainly lead to multi-note unisions, a tell-tale sign. Old pianos that haven't been tuned for decades will also go 1/2 tone flat or more without tuning pins slipping. Pin slipping is only happening in pianos with pinblock problems, etc.

In general, pianos go out of tune because of expansion/contraction of the plate, soundboard, and wire, not because of pin movement.


DiGiorgi Piano Service
http://www.digiorgipiano.com
Joined: Nov 2010
Posts: 90
P
Full Member
OP Offline
Full Member
P
Joined: Nov 2010
Posts: 90
If the speaking length of the string is roughly the same as the speaking length of a guitar string (around 60 cm?), then to change it's pitch by a semitone, the speaking length should change by roughly as much as the distance to the first fret. This is something like 3,5 cm. I cannot imagine the plate and the termination points warping so much, or do they?

Are we left with the explanation of the strings stretching or are there other possibilities?

Joined: Apr 2010
Posts: 2,281
K
Platinum Subscriber
2000 Post Club Member
Offline
Platinum Subscriber
2000 Post Club Member
K
Joined: Apr 2010
Posts: 2,281
The short answer to the topic is . . .

Why not??

But here's a longer answer. . . wink

"Should average out" is the main unsupported leap of assumption in this post. You have up to 40000 pounds of tension pulling in one (OK, two) directions and exerting pressure in a perpendicular plane, as well. And random fluctuations are supposed to average with no change given a huge force in one direction?

Think of it this way. . .

You are on a very steep slope composed of sand and gravel-- just short of the steepness required for a landslide to happen. Now, let's suppose you occasionally step down but also step up but your main direction of travel is sideways across the face of the slope. Will the "average" result in a path straight across the face of the slope?

No way. Gravity is working on everything and it exerts a constant downward force on you, the gravel, your shoes, and the pack on your back. If you assume a directly sideways direction across the face of this slope, your path in the sand will show that you are, in fact, trending downward. Every step you take results in a downward component -- even the ones where you step upwards.

Or, think of a huge tanker ship that is headed from Seattle to Japan. But, there's a 25 horse outboard motor on the bow which is aimed sideways to the right (starboard, if you're nautical). That ship will not arrive in Japan, but more likely Shanghai or Singapore.

When you have forces in random directions added together with a force in a consistent direction, the average must always be in the direction of the consistent force. So, what would be surprising is a piano (or any other string instrument) that didn't trend downward in pitch over time.

But wait, there's more. smile

You have at least 210 strings on 88 notes. Never mind what I just pointed out above. With all of this random movement, how could you think that all 210 of these strings are going to ever return at any point to exactly the same relationship with each other that they started out with? That's like putting 210 unsecured boxes in the back of a truck in a nice regular pattern and driving over a bumpy road. After a while you notice that these boxes are no longer in the same position as when you started. Do you really think that further driving over a randomly bumpy road will normally return those boxes to their original position?

Oh, and by the way, it's an open flat bed truck. How are the boxes that get bounced off going to come back? In a piano, you also may have random tuning pin tightness (and/or other factors, some of which are not well identified). So some amount of fluctuation may just put it beyond that pin/string's ability to hold.

It's kind of like asking why people die when the real question is how are we able to stay alive. Our normal bodily functions are an amazing miracle that shouldn't really happen. In the same way, a piano is inherently instable. It's amazing that the thing stays in tune at all -- and sometimes for months (and, in rare cases, years) at a time.


Keith Akins, RPT
Piano Technologist
USA Distributor for Isaac Cadenza hammers and Profundo Bass Strings
Supporting Piano Owners D-I-Y piano tuning and repair
editor emeritus of Piano Technicians Journal
Joined: Feb 2002
Posts: 1,938
1000 Post Club Member
Offline
1000 Post Club Member
Joined: Feb 2002
Posts: 1,938
So has anyone ever done any testing to try to figure this out?

For example, maybe take a 20- to 50-year-old Baldwin piano (old enough so the new piano instability is gone, it's not sourced from overseas (and was built before Baldwin's domestic quality had started to go down, from what I understand) and the soundboard has settled down from its wild fluctuations when new, but not so old that the pinblock is beginning to be compromised or the bridges are starting to crack) somewhere in a stable (climate) part of the southwestern USA that has lived there all its life. Have a good technician (preferably one who passed, with a perfect score, the exam to become a CTE) tune the piano carefully and make sure it's as solid & stable as s/he can get it. Also if desired, a DC system could be installed in the piano.
Then, periodically measure things like temperature, humidity, pitch of individual strings, moisture content of soundboard & bridges, etc, until the piano has naturally sunk to a full step flat (A sounding like G).

I wonder what that would tell us about piano pitch behavior over time, and why it goes flat?


Associate Member - Piano Technicians Guild
1950 (#144211) Baldwin Hamilton
1956 (#167714) Baldwin Hamilton
You can right-click my avatar for an option to view a larger version.
Joined: Jun 2011
Posts: 3,043
3000 Post Club Member
Offline
3000 Post Club Member
Joined: Jun 2011
Posts: 3,043
Originally Posted by Phil D
[quote=partistic]The tuning pins shouldn't move at all just by themselves. I assume they would stay in the same position for decades in a piano with a healthy pinblock if they aren't touched?




The healthier the pinblock, the less pins will move over time so the closer the piano will stay at pitch.
/quote]
I agree Phil D too.

Joined: Jun 2010
Posts: 2,671
L
2000 Post Club Member
Offline
2000 Post Club Member
L
Joined: Jun 2010
Posts: 2,671
Originally Posted by Maximillyan
Originally Posted by Phil D
[quote=partistic]The tuning pins shouldn't move at all just by themselves. I assume they would stay in the same position for decades in a piano with a healthy pinblock if they aren't touched?




The healthier the pinblock, the less pins will move over time so the closer the piano will stay at pitch.
/quote]
I agree Phil D too.


If pianos went out of tune because the pins move, you'd be correct. Unfortunately.....


DiGiorgi Piano Service
http://www.digiorgipiano.com
Joined: Nov 2010
Posts: 90
P
Full Member
OP Offline
Full Member
P
Joined: Nov 2010
Posts: 90
My family has a piano that wasn't tuned for 40 years. It was over a whole tone flat, even more in the treble. The plate would have to be very seriously warped and distorted to account for a significant proportion of that flatness, but it looks nice and straight to me. The plate is made of relatively brittle iron in my understanding and I don't think it can bend that much without cracking, or without any visible evidence.

If the bridge would move several cm due to the forces applied on it over decades, there would have to some serious cracks somewhere to make the movement possible.

The other possibilities I see are the tuning pins letting go and the strings stretching. It's probably hard to tell how significant each is, as it would require a long study on a deserted piano. It would be interesting if such a study would be made, where they exactly measure the strings for stretching, the tuning pins' positions and the exact speaking lengths to see how big of a role each has.

If the tuning pin needs 5 Nm of force to overcome friction, it isn't just going to come out of someplace someday and make the pin move. But then again, as the strings can creep and stretch, so should the wood grains around the pin?

Joined: Feb 2011
Posts: 3,224
W
3000 Post Club Member
Offline
3000 Post Club Member
W
Joined: Feb 2011
Posts: 3,224
Originally Posted by partistic
My family has a piano that wasn't tuned for 40 years.


Question. When a piano hasn't been tuned for many years can the pins become more difficult to move and is there a greater risk of damaging the block?

Ian


Ian Russell
Schiedmayer & Soehne, 1925 Model 14, 140cm
Ibach, 1905 F-IV, 235cm
Joined: Jan 2010
Posts: 551
P
500 Post Club Member
Offline
500 Post Club Member
P
Joined: Jan 2010
Posts: 551
Originally Posted by Loren D
Originally Posted by Phil D
Originally Posted by partistic
The tuning pins shouldn't move at all just by themselves. I assume they would stay in the same position for decades in a piano with a healthy pinblock if they aren't touched?


I would say this assumption is wrong. For a piano to go a semitone flat, the pins must move. If strings stretched that much under tension, then the strings wouldn't be suitable for use in pianos!

The healthier the pinblock, the less pins will move over time so the closer the piano will stay at pitch.

If conditions are absolutely stable, then I would assume that the pins would be very unlikely to move in a healthy pinblock. It is when conditions change, and the pinblock swells or shrinks in relation to the pins, then the pins might make small, jerky movements as the interference fit is reduced.

Living in a room with a piano, one can occasionally hear this movement. A quiet 'ping' as a pin suddenly moves.


I disagree. A brand new piano left untuned will go 1/2 tone flat in a few years without any tuning pins moving. Moving pins will certainly lead to multi-note unisions, a tell-tale sign. Old pianos that haven't been tuned for decades will also go 1/2 tone flat or more without tuning pins slipping. Pin slipping is only happening in pianos with pinblock problems, etc.

In general, pianos go out of tune because of expansion/contraction of the plate, soundboard, and wire, not because of pin movement.


You seem very sure. To my mind, if a piano goes out of tune purely by expansion and contraction, then surely it would average out over time, and so not result in a general drop in pitch.
How can you account for the reduced tension needed for the pitch to drop continually over time?

The strings stretching is the only other possibility, and yes, I'd imagine this could simply be the answer. But do strings continue to stretch under a constant tension? My physics isn't up to answering, nor can my experience give me an answer.

I would disagree that the pins moving would lead to multi-note unisons. This is the case when the pins are actually too loose to hold a tuning. But the movements I am imagining are tiny, micro-movements, of the same size as the smallest possible pin movement we can make as tuners.

I imagine the friction between the pin and its hole to be a lot greater than the rotating force on the pin produced by the tension on the string. This is necessary for a piano to stay in tune. But with changes in humidity, there will be sudden movements around this hole as the wood swells or shrinks, and has to take up a new position around the more solid pin. As there is a constant rotating force on the pin, I would say that as the hole moves, the pin will creep around in the direction of the force, lowering the pitch.

As I say, this is what I imagine could happen, and I have no evidence for this. But I am not so sure that pitch dropping can be explained just by string stretching alone in pianos which have reached their 'stable' period.

Does anyone have evidence to support or refute this assertion? I'd be really interested to know if anybody has researched this!

Joined: Feb 2002
Posts: 1,938
1000 Post Club Member
Offline
1000 Post Club Member
Joined: Feb 2002
Posts: 1,938
I mentioned above and will try to paraphrase here....

Has anyone ever thought about trying to find out what makes a piano go flat over time? For example, take a Baldwin piano (either a Hamilton or a mid-size grand like an L or SF10) in a place like CO, NM, UT, AZ, or parts of CA or NV that's lived there all its life and is old enough to have settled and the board to have lost some crown, but not so old the pinblock is starting to go. (Optionally install a DC system, then) Have a few CTEs agree on the best tuning for that piano. Then, neglect tuning it until it's a full step ("A" sounds like G) or two ("A"=F) flat, periodically measuring the various things that are suspected to cause a piano to go out of tune.

So who's up for that project? laugh


Associate Member - Piano Technicians Guild
1950 (#144211) Baldwin Hamilton
1956 (#167714) Baldwin Hamilton
You can right-click my avatar for an option to view a larger version.
Joined: Nov 2008
Posts: 16
C
Junior Member
Offline
Junior Member
C
Joined: Nov 2008
Posts: 16
There are three main enemies of piano health:

1) Humidity Swings
2) Lack of Professional Service
3) Poor quality parts

If the home environment, equaled that of an environmentally controlled laboratory ~ the customer’s piano would rarely need tuning.

Without a doubt pianos with loose tuning pins will not hold tuning as well as pianos with tight tuning pins, but what caused the pins to loosen. I contend it was the humidity swinging back and forth that almost always causes pins to loosen.

On my website I have written four short articles dealing with "Humidity & Pianos" I think every piano owner would benefit from reading them.

Last edited by Chuck Littau; 07/04/11 01:16 PM.

Chuck Littau, Kansas City Piano Tuner
Serving greater Kansas City since 1984
KansasCityPianoTuning.com
Joined: Nov 2010
Posts: 134
Full Member
Offline
Full Member
Joined: Nov 2010
Posts: 134
I think it is at least partly due to gentle string stretching. The reason I say this is because I tuned a small Kawaii grand that I had tuned a year prior. The interesting thing was that every time the string gauge changed the amount the string was off by a different amount. So if in the treble were the gauge stays the same for a time each note of a certain gauge was off on average the same amount. This was really just something I realized by ear since I do not use a device. The gauges were marked on the bridge instead of the plate which made it easier for me to correlate this. I think I will take a laptop and watch tunelab and get some numbers to see if I am right next time. I really don't know exactly what would cause this and I don't know if it is a common occurrence either. But I think it could be the difference in the gauges allows different stretch rates?


Daniel Bussell MPT
Mead Piano Works
East Tennessee

Joined: Jun 2010
Posts: 2,671
L
2000 Post Club Member
Offline
2000 Post Club Member
L
Joined: Jun 2010
Posts: 2,671
Any string under any amount of tension is in an unrelaxed state, which I would think would want to return to a relaxed state (would want to return to 0 tension). How much physics are required to think that 230 or so strings pulled to pounds and pounds of tension would, over time, stretch?

Did you ever tune a piano and come back a year later to find a bunch of unsions nearly clean, but 10 cents or so flat? Is it likely that all three strings of those unisons turned the precise amount necessary to have each string land so that the unison is nearly clean?

I guess if you want to conduct a 20-year experiment to be sure, that's fine, but isn't it pretty obvious that the strings are stretching?


DiGiorgi Piano Service
http://www.digiorgipiano.com
Joined: Jun 2003
Posts: 29,698
B
BDB Offline
Yikes! 10000 Post Club Member
Offline
Yikes! 10000 Post Club Member
B
Joined: Jun 2003
Posts: 29,698
Stretching is asymptotic. It happens a lot when the strings are new and very little thereafter. If the piano is not tuned enough at first, it will go way out of tune from stretching, but not otherwise. After 4 or 5 years, it is not a factor.

Keith's description of what is basically entropy is more likely to be the reason a well-tuned piano goes flat with time.

Around here, the weather is fairly constant all year long, and pianos can stay not just close to pitch, but close to tune for a long time, bad tuners and gremlins notwithstanding.


Semipro Tech
Page 1 of 5 1 2 3 4 5

Moderated by  Piano World 

Link Copied to Clipboard
(ad)
Faust Harrison Pianos
Faust Harrison 100+ Steinway pianos
(ad)
PianoDisc

PianoDisc
(ad)
Piano Life Saver - Dampp Chaser
Dampp Chaser Piano Life Saver
(ad)
Mason & Hamlin Pianos
New Topics - Multiple Forums
Lower Pianoteq power consumption
by meghdad - 06/23/21 11:18 AM
Opinion on Sherlock and Manning 13657
by JKyser - 06/23/21 09:39 AM
What a great book!
by Ubu - 06/23/21 09:03 AM
Piano out of tune after tuning
by Gashdal - 06/23/21 08:34 AM
Does Pianoteq benefit from more cores
by Christopher90 - 06/23/21 04:53 AM
Download Sheet Music
Virtual Sheet Music - Classical Sheet Music Downloads
Forum Statistics
Forums42
Topics207,667
Posts3,106,589
Members101,889
Most Online15,252
Mar 21st, 2010
Please Support Our Advertisers

Faust Harrison 100+ Steinways

Dampp Chaser Piano Life Saver

 Best of Piano Buyer

PianoTeq Bechstein
Visit our online store for gifts for music lovers

Virtual Sheet Music - Classical Sheet Music Downloads



 
Help keep the forums up and running with a donation, any amount is appreciated!
Or by becoming a Subscribing member! Thank-you.
Donate   Subscribe
 
Our Piano Related Classified Ads
| Dealers | Tuners | Lessons | Movers | Restorations | Pianos For Sale | Sell Your Piano |

Advertise on Piano World
| Subscribe | Piano World | PianoSupplies.com | Advertise on Piano World |
| |Contact | Privacy | Legal | About Us | Site Map | Free Newsletter | MapleStreetMusicShop.com - Our store in Cornish Maine


© copyright 1997 - 2021 Piano World ® all rights reserved
No part of this site may be reproduced without prior written permission
Powered by UBB.threads™ PHP Forum Software 7.7.5