Hardness vs. Density

[Chris at Owens Custom Calls]

Wade, you beat me to it.  That is the answer for density/hardness when talking about sound.  I imagine it like throwing a baseball.  Throw it at a wall made of foam and the foam is going to give a little or absorb some of the force.  It will still bounce off, but not that far.  Now throw the ball at a brick wall and see what happens.  There is no give and the ball is going to bounce a lot further.  If the reed vibrates and never touches the toneboard, air will continue to flow smoothly.  If it actually slaps, there will be brief periods of air flow interruption.  The air, instead of flowing under the reed, would now flow OVER the reed.  At least, that's the way I see it. 

[Wade@WEBFoot]

...The air, instead of flowing under the toneboard, would now flow OVER the reed.  At least, that's the way I see it.

I think you meant "reed" above where I underlined tone board...  correct?

I think of it this way... which goes along with what I think your saying...
With the sound being created by the "valving" of the air, and going with the thought that the air can flow smoothly - though partially interrupted cyclically by the reed - since the main portion of the reed is not touching the tone board when in its downward cycle...  the point at which the reed contacts the toneboard the air can no longer pass through the tone channel....  (over the reed rather than under it as you say). 

So, where does that air go?  Where can it go?  And what happens when that air is on top of the reed, and has no place to escape? 

Sounds like a "lock up" to me....   No?

There is no way that mylar has enough strength (read as "spring") to be able to overcome the 1-3 psi of pressure from a person, and open up the tone channel to let air out once it has been pushed over, and shut off the tone channel.

I wonder if the camera used for that table saw stop safety thing that saves hot dogs and fingers would have a high enough frame rate to see the reed?  Last I recall, I think the frame rate needed to be above 100kHz - maybe even as high as 150-200k?  I cant remember for sure...  But I know it was fast enough a laser vibrometer wasnt able to keep up at the upper register.

Anyone have access to a hi speed video camera?   

One quick clarification... Some have known me a long long time... and I used to subscribe to the reed slaps the tone board theory (probably 7-8 years ago?).  I even posted about it, and used examples that made sense to me at the time...  But, I had a buddy ask me a few questions that I couldnt answer, and gave a few examples that made "another way of thinking" possible...  Since, there has been some effort put into answering that question, and thus far, the best I can say, is my buddy was right (as are/were some other people who I didnt know at the time - but do now).  Though the info I have run across over the years doesnt positively verify it, it all seems to be leading that direction. 

So, for the record... yes I used to subscribe to the slapping theory, and no, I no longer do. Youre not crazy, I did change my stance.   

Just like eggs, chocolate, and wine being good for you... wait...  no thats bad for you...  no... wait, they changed their minds... they are good for you again...  There is an answer... but maybe they just dont have the right technology or information to answer the question yet.  So, for now, I like eggs and chocolate. :D

Cheers all!
Wade

[Chris at Owens Custom Calls]

...The air, instead of flowing under the toneboard, would now flow OVER the reed.  At least, that's the way I see it.

I think you meant "reed" above where I underlined tone board...  correct?

I think of it this way... which goes along with what I think your saying...
With the sound being created by the "valving" of the air, and going with the thought that the air can flow smoothly - though partially interrupted cyclically by the reed - since the main portion of the reed is not touching the tone board when in its downward cycle...  the point at which the reed contacts the toneboard the air can no longer pass through the tone channel....  (over the reed rather than under it as you say). 

So, where does that air go?  Where can it go?  And what happens when that air is on top of the reed, and has no place to escape? 

Sounds like a "lock up" to me....   No?

There is no way that mylar has enough strength (read as "spring") to be able to overcome the 1-3 psi of pressure from a person, and open up the tone channel to let air out once it has been pushed over, and shut off the tone channel.

I wonder if the camera used for that table saw stop safety thing that saves hot dogs and fingers would have a high enough frame rate to see the reed?  Last I recall, I think the frame rate needed to be above 100kHz - maybe even as high as 150-200k?  I cant remember for sure...  But I know it was fast enough a laser vibrometer wasnt able to keep up at the upper register.

Thanks Wade.  I edited my response, but you are saying exactly what I'm thinking.  If air flow is continuous, once the reed lays on the tone board, the air will begin to pass over the top essentially locking the reed down.

[dogcatcher]

How many of you as a kid made a whistle out of blade of grass.  Wider and thicker pieces of grass made different sounds than thin and narrow ones.  No toneboard to slap, just the wind vibrating the piece of grass.

Marvin

[clintfaas]

Great info so far! I appreciate the help.  A couple more questions that came from reading the responses.   

Lets say two woods are almost identical on hardness and density.  Will they still produce different sounds because of other qualities?

Secondly, (making numbers up here) could you expect similar results from a wood with a hardness of 3000 and a density of 50 and a wood that's 1500 amd 75?  Basically thinking high on ine aspect but low on the other?

[Wade@WEBFoot]

Marvin,
Another great analogy!  Forgot about that one!!
Too tight and it wouldnt buzz, too loose and it would flop over to one side and do nothing... but just right and boom... there ya have it.  And when it worked, it never tickled you hands.

Clint
I would imagine grain stucture will also come into play because it would affect the surface properties (open grain etc)

In terms of hardness/density correlations, there are some... but in regards to a duck call, its hard to say what that might be since everything would be based on the ear of the beholder :D

Wade

[Chris @ STW Outdoors]

Wow, talk about opening a can of worms. Sorry to hijack the thread. So, I had a discussion with Wade about this, roughly two years ago or so. It lead me to make a clear acrylic barrel and thread it for an air hose fitting so that I could observe the reed and air moved across it. The following picture is hand drawn and a little rough, but it depicts what I saw with my eye. Now, I know what some may say, "you can't see that with your eye". I would agree to a certain point. I can see the blurriness of where the reed is vibrating as opposed to the clear view directly between the reed and the tone board. Essentially I noticed that the reed will lock down on the flat portion of the tone board and vibrate just above the curved portion of the tone board. I almost got access to a high speed camera at that point to video the test, but never got all the way there. Anywho, I guess I do not have definitive proof other than what I observed and what I believe is going on based on what I saw. Now it would seem to me that this little experiment really stresses the importance of a smooth and flat surface for the straight area of the tone board. Perhaps a not so smooth and flat surface could account for raspiness. If it isn't holding the reed down very well then you could cause micro variations in the sound that is produced. Of course that is just me theorizing and trying to be an egg head which I am not, well kinda.

Oh and I like chocolate and eggs too.

[stumpjumper]

A reed will change hinge points with the application of different air (hence different ducks one can get out of a call) but from the hinge point forward the reed oscillates and does not touch the tone board. 

STUMP

[Tobin at Copeland Duck Calls]

A reed will change hinge points with the application of different air (hence different ducks one can get out of a call) but from the hinge point forward the reed oscillates and does not touch the tone board. 

STUMP

Bam...you just hit the nail on the head. 

T

[clintfaas]

No worries on the different discussion.  Ive read several things on this topic and was also under the impression that it hit the toneboard.  What is drawn there makes perfect sense though.  Regardless of HOW the sound is produced, that drawing helps me understand tone boards a lot better.  specifically how changing shape may affect how sounds are produced.

[Chris @ STW Outdoors]

I am glad it helps. I drew that with no real scale at all. However, If someone copies that tone board dimension and it makes the best call ever made, then I reserve all rights to the design

[Joe aka COLD @ J. A. Kolter Calls]

Great info so far! I appreciate the help.  A couple more questions that came from reading the responses.   

Lets say two woods are almost identical on hardness and density.  Will they still produce different sounds because of other qualities?

Secondly, (making numbers up here) could you expect similar results from a wood with a hardness of 3000 and a density of 50 and a wood that's 1500 amd 75?  Basically thinking high on ine aspect but low on the other?

The answer to your first question regarding 2 woods identical in hardness and density producing different sounds is yes of course they will be different.  There are way too many other characteristics that differ from each wood specie.  Things like tonal quality, silicate or oily content.  Every tree specie can vary greatly on where it grew and how long it took to mature in size, etc.  In other words, no two trees of the same specie are exactly
alike.

[Joe Short]

Count me among those not convinced. Hate to but I cannot accept that my toneboard, an upslope design, does not exhibit "reed slap." Patiently awaiting being proven wrong. "I've been wrong before... ONCE."
Nothing wrong with being wrong, hard to learn from your mistakes if you never make any. Flame on.

[Gouldman]

This horse has been beat to death on a many of forum.... I'd say Wade, Stump, Doc Hull and a few others make a pretty good case for the larger part of the sound coming from reed oscillation.
Ole Turner might disagree? I too would love to see some video? 

[Wade@WEBFoot]

We oughta chase down someone/some place with a high speed camera....  dunno what it would cost... but Id be in for some money just to be able to see the reed in action. 
 

This stuff is right up my alley... this is the kind of stuff that gets me wound up...  But Im sort of an odd duck... (pun intended)  I dont get so much into the different colors and finishes and this and that and so forth.....  but understanding that sound...  that sweet music... thats where its at for me.  :D

The one advantage of occasionally digging out the horse and beating it again, is the new people... who knows... maybe one of the new guys has the video studio for the table saw hot dog/finger saver thing and has a super high frame rate camera.
Never know.

But probably in fairness to Clint, we prolly shoulda started a separate thread :D  Sorry bout that Clint.

Cheers
Wade