List your top 5 reasons....

[ojkojbgoj]

a piano goes out of tune! Or the fancier version: what most affects tuning stability?

[robson]

most important factor - temperature change, then quality of pins, strings and pins mountings
as well as amount of play time put on piano.

[johnmar78]

best keep your piano in a controoled room temperature like Bosendofer did. 22 degrees. The tune should last for a long time.

[lhorwinkle]

Temperature is largely irrelevant.
Humidity is the major factor.
The amount of usage is another factor.

[robson]

Temperature is largely irrelevant.
Humidity is the major factor.
The amount of usage is another factor.

Temperature no, but temperatue changes yes.
Humidity has little to do with tune.

[iansinclair]

Just from my own experience -- I'm not a technician! -- I'd have to agree that temperature changes raise havoc with the tuning.  That would have to be number one.  The curious thing, though, in my experience, is that if the change is slow (in both directions), while the piano will be out of tune -- sometimes unplayably so -- after the change, once the change is undone the piano will be surprisingly close to where it started (my test case is a Steinway M which lives in an unheated studio at my place; it's tuned in the spring, when the weather warms up, and holds its tune right until the weather gets cold (below freezing) -- when it goes out.  But once spring comes again, it comes back in tune very nicely, and doesn't need much more work than if it had been in a heated space all winter).  Humidity does seem to affect tune (although it affects the action much more!) but it seems to me that this is more due to individual pins becoming slightly loose if it is too dry than it is to any overall effect.  Actually playing a piano doesn't seem to have much effect, provided the pins are tight -- although preparing a piano for some modern "prepared piano" pieces (a practice which, in my view, should be banned) can cause real tuning disasters, even if it doesn't actually lead to broken strings.

[hbofinger]

I play mine so much I basically need to tune it every two weeks or even more in terms of just maintaining. This is on a new pinblock. I ended up having to do the same on my previous piano. I do it myself now. So if you use it a lot, you will also bang it out of tune, especially if you play at volume. Not necessarily the temperament itself, but unisons will go first. After a while it gets so bad you have to reset the temperament, because the one string in a unison that may be right varies from note to note!

Ever notice how in real concerts during intermission there is a tuner at the piano fixing whatever mess the performer has created while banging on the keys?

[robson]

Ever notice how in real concerts during intermission there is a tuner at the piano fixing whatever mess the performer has created while banging on the keys?

yeah, I have noticed that! I don't get why some players are so messy???  


p.s.
so you got to have old piano if you need to tune so often?

[johnmar78]

this is what i found, on a cold day, my piano has higher crystal clear sound, on a warmer day you have a warmer rounded sound. Why? this is due to expension of strings as cause by teh temerature chane so as the sound board. Too much humidity would be a serious problem to string rust.

[lhorwinkle]

Repeat ... temperature has little affect on tuning, save for extreme changes in temperature ... such as moving a piano out into the sunlight. But who does that?

What you think is a temperature-induced tuning shift is generally a humidity-induced shift.

As for the piano sounding different with temperature ... the temp affects our hearing perception. Bass sounds become more prominent in warm temperatures. This is not a change in the source. This is a change in the listener. (I don't know why, though.)

[silverwoodpianos]

Repeat ... temperature has little affect on tuning, save for extreme changes in temperature ... such as moving a piano out into the sunlight. But who does that?

This part is accurate; humidity changes will have a more noticeable effect on the rise and fall of the sounding board and other frameworks that make up the construction of a piano.

What you think is a temperature-induced tuning shift is generally a humidity-induced shift.

Perhaps in some circumstances but not a presumption for all cases.
 

As for the piano sounding different with temperature ... the temp affects our hearing perception. Bass sounds become more prominent in warm temperatures. This is not a change in the source. This is a change in the listener. (I don't know why, though.)

Consider this; sound travels at 1132 feet per second at 32°F. For every degree in temperature rise add 30 feet per second.

[johnmar78]

Repeat ... temperature has little affect on tuning, save for extreme changes in temperature ... such as moving a piano out into the sunlight. But who does that?

What you think is a temperature-induced tuning shift is generally a humidity-induced shift.

As for the piano sounding different with temperature ... the temp affects our hearing perception. Bass sounds become more prominent in warm temperatures. This is not a change in the source. This is a change in the listener. (I don't know why, though.)

that is interesting, i must to a recording experiment in cold morning vs hot day....

[robson]

repeat - changes in temperature have the biggest influence on piano being in tune, it's physics alright?  Regarding humidity it affect tone color not pitch plus of course wooden parts of the piano.
Sound travels in the air so the thickest are (more humid) the more mellow the sound and has nothing to do with the listener.

[silverwoodpianos]

repeat - changes in temperature have the biggest influence on piano being in tune, it's physics alright?  Regarding humidity it affect tone color not pitch plus of course wooden parts of the piano.
Sound travels in the air so the thickest are (more humid) the more mellow the sound and has nothing to do with the listener.

Been a technician for 39 years and humidity changes have far more effect on the wooden structure of a piano than the temperature contraction/expansion of metal wire. Humidity or humidity release in the sounding board will cause it to heave or slump depending upon what condition the instrument finds itself subjected to.

Here is a posting from my blog about humidity experiments done by myself and a colleague last year.
Photo set at the bottom of blog posting. Happy reading….

https://silverwoodpianos.blogspot.ca/2011/04/humidity-and-piano-sounding-board.html

[lhorwinkle]

Good info, Dan. Thanks.

BTW, I think your air speed calculations are a bit off. Yes, a bit over 1000 ft/sec at ordinary temperatures. But the variation is far less than 30 ft/sec/degree. It's just under 2 ft/sec/degree C or just over 1 ft/sec/degree F. (source: Wikipedia)

[hbofinger]

yeah, I have noticed that! I don't get why some players are so messy???  


p.s.
so you got to have old piano if you need to tune so often?

I don't mean setting the temperament. It's just having unisons perfect.

The pinblock is brand new. I currently own a Yamaha C7. My previous instrument was a model 200 Bösendorfer (it was just a couple of years old when I bought it). Playing the piano heavily will definitely also affect its tune.

[johnmar78]

Hey Silverwood, Lucky I have had a dehumfier bar in my paino, but never used, since Sydney's weatehr is pretty dry as compared to other Asian regions.
In your experiment, have your tried "sealed the timber inside(sound board) with clear varnish". I was thinking this will stop any moistures getting absorbed in the sound board if not , I reckon 90% should be achieved at least. Do you think this would solve all "out of tune " problems, excluding loose spring pins. What you guys think??(everyone)