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Author: Paul Aviles
Date: 2024-02-05 07:08
I play "the plastic reeds" on a small opening mouthpiece with a relatively short lay. I have become aware of how badly my playing is affected by LOW air pressure or rather negative differential per hour, particularly when the relative humidity is LOW.
I am really interested in WHY there would be such a correlation rather than the problem itself. The interweb tells me that humidity actually makes air LESS dense. So why would MORE humidity seem to help me (which it does!)? The explanation for the lower density is that when molecules of water replace the space usually taken up by nitrogen and oxygen molecules, the water molecules are actually lighter. But if lower air pressure (or lowerING air pressure) is bad for me (the reeds need to be softer), then why wouldn't lower humidity be better?
Can it be that even though water vapor is LESS DENSE it still represents something "solid" that helps wag the reed?
Any brain storming would be helpful.
............Paul Aviles (caught in a lower pressure zone)
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Author: Julian ibiza
Date: 2024-02-05 12:12
Perhaps this is missing something, but I believe the reason why our lungs don't dry out when we breathe dry air, is because they saturate the air in that breath to its limit as relating to the temperature within them.Hence the humidity in our exhaled breath is a body temperature related constant, only that when we inhale moist air, our lungs need to supplement that humidity level less.
I think that's how it works but I'd be happy to stand corrected. I like these sorts of questions and expanding my grasp of them.( In preparation of things my kids ask me ! LOL)
Julian Griffiths
Tel. 34 696 798 853
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Author: Paul Aviles
Date: 2024-02-05 15:25
I left out a lot but let me expand a bit or rather, back up.
We know (some of us) that at higher altitude (such as Denver Colorado) the air pressure is different, lower. That has several effects. Water boils faster, so one needs to leave an egg in water longer to cook. Another effect is that with "thinner air," (less molecules per unit of volume) aircraft need a longer runway to take off.......a very real world problem indeed. AND clarinetists need to switch to a softer reed than they would use at sea level.
Now, air pressure (barometric pressure) can swing to a fair degree based on the weather. Usually when it is sunny and warm, the air pressure is higher(er). When the weather is cold and wet, the air pressure is low(er).
Recently (this is another odd problem that I have......it seems more prominent than in years past) I find while playing Legere reeds that there IS a weather related (air pressure related) issue. With all the "bad weather" we've had in the south central US, I find I have to seek out reeds that are from one quarter strength weaker to a full half strength weaker.
I only seek to understand WHY when you add the humidity factor there is either greater (when dry) or lesser (when humid) tendency for the reeds to respond as described. On the face of it, this seems backwards.
For the record, air is LESS dense when the relative humidity is higher.
I am convinced that cane players probably don't have the "air pressure" sesitivity issue to as much a degree because cane is more "flexible" and simply pressing a bit more on the reed makes it play like a softer reed (or rather allows you to play as if your mouthpiece has a smaller tip opening).
...............Paul Aviles
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Author: Hunter_100
Date: 2024-02-05 17:11
Many polymer materials absorb and release water when the humidity changes. The absorbed water has an effect on mechanical properties such as stiffness. I don't know the specifics of Legere's polymer blend but I would guess this is a possible factor.
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Author: lydian
Date: 2024-02-05 18:16
Legere is some sort of urethane. Zero moisture absorption capability.
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Author: Julian ibiza
Date: 2024-02-05 18:45
My apologies!
Apparently the levels of humidity in exhaled bread DO vary quite considerably, but I can't ascertain to what extent this is related to atmospheric humidity levels.
Anyway..... It looks like Hunter may well be on right track here.
Julian Griffiths
Tel. 34 696 798 853
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Author: Hunter_100
Date: 2024-02-05 19:25
Lydian, thanks for pointing out the legere reeds are polyurethane based. I was able to find this article describing the effects of humidity on urethane:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3176498/#R15
They find that the urethane in their study absorbs up to 8% water after exposure to high humidity environments. The effects occur in about 12-24 hours of exposure and are reversible in 12-24 hours after changing humidity again. This all seems to make sense to me...BUT the change in stiffness is opposite what Paul describes. The urethane in this study got softer with increase in humidity which would suggest a harder clarinet reed is required in humid environments. However Paul also stated that the humid/low density air by itself (no reed effect) requires a softer reed anyway because the air can't get the reed vibrating as easily.
I submit that there are too possible competing forces going on: The legere reeds soften when exposed to high humidity but because more air pressure is needed with high humidity, the player may or may not feel the effects and two effects may balance each other out.
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Author: Julian ibiza
Date: 2024-02-05 20:06
Hunter,
Why is more air pressure needed with high humidity?.... just curious!
Julian Griffiths
Tel. 34 696 798 853
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Author: lydian
Date: 2024-02-05 20:08
Interesting, but Legere doesn’t change at all in different atmospheric conditions. It barely changes in boiling water. Temperature and humidity can affect intonation though. The human mind can change quite a bit as well due to expectations and beliefs. The belief that the weather can affect a piece of plastic is a great example.
EDIT: I was mistaken about the material. It’s polypropylene which has a water absorption rate of 0.03% w/w, in other words, zero.
EDIT2: Humidity and weather is a red herring. The lower atmospheric pressure at high elevations does indeed affect the differential pressure needed to make the reed vibrate. With less back pressure in the instrument at high elevations, you either have to increase the flow rate or use a softer reed that will vibrate at the lower flow rate.
Post Edited (2024-02-05 20:30)
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Author: Luuk ★2017
Date: 2024-02-05 20:09
Mr Aviles, what is your driver for changing reed strength? Intonation, sound, comfort, ...?
What is the problem you try to solve?
Regards,
Luuk
Philips Symphonic Band
The Netherlands
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Author: Hunter_100
Date: 2024-02-05 21:14
I disagree that humidity is a red herring. I play cane reeds not synthetic but if I change the humidity in my house, I can feel it in my instrument. Also, my reeds play different from the winter to the summer, and we have big changes in humidity here in the north, usually hot and sticky summers and super dry cold air in the winter.
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Author: lydian
Date: 2024-02-05 21:30
Same extremes where I live. Wood definitely needs to be treated differently depending on conditions. Plastic does not. I’ve been playing indoor and outdoor gigs in extreme conditions on cane and synthetic for close to 50 years. I know what the effects are and aren’t.
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Author: Paul Aviles
Date: 2024-02-05 21:43
So I think most are misreading the situation. The basic issue probably is best described by saying: someone just gave you a reed that is too hard for you. Would you just blow harder and be happy?
I understand that most of us don’t travel with a clarinet and run into the problem of extreme elevation changes.
I’ve further complicated this scenario with humidity as a variable……sorry. When I first noticed the reed strength problem I thought it was just barometric pressure. However there were times when the barometric pressure seemed adequate but there was still the ‘harder reed’ problem. At that point it seemed as though it was then just any time the pressure was headed down (you can Google barometric rate of change for your area if you’d like to track this yourself). Still it seemed a crap shoot predicting how my reeds would respond. It wasn’t until this last round of checking both barometric pressure change AND humidity, that I started to see a predictable pattern.
I stipulate the plastic reeds to take the cane absorption of moisture out of the equation. Also my small tolerances (small tip opening) perhaps exacerbate the problem.
In the end though I’d only like to know if anyone would know why the presence of water molecules in the air would make the reed vibrate more assuredly.
…………Paul Aviles
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Author: Julian ibiza
Date: 2024-02-05 22:31
Lydian,
I think you really nailed it with your last words regarding playing at altitude. Roundly and eloquently expressed.
Julian Griffiths
Tel. 34 696 798 853
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Author: Julian ibiza
Date: 2024-02-05 23:32
The only thing I can think of that might just explain what Paul is experiencing, is if water molecules in the air add to its density effecting wind force upon the reed and perhaps also likewise back pressure. Atmospheric pressure refers to the density of gas molecules as I understand it, but not the quantity of water molecules. Like I said, I was wrong that exhaled breath maintains a relatively constant level of humidity, so one would expect an exhaled breath of damp inhaled air to be denser in water molecules than a dryer one. Hence a denser molecular soup bombarding the reed.
I don't know if that fits the way in which Paul is finding his playing affected, but it's all I can come up with by way of offering air humidity as potentially influential.
I don't think NASA is going to be headhunting me over this one!
Julian Griffiths
Tel. 34 696 798 853
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Author: lydian
Date: 2024-02-06 00:14
Humid air is less dense than dry air, the opposite of your intuition. Humidity would amplify the affect of high elevation.
My advice is learn to be flexible as a player so you can adapt to these miniscule effects.
https://www.engineeringtoolbox.com/density-air-d_680.html
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Author: Dan Shusta
Date: 2024-02-06 00:46
Paul stated:
"For the record, air is LESS dense when the relative humidity is higher."
I'm not so sure...I believe it all depends upon how you define "relative humidity". If, as a vapor, a steam, or a mist, then, yes, your statement may be true. However, if there are actual "water droplets" in the air, then your statement is most likely false, because the "water droplets" actually "increase" the density of the air.
You also stated:
"In the end though I’d only like to know if anyone would know why the presence of water molecules in the air would make the reed vibrate more assuredly."
Now, here, I equate "water molecules" as being equal to "water droplets", and as I stated above, the water droplets actually "increase" the density of the air.
All of the above I gleaned from the following article, https://www.thoughtco.com/chemical-composition-of-air-604288 under the section entitled Water Vapor in the Atmosphere, is the following:
"Although this CRC table does not list water vapor (H2O), air can contain as much as 5% water vapor, more commonly ranging from 1-3%. The 1-5% range places water vapor as the third most common gas (which alters the other percentages accordingly). Water content varies according to air temperature. Dry air is denser than humid air. However, sometimes humid air contains actual water droplets, which can make it more dense than humid air that only contains water vapor."
I'm not sure this answers your "assuredly" question, however, I hope it does.
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Author: Mark Charette
Date: 2024-02-06 01:03
Dan Shusta wrote:
> I'm not so sure...I believe it all depends upon how you define
> "relative humidity". If, as a vapor, a steam, or a mist, then,
> yes, your statement may be true.
Is true, not maybe true. As a vapor, the only thing that actually constitutes humidity. Mist, droplets, no. Steam - at 212 at sea level, yes. Superheated, no.
Relative humidity measure how much water vapor is in the air vs. how much it could actually contain, meaning 0% RH is as dry as air could be, 100% meaning no more vapor is possible to add - at the current temperature of the air.
How it affects a reed, which plays in a regime close to 100% humidity - probably not at all. BUT there are physiological events that change with humidity. I just spent the weekend in an area only 1000 ft higher than my normal elevation of 5000 ft, and my skin is suffering from the short-term drying effects.
I know something about water by studying water chemistry for a few years studying/operating pressurized water reactors.
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Author: Hunter_100
Date: 2024-02-06 02:32
Dan I think you are mixing up clouds vs humidity. Clouds are indeed droplets of water suspended in the air which is why you can see them. Humidity is dispersed molecules of water in air, you cannot see those.
Adding water to air lowers density because a water molecule have less mass than N2 and O2 molecules that make up the bulk of air.
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Author: Dan Shusta
Date: 2024-02-06 05:57
Thanks Mark and Hunter for edifying me. Much appreciated.
So, did Paul actually answer his own question? With humid air being "lighter" due to the decrease in mass density of water molecules, doesn't it make sense that lighter air would simply oscillate with greater ease in the clarinet cylinder and therefore require less input energy from the player to begin and maintain this oscillation?
Or, am I confused again?
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Author: lydian
Date: 2024-02-06 06:42
Since Paul is the only person on earth who notices this difference, something beyond physics may be at play here.
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Author: Paul Aviles
Date: 2024-02-06 06:43
The lower air pressure (atmospheric) causes whatever you are doing with air to be more difficult - hence the need for a softer reed. The question is still why moisture that makes air less dense cause the same effect as HIGHER atmospheric pressure. But I’ll just assume the presence of more molecules whatever they are will aid moving things with air - more bang for the buck.
………..Paul Aviles
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Author: Julian ibiza
Date: 2024-02-06 11:05
My point was that atmospheric pressure is the head count of gas molecules within a given volume of air, but does not include the molecular density in said volume of air by the additional water molecules that have displaced the gas molecules.
Presumably one kind of molecule is as good as any other for bombarding a reed so it vibrates........ or is it? ..Has anybody tried playing with a lung full of Helium?
( WARNING: For playing altissimo only ..LOL)
I found one study that claimed that air humidity tends to reduce wind speed velocity, which sort of suggests an increase in the combined gas and water molecular density , and another thing which stated that aircraft did not meet with additional drag when passing through clouds ( but that's water vapor!).
All in all I would suspect that the influences of air humidity on woodwind playing are a bit of a " The Princes and the pea" thing , and likely of a significance well below that of the atmospheric pressure effects which we have already established.
Julian Griffiths
Tel. 34 696 798 853
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Author: kdk
Date: 2024-02-06 18:20
It may be that focusing on how the reed itself performs under varying atmospheric conditions confounds the issue and that the conditions surrounding the reed have little to no effect. The explanation may have more to do with how easily sound waves move through the air. Water is a better sound conductor than dry air. Humid air should conduct sound more efficiently than dry air.
Some, I think a great deal, of a player's judgment (and all of a listener's perception) of a reed's quality of play is based on the result he hears. Most of what you hear as a player is conducted to your ears by the air between your instrument and your ears. Some of what you hear comes from acoustic effects of your playing environment. Bone conduction plays much less a part unless you plug your ears. So how much of the difference that you *feel* is actually a difference in what you *hear* aurally, which is much more likely to be affected by air density and relative humidity?
Karl
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