Temperature and pitch

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bigsciota
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Temperature and pitch

Post by bigsciota »

paddler wrote: Thu Sep 01, 2022 1:58 pm The differences in pitch and tuning between British and American flutes also has an interesting background based in the way concert pitch evolved in the separate locations. It is
almost by chance that we enjoy American flutes with decent A=440 hz tuning. Apparently, while Britain was racing upwards through pitch standards peaking at British High Pitch,
Americans (being anti-British at the time) opted for the French diapason normal standard (A=435 hz). However, that French standard was initially specified at a temperature of 59 degrees F.
American flute makers found that, at more normal temperatures, their flutes played at a higher pitch. In fact A = 435 at 59 degrees ends up being very close to A=440 at 70 degrees.
Lucky us! :D
This is a quote from paddler in the McKenna thread, but I figured this question would be much too thread-drifty to ask there.

I know the general basics of temperature and pitch for whistles and flutes, the idea that warmer=higher, colder=lower. However, it never really occurred to me until a recent very hot streak in my area this summer that I don't exactly know what temperature we're talking about exactly. Our body temperature is supposedly roughly 98.6 degrees F (37C). Presumably the air coming out of us is at a similar temperature. The instrument we're holding is going to be at roughly the ambient temperature of the room it's sitting in, provided it's been sitting there for a long enough time. As we play it, blowing hot air into the flute, it will warm up.

So, the question is, what temperature are we measuring exactly? The temperature of the air itself inside the flute, which is north of 90 degrees F? The ambient temperature of the room? The temperature of the body of the flute, which will stabilize at a sort of middle point between the two? My guess is the last one, since instruments will usually raise in pitch as they get warmer, despite neither the ambient temperature nor the temperature of my body changing much. But I don't quite know the physics behind it, so maybe someone can enlighten me. If I play in a cooler, even for enough time that my flute is as "warmed up" as it can be, will the pitch be inevitably flatter than if I was playing in a sauna? And can one of you science-minded flutemakers create a tuning slide that expands and contracts based on temperature so that my flute is always spot-on no matter how cold or warm it is? I expect royalties if you use that idea...
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Re: Temperature and pitch

Post by paddler »

Great questions!

As far as the physics aspect of this goes, the basic issue is that the speed of sound through air varies with the temperature of the air. The warmer the air, the faster sound waves travel through it.
When a flute generates a musical tone, sound waves are effectively bouncing back and forth within the bore, so it is the temperature of the air column within the bore that really determines
the pitch, and that will definitely vary based on the room temperature, even though the warmth of the player's breath will increase the temperature inside the bore to some extent.

But that doesn't totally answer your question, because what we would really need to know is what was meant/intended by the pitch standard. This, I think, you would have to look up
specifically in the standards document itself, where the standard was formally defined. I haven't chased this down, but it wouldn't surprise me if there was some inherent ambiguity in the specification
itself, in part because it is virtually impossible to pin everything down in such documents, and even if it was possible, it might not make much sense practically. So, my guess is that the specification
of temperature in pitch standards such as A=440 hz, refers to the ambient temperature of the room.

Flute makers aiming to produce a standards-compliant flute would then have to make some simplifying assumptions about uniformity of human body temperature (it is not uniform across individuals or within
an individual), the duration of warming up the flute, etc. Without pinning everything down, the standard would be under-specified. And in reality, many of these things would not be constant in practice.
Also, when performing in a room that is not at the standard temperature, all bets are off regarding any assumptions about playing "in tune" with others (at least to a high degree of precision without
player adaptation), given that different instruments respond in different ways to changes in room temperature, and potentially even in different directions in some cases!

Back to the physics part of this, there are some fun online calculators at the link below that let you type in the various temperatures and pitch frequencies you want to compare. You can try to determine
whether A = 435 hz at 59 degrees F is a higher or lower pitch standard than A = 440 hz at 70 F, for example.

http://www.sengpielaudio.com/calculator-pitchchange.htm
bigsciota
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Re: Temperature and pitch

Post by bigsciota »

paddler wrote: Thu Sep 01, 2022 9:47 pm Also, when performing in a room that is not at the standard temperature, all bets are off regarding any assumptions about playing "in tune" with others (at least to a high degree of precision without
player adaptation), given that different instruments respond in different ways to changes in room temperature, and potentially even in different directions in some cases!
Yes, a large part of my realization came when I was playing a bit on my little Dixon one-piece whistle, which is generally pitched correctly. However, we had a horrific heat wave this summer, and the ambient temperature in our non-air-conditioned apartment was hovering in the mid-80s for much of it. I noticed that the whistle was quite a decent bit sharp, and figured that the ambient temperature was to blame. Throwing it in the freezer did indeed flatten it tremendously, albeit temporarily. So that particularly whistle may not be suited to any session in the Sahara or the Arctic!
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Re: Temperature and pitch

Post by Jayhawk »

Playing in the States can be challenging with temperature differences! I've played gigs at 104 Fahrenheit outside...and in the sun, and I've played gigs outside when it was 42 Fahrenheit. While I can normally handle tuning adjustments just with my lip until the flute warms up, those extreme days are the reason I will always have a flute with a tuning slide...and my whistles have to be tunable as well.

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Re: Temperature and pitch

Post by Conical bore »

You know what's really frustrating about temperature and pitch? It's the moment you figure out that when playing flute along with a fiddler, our instruments "warm up" in two opposite directions!

When I start a practice routine at home with my fiddler Significant Other, my flute rises a bit in pitch as the air column warms up. Meanwhile, her fiddle drops a little in pitch as her fingers touch and warm up the steel strings, so they lengthen just the teeniest bit. We can start out in perfect pitch with each other, then after 10 or 15 minutes we've drifted far enough apart to sound sour. We have to stop and retune both instruments, then we're fine for an hour or two. Maybe if the ambient temperature was higher this wouldn't be as noticeable, but our music room is usually around 65 degrees F for most of the year, so the instruments start out fairly cool before being exposed to warm breath and warm fingers.

Two fiddlers playing together, or two flute players together wouldn't have this dissonance and might not even bother retuning, unless there was another pitch reference like a guitar player. The change in pitch would be moving in the same direction as they warm up the instruments. OTOH, fiddle and flute make a lovely sound together, and neither of us are about to change instruments at this point!
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Re: Temperature and pitch

Post by paddler »

And the tricky thing is that when you retune your flute by adjusting the tuning slide, this has more impact on the pitch of the
notes higher up the bore than it does on the notes lower down the bore, so you inevitably change the size of the intervals between
the notes. In other words, if the flute was in tune with itself before, it won't be in tune with itself once the tuning slide has been
adjusted to compensate for the temperature. With the new slide position it is as if you are now playing a new flute that is tuned
to a slightly different temperament. Your target note, say A, may be at the target frequency, but the other notes will not be at
their target frequencies (assuming all other factors remain unchanged).

This is one of the reasons why player adaptation is always essential in determining the actual pitch of each note. There is really no
such thing as a flute with perfect tuning, without the necessary dynamic adaptation from the player, no matter how much attention
the maker puts into tuning the flute to a specific pitch and temperament etc. It only really makes sense to talk about the tuning
of the flute and player combination ... over a certain range of temperatures.

I know this all sounds a bit picky, but we often get into discussions about certain notes on particular flutes being a few cents sharp
or flat, when the reality is that these other issues can have a larger impact than that, and are fundamentally unavoidable.
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Re: Temperature and pitch

Post by Jayhawk »

Good points Paddler...when playing with others, I've noticed that effect, too. We definitely are always playing our flutes into tune!

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Re: Temperature and pitch

Post by Conical bore »

paddler wrote: Sat Sep 03, 2022 12:12 am And the tricky thing is that when you retune your flute by adjusting the tuning slide, this has more impact on the pitch of the
notes higher up the bore than it does on the notes lower down the bore, so you inevitably change the size of the intervals between
the notes. In other words, if the flute was in tune with itself before, it won't be in tune with itself once the tuning slide has been
adjusted to compensate for the temperature. With the new slide position it is as if you are now playing a new flute that is tuned
to a slightly different temperament.
Good point. My Noy flute hits A440 when "cold" with the tuning slide completely closed, and I only have to pull it out about 1/4 inch after it warms up. So it's a change of intonation but at least not a major one, and it hits the 12TET intervals pretty close except for the F# at that position.

I've had other modern flutes that started out needing a bit of tuning slide extension to hit A440 and then needed more after warming up, which might have changed the intonation even more. Which I suppose could lead to some questions about where flute makers intend that slide to be used, and still hit best intonation on the flute? With the player being a variable of course. But do flute makers assume a bit of extension will always be used, and how much leeway do they allow on each side of the target position to sharpen or flatten the pitch?

Apparently on this Noy flute the maker intended minimal extension for an "average" player. Or else I blow more flat than average!
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Re: Temperature and pitch

Post by paddler »

Conical bore wrote: Sat Sep 03, 2022 1:00 pm Which I suppose could lead to some questions about where flute makers intend that slide to be used, and still hit best intonation on the flute? With the player being a variable of course. But do flute makers assume a bit of extension will always be used, and how much leeway do they allow on each side of the target position to sharpen or flatten the pitch?
I'm sure this varies among makers, but it doesn't make a lot of sense to make a flute with a tuning slide which is best in tune with itself,
and with its target pitch, with the slide closed, because then the slide can only be used to flatten the pitch or accommodate higher temperatures.
In my opinion, it makes more sense to target the flute's tuning such that its target pitch (say A=440 hz) is reached with the slide partially extended
(at least a few mm) at a standard temperature, and the flute is best in tune with itself (according to the intended temperament) at that slide
extension. When a flute is made this way, it can accommodate players who blow sharper or flatter than the maker, and it can be played at
warmer or colder temperatures than standard, albeit with slightly altered temperaments, and within a constrained range, of course.

I have had a lot of experience trying to reverse engineer this kind of issue with antique flutes. When evaluating an antique, I initially suspend any
assumptions about the intended target pitch, and simple play around with various tuning slide extensions until I find the point at which the
flute is best in tune with itself. I try to do this when the temp in my house is close to 70 degrees. Then I try to determine the target pitch by
adjusting the pitch calibration on my tuner to see what target pitch is needed for all of the flute's notes to be in tune without any kind of
trending toward sharper or flatter across the range ... all using the previously identified slide extension. This often also requires a lot of experimentation
with stopper positioning.

Using this method, I generally find that makers of antique flutes intended their flutes to be played with a substantial amount of tuning slide extension,
often somewhere between 10 mm and 25 mm. It is common to see British flutes that appear to have had their heads shortened to enable them to be
played at British High Pitch (A=452.4 hz at 60 F) with the slide closed, but where the rest of the flute was clearly designed to play at a pitch closer to
A=440 hz. In other words, such flutes are best in tune with themselves when the tuning slide is extended almost fully. It is one of the reasons people
have so much success with having new heads made for antique British flutes. A longer head negates the need for such a long tuning slide extension, and
also removes the large cavity in the bore profile caused by extending the slide. Most American flutes don't seem to exhibit this feature (flaw?), and
require a slide extension of around 10 mm or so, allowing the flute to be sharpened or flattened from its target pitch.
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Re: Temperature and pitch

Post by Terry McGee »

Sorry to be so late joining this conversation. It's Spring here, and several years of La Niña weather pattern have weaponised the weeds. And some guy came and bought one of my flutes in stock, so now I have to make a replacement. So inconsiderate! But enough with the excuses....

Paddler's point about a flute with one tuning slide being in tune at one extension only reminded me of this under-explained relic. In 1847 (just 101 years before I was born, so I remember it well), George Rose (yes, THAT Mr Rose) submitted a very famous Patent Application, "on behalf of a foreigner residing abroad". It was indeed the British Patent application to cover Boehm's newly invented cylindrical flute. But the drawing submitted showed two flutes, Boehm's and a more typical English style 8-key conical. But a conical with a difference. Where we expect to find a tenon and socket joint between head and LH, LH and RH, and RH and foot, there appears to be inserted a tuning slide. Three tuning slides? Here's the LH section showing two of them, the RH to Foot joint is similar:

Image

(You can see more at: http://www.mcgee-flutes.com/Rose1847patent.htm )

You can imagine when I first received the copy of the Patent and saw this second flute, I immediately scanned the associated document hoping for a full and expansive explanation. Tough luck!

Am I being fooled? Are these not tuning slides, but something else? Or had Rose also recognised that a single tuning slide cannot possibly permit a single flute to cover the range A430 to A453?

And the big question. Did he ever make one?
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Re: Temperature and pitch

Post by david_h »

Why is the top hole hole called the "d hole"? It's venting roll ?
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Re: Temperature and pitch

Post by Terry McGee »

Beats me too, david_h. And why is what looks like the usual upper C key hole labelled "additional hole for C natural"? And mentioned thus in the description:

"The third part of the invention consists in a method of strengthening or improving the note known as the middle C natural in ordinary flutes, which note is always very defeak [weak?] and defective. The method of effecting this object is by making an additional small vent hole near the d, or first hole, as seen in Fig 2, and which additional hole is furnished with a key, which is opened by the first finger of the left hand when C natural is required."

This sounds like our normal upper c key, apart from the fact that we operate that by the first finger of the right hand! Is it in any way related to the fact that the drawing is reversed and looks like a left handed flute?

I have heard it said that it wasn't uncommon to include misleading information in Patent Applications so as to confuse competitors. But this seems all a bit odd!
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Re: Temperature and pitch

Post by david_h »

Maybe Mr Rose had a specialist patent writer to do the work (as I believe is recommend now) and didn't proof read it.
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Re: Temperature and pitch

Post by Terry McGee »

It was even a bit weirder than that. It seems the Patent Applications could be put in in handwritten and hand-drawn form. The Patent Office subsequently engaged Messrs Eyre and Spottiswoode, "Printers to the Queen's most Excellent Majesty", to typeset, print and bind the official patent documents from that period. Malby and Sons did the lithography ("Printed on stone by..."). So this patent, lodged in 1847, was actually printed in 1856. I can't imagine that the printers or the lithographer would have called George in to discuss the finer details!
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Tell us something.: Ive played Irish Flute for a number of Years. Have played Sessions as well but not currently. I have also played Colonial American Flute in reenactment Groups. Started playing Clarinet in 1960 in School and later Community Bands. Also have played Bagpipes Solo as well as in Pipe Bands I played Drums in a Garage band in High School, probably my Instrument I played the best!

Re: Temperature and pitch

Post by Ben Shaffer »

1. Temperature

I played in Pipe Bands Years ago and a major problem was playing parades in the Winter. Lets say it was 40 degrees. You are marching and blowing hot air into the Pipes. The outside of the PIpes are cold, and presto when the 2 temperatures collided it could and did result in cracks in the Blowstick as well as drones.
So for the Pipes here it was the hot and Cold Tempatures colliding. So when you were standing around if the inside of the Pipes were cold it was not a big Issue, likewise in the Summer with the heat prior to tuning or playing.
2. Pitch
But in both cases as soon as you tuned up and played the Pitch was dramatically effected In the heat of summer of course the Pipes went up in Pitch dramatically, and then with the cold down
BTW most Pipes are Blackwood and if you had some Delrin PIpes to play outdoors in extreme temperatures that was great
Same goes for playing Clarinet with Pitch change
There may be some Pipers reading this and I'm sure they would be able to relate to this :poke:
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