Pitch change due to heat?

[Duncan Luddite]

My EC is showing a shift in tune from yesterday to this. Last evening my tuner was showing notes as having the expected tuning, but today they are all shifted approx. two notes along!
It’s summer here in Australia, and we’re currently at the in-laws house doing sorting and fire season prep. And it’s hot.

Last night, when things were a fair bit cooler, a ‘c’ was a ‘c’, etc, but today it’s an ‘e’, and a ‘d’ is an ‘f’, a ‘g’ an ‘a#’. They’ve all basically shifted a similar amount. But up. My understanding of metallurgy (from working on antique pocket watches) is that metal becomes softer with heat ( and a balance spring will not be as responsive and slow the parent watch down) not harder/tighter. 
Or am I perceiving it wrong and they’ve dropped down 6ish notes? Either way, it’s a big change. 
Will be checking it again this evening when is cooled down. 
Anyone else had this happen to this extent?

 

 

[Duncan Luddite]

OK, with a bit more of a check, every note is a one note and a semitone raised from last night, not dropped. My wife is wondering if it is due to the brass reed expanding and reducing the gap between it and the reed frame. 

Edited November 21 by Duncan Luddite
Missing word

[alex_holden]

That much change sounds very unlikely. Can you try measuring it with a different tuner?

[alex_holden]

Also, you could try playing this on loudspeaker and see if your tuner recognises it as A4 (440Hz):

 

[Duncan Luddite]

Interesting @alex_holden  I’m using Tonal Energy and it’s identifying the 440 hz A you linked as C, 439.7 hz! I have the tonal intervals set up as you and P. Hardy detailed back in the discussion on EC tuning. Somewhere a setting must have been changed. 
It’s set to A 440. Rummaging around the app.instructions time. 
Thanks very much for the link; it cleared up a huge worry for me

Cheers

[Duncan Luddite]

Hang on, Transposition A-3 was selected. Have set it to C 0 and it now identifies your tone as A.  And playing notes on the EC now make sense again
Thanks again. 

Edited November 21 by Duncan Luddite

[Duncan Luddite]

Tonal Energy has *so* many bells and whistles…….

[Richard Mellish]

One of the things that I find remarkable about free reeds is how stable their pitches are, apart from some variation with pressure, and some long-term drift. If a change of temperature within human-tolerable limits could cause three semitones change they would never have come into use.

[Duncan Luddite]

I was somewhat shocked at what ‘appeared’ to have happened  

 So nice to know they are much more robust. High temperatures is something Australia’s good at and , while I take precautions against the EC getting hot, knowing that 32degC indoors isn’t going to mess it up is a great relief.
The Jabez Austin is my first introduction into the world of the concertina ( and a very nice one at that), a world I wasn’t sure I’d ever be able to afford to enter. 
I wish to take great care of it. 

[Chris Ghent]

1 hour ago, Richard Mellish said:

One of the things that I find remarkable about free reeds is how stable their pitches are, apart from some variation with pressure

Is there any science on this..?

[alex_holden]

2 hours ago, Duncan Luddite said:

Hang on, Transposition A-3 was selected. Have set it to C 0 and it now identifies your tone as A.  And playing notes on the EC now make sense again

 

Ah right, that makes more sense. I never play with that setting.

[David Barnert]

Occam's razor: “The simplest explanation is usually the best one.” 

 

A piece of software behaving in an unexpected way is a much simpler explanation than an instrument full of free reeds going out of tune overnight by more than a few cents.

 

As soon as I read the initial post I predicted that the problem was in the tuner, not the reeds.

 

[Duncan Luddite]

10 hours ago, alex_holden said:

 

Ah right, that makes more sense. I never play with that setting.

I wasn’t Intending to either. I saw the ‘Transposition’ heading and tapped on it to see what it was ( I was wondering if it might show a musical stave or something   ), and then couldn’t work out how to reset it. I also thought you might have to do something else to activate it. Nope

 Learning so much. 
 Thanks again for your comments which got me looking in the right place.