Losing air at bass drone

[el gaitero]

Originally Posted by Keith H

Well, I have managed to zero in on the reed and now am getting an avg of 1.20 following Bruce's test. So I'm happy now. Ended up opening the tongue the whole way and slowly bringing it back. Thanks

Do you know what n20 chanter reed strength?

[Keith H]

Originally Posted by DapperDan

Is the tongue on the bass reed airtight? I mean if you mouth-blow the reed until it shuts, does air still get through? I had this issue recently and retired a set of reeds because of it.
From what I understand this used to be a standard test for cane reeds, and I would think applies to synthetics, though I don't hear about it much.

Edit: I believe Bruce Hitchings addresses this in the linked video, I watched it recently, so sorry to be redundant

Hi Dan, I narrowed in on the bass reed and ended up opening it all the way and slowly little by little closing it up. Hit pay dirt so I'm getting avg 1.20 when checking the whole bag. Being redundant isn't a bad thing it mean you, Wil and Jim had the right path. Thanks

[Keith H]

Thanks everyone for the good tips Got it and the bass reed was the problem (not counting me).

As explained I ended up opening the tongue then slowly closing it up until it sealed properly. Also clean it.


Well it's all part of the fun, right


Cheers and thanks

[el gaitero]

Originally Posted by will103

Hi Keith, I had the same problem. I found this useful:

https://www.youtube.com/watch?v=Mc4ACA1WYcg

Ta will

I’ve met Bruce ..great chap. I’ve always meant to give him a bell to ask why ..at 2:55. ..he states the reeds ( tongues) are closed more than they are open.

To me its one or the other...in equal amounts ..on /off,..open/ closed ..it can’t be more of one than the other.

Did I mishear it?

This method is a great set up tool for anybody. I have anybody I work with on pipes do this regularly for their own epiphany moment.

[CalumII]

Originally Posted by el gaitero

why ..at 2:55. ..he states the reeds ( tongues) are closed more than they are open.

No, he's correct. The reed is open. Air rushes through: the Bernoulli effect means the pressure above the reed is higher than underneath, so the tongue is pressed onto the reed body and held there by air pressure.


A wave front from the tongue clapping shut now moves up the drone. At the far end, it reflects from the open end and travels back down, moving at the speed of sound. When it reaches the reed, it flips the tongue open again. Air immediately starts moving through, creating a Bernoulli effect, and....notice how the tongue was clamped down on the reed for most of that.



(this isn't perfectly accurate from a physics perspective, but it's a pretty good model for thinking about what's going on and predicting how things affect the sound)

[el gaitero]

... when the drone is in tune,..on an ocilliscope the amplitude and wavelength show up as being mirror image equal above and below the x axis.

[Keith H]

Originally Posted by el gaitero

Do you know what n20 chanter reed strength?

Sorry got me on that n20? Chanter reed is easy but actual strength I don't have the means to measure that.

[el gaitero]

Originally Posted by Keith H

Sorry got me on that n20? Chanter reed is easy but actual strength I don't have the means to measure that.

Jori Chisholm sells a manometer set up for pipes..used to check how steady air pressure one is playing ( = steady tone)..also convenient to confirm strength of preferred chanter reeds ...especially when ordering.

[Keith H]

Originally Posted by el gaitero

Jori Chisholm sells a manometer set up for pipes..used to check how steady air pressure one is playing ( = steady tone)..also convenient to confirm strength of preferred chanter reeds ...especially when ordering.

Assumed that might be what you were referring to. Worth looking into. Appreciate the tip.

[CalumII]

Originally Posted by el gaitero

... when the drone is in tune,..on an ocilliscope the amplitude and wavelength show up as being mirror image equal above and below the x axis.

Yes. But that doesn't tell you anything about the reed tongue cycle.