Mouthpieces Mouthpiece resistance - how to measure it?

[Pete Thomas]

It occurred to me, people talk about more or less resistance due to tip opening and reed strength, but is there any scientific way to measure this?

Many people think there is a simple correlation between tip opening and/or reed strength and resistance.

Nononononono!

Well, only to a certain extent there can be a correlation, but this ignores other factors just as significant such as facing curve or chamber dimensions (not sure if quite as significant as tip or facing curve?)

This is understandable because people can grasp the concept of a top opening or a reed strength, but a facing curve is not so easy. And it can make all the difference, so for example a 8* on a PPT (see what I did there?) might correspond in resistance to a 7* on a Link. Between mouthpieces of the same brand and model it does make more sense, but not when speaking more generally.

Hence I'm wondering if it is possible for a super-clever resistance measuring device to be invented (or re-invented if it already exists)

 

[Dr G]

Perceived dynamic resistance could be measured as the change in pressure across the mouthpiece as a function of air flux. To do that, you need to measure air pressure on either side of the mouthpiece, and the airflow in the neck.

"Put in your earplugs, put on your eyeshades, you know where to put the cork..."

View: https://www.youtube.com/watch?v=ogHtl6UFSSI

 

[Jimmymack]

There must be a table out there somewhere indicating relative resistance to tip opening and facing curve. I bet Theo Wanne knows and other mouthpiece makers must have some idea at least I hope they do. If only there was one who posted here, oh, there is, come in Phil you’re needed.

 

[squeak]

Hence I'm wondering if it is possible for a super-clever resistance measuring device to be invented (or re-invented if it already exists)

In the most simplistic fashion, two identical balloons mounted on either side of the mouthpiece. You inflate one, open a valve and measure the time how long it takes for the two balloons to reach the same size. You obviously need valves fitted in the proper places and you could fit pressure gauges on either side as well, but something to this effect ought to work in terms of obtaining rough estimates. Disclaimer: I am not a physicist and wouldn't know any of the practicalities involved.

 

[Dr G]

In the most simplistic fashion, two identical balloons mounted on either side of the mouthpiece. You inflate one, open a valve and measure the time how long it takes for the two balloons to reach the same size. You obviously need valves fitted in the proper places and you could fit pressure gauges on either side as well, but something to this effect ought to work in terms of obtaining rough estimates. Disclaimer: I am not a physicist and wouldn't know any of the practicalities involved.

That's a good start, but the resistance includes the vibrating reed and its dynamic effects.

Disclaimer: I spent 30+ years as an experimentalist. Seeing the faults in an experimental design is the easy part - figuring out how to overcome them is tough.

 

[rhysonsax]

Resistance on the same mouthpiece and reed can vary for the same player depending on how much mouthpiece they take into their mouth.

Rhys

 

[turf3]

Connect a small diameter tube to a Dwyer manometer, slide it along the upper part of the mouthpiece, and measure the air pressure inside your mouth as you play.

 

[Pete Thomas]

Resistance on the same mouthpiece and reed can vary for the same player depending on how much mouthpiece they take into their mouth.

I wondered whether to say that or not initially.

I'm sure it may well be true but haven't noticed it myself to any significant degree.

But it would throw a huge spanner into the works re: any kind of measuring system or device.

 

[squeak]

I spent 30+ years as an experimentalist. Seeing the faults in an experimental design is the easy part - figuring out how to overcome them is tough.

Ditto. My suggestion was really just meant as way to get a rough estimate without some ultra-fancy machine.

Resistance on the same mouthpiece and reed can vary for the same player depending on how much mouthpiece they take into their mouth.

That is a great but also different point. It would be important to distinguish between setup and player and the latter would be inherently difficult to quantify. For instance, biting on the reed could make any mouthpiece feel resistant.

 

[Dr G]

I wondered whether to say that or not initially.

I'm sure it may well be true but haven't noticed it myself to any significant degree.

But it would throw a huge spanner into the works re: any kind of measuring system or device.

Do you expect "resistance" to vary with output volume? What about as a function of pitch for a particular horn?

 

[vries1]

Here’s a small study that discusses some of these aspects: https://repository.tudelft.nl/islan...0d7-92ba-6c7b34a2b053/datastream/OBJ/download

 

[Dr G]

Here’s a small study that discusses some of these aspects: https://repository.tudelft.nl/islan...0d7-92ba-6c7b34a2b053/datastream/OBJ/download

From the final paragraph of Section 3.: "The player experienced that the copy mouthpiece was the hardest to play. This can be explained by the fact that the overall level of the differences with respect to the original mouthpiece is higher and more extended for the copy mouthpiece compared to the other mouthpieces."

That indicates that the study is unable to control the quality of the copy, therefore any variation in data for other mouthpieces based on that copy is questionable. Too bad they didn't ensure that the facings were good.

As a colleague of mine once commented during the review of a very expensive study "This was an elegant experiment conducted with ****ty specimens."

 

[mizmar]

Here’s a small study that discusses some of these aspects: https://repository.tudelft.nl/islan...0d7-92ba-6c7b34a2b053/datastream/OBJ/download

I was about to suggest input pressure vs output volume /power; in analog with a torque distribution for an internal combustion engine. What they define as Effort. I'd have been interested in a pressure vs output power distribution for a fixed note... is there a power band? I suspect so (and not the heavy metal kind).
My, probably wrong, intuition is it's a bit like anyone who's ridden a motorbike will have experienced; you hit the power band and things just seem to flow easily

 

[Phil]

As G says, it would be absurdly complicated and have limited benefit unless you were familiar with a number of basline values. Just because you get a value (Im making up the number) of 3.33 vs another piece that is 3.55 does not mean that you would actually like the lesser one better...even if you like free blowing pieces.

As much as many people want to believe a lot about mouthpiece work (and I suspect a lot of horn design) is not an exacting science. Its trial, error, and the work of experience. Yes, you can do the math on a facing curve and chamber volume/dimension but that is where most the numbers stop.

This is why I believe in real play testing of mouthpieces as they are being made. I know of one business that claims to play test. For this company play testing consists of taking the mpc, holding the reed on BY HAND and blowing. I guess if it makes sound it has been play tested! Play testing needs to involve a sonic experience...I wont go any further into this but I can imagine you get my point and Im not wanting to derail the thread. It just all seems connected in my eyes.

Also, there is variance in mpc making that can dramatically influence the experience of resistance. In the end the numbers, IMHO, would be just another buch of numbers to argue about since your piece made by the ACME Company may have different resistance than mine.

 

[Pete Thomas]

Do you expect "resistance" to vary with output volume? What about as a function of pitch for a particular horn?

I'm not necessarily expecting anything, just an idle specualtion while not having anything better to do.

It's partly based on cusomers who by a 7* then return it for an 8*, because there is less resitance than expected.

I call it the "I'm a 7* man" syndrome.

 

[Pete Thomas]

Sorry folks, we had to do a database restore and lost a couple of messages, I think we lost yours @Jimmymack - sorry about that it wasa good post so if you remeber it please do repost.

 

[Phil]

A resistant server?

 

[squeak]

As much as many people want to believe a lot about mouthpiece work (and I suspect a lot of horn design) is not an exacting science. Its trial, error, and the work of experience. Yes, you can do the math on a facing curve and chamber volume/dimension but that is where most the numbers stop.

I believe you, but that won't be measurable. Not sure what Pete was requesting but some sort of device that can measure resistance of a mouthpiece to airstream seems conceivable. What the player senses is quite likely a different matter. That, I suspect, is answered only by play-testing and/or "idle speculation", although I wouldn't exclude the possibility that an AI idle speculator devise of some sort already exists. It probably does.

 

[Dr G]

And then there exists the mystery of why a piece plays with greater apparent ease for someone with good air support and a developed embouchure. For example, I played a Lamberson J8 for a great many years - large chamber, no baffle, 0.120” tip, and Alexander DC 3 reeds. I had no problem playing the full range of dynamics with ease, yet many others that tried it, couldn’t get a decent sound out of it. Why is that? It didn’t feel resistant to me.

 

[Jimmymack]

Ok, here’s a shot and I hope I don’t break the internet again. The point was that we all think of the tip we play as a guide to what we look for if we venture into the swamps where new mouthpieces live. If I go into a shop one of the first questions will be what tip opening do you play? So I’m an 8* man because that’s approximately the tip opening I usually play and will judge others against. There are a couple of problems with this, one being, as suggested, that the tip opening is only the beginning, an 8* with a long lay can easily play like a 7* and what that does to the sound is somebody else’s guess ‘cos I don’t know, another is that most of the places I go, on these rare occasions, rarely have a choice of tip openings so I can’t compare to see if it makes a difference and usually come home with nothing, or worse, I come home with something that is useless to me. Descriptions by the makers sometimes give this kind of data but it’s still all subjective in the end. The only way to have any idea is to blow the things, and they don’t have a decent range to choose from. A third problem is that after an hour or so of torturing myself I can’t make a sensible decision, and fourthly the try out rooms are usually terrible and don’t sound like anywhere else I might play.

Sorry this goes off the point a bit.