Maple closed reed with acrylic insert

[ninthinning]

Picked up some fine turning stock from rainshadow.  This was one of the pieces he threw in with the order to fill up the box.  Most of the stock I bought from him is highly figured.  This call is a two piece enclosed reed with a turned acrylic insert.  Step drilling creates crisp loud sound with very low air.

[iahntr]

Looks good. I got some from him a while back, but haven't had a chance turn any yet. Lookin forward to it.

[THO Game Calls]

Step drilling creates crisp loud sound with very low air

I would suggest that the crisp sound is actually a function of the acrylic insert acting as the barrel of the call.

The volume is also a function of the material, and the low volume of air needed to blow the call is a function fo the inside diameter of your insert at the widest end.

Step drilling does have some effect on sound, but in your case, the acrylic does most of the work.

You could eliminate the maple shell and and save the wood and have the same sound from the call.  Just not as pretty.

Just my opinion, based on having worked with several thousand acrylic and wood calls over the last 5 or so years.

Al

[ninthinning]

I buy that Al,  The wood is just dressing for the acrylic call.  Plan to set up an experiment using identical calls but one smooth and one step drilled.
Thank you,
9th

[THO Game Calls]

Actually, the wood body of the call may mellow out the harsh sound of the acrylic by damping the resonance of the acrylic.  It is not a bad idea at all.  Sort of a compromise between an all acrylic body and an all wood body. 

To test a step drilled call and a smooth bore call is beyond the capabilities of most of us.  You have to control the amount of air through the call, and it would be too easy to subconsciously skew the results the way you think they should be. 

The big reason you see so many acrylic duck call inserts step drilled, in my opinion, is that people either a) don't know how to sand the steps out, or b, don't want to take the time to do it.

I am aware of the theory behind the step drilling, as compared to cone speakers, and I don't buy it.  I think volume is a function of

1) how much air gets to the reed
2) how much back pressure is in the barrel (which is determined by the diameter of the bore and the length
3) the material the barrel is made of
4) and the final smoothness of the barrel.

Look at it like this - you don't see too many musical instruments with step drilled horns.

Al

[ninthinning]

Started an experiment today.  Made an air flow system that plays closed reed inserts.  Made four different configurations so far.

[keekee]

Thats cool 9th, tell us a little about it!

Brent

[Hawks Feather]

Looks like a good way to test things out.

Jerry

[ninthinning]

I realized that I don't really know anything about the shape of the closed reed exhaust and how the shape affects volume and other sound qualities.  Made a variable air flow device that delivers a constant air flow and pressure.  I plan to turn a series of closed reed inserts with various configurations and record some values and sound properties and quality.  The tester will also be refined.  Here I wanted to see if it was worth the effort so it was slapped together quick.  Learned something with this little test.
9th

[awh]

WTG Eric. Have you or are you going to test longer verses shorter inserts as well? I'd be interested in how much of a difference that makes too.

[ninthinning]

awh,  That's a good idea.  After I conduct tests on the batch of Closed JC reed inserts I have now I will cut them down a half inch or so.  Learning a lot but don't know what it all means. 9th

[Braz]

Wow, that is great. I'm really looking forward to seeing what kind of results you come up with. Way to go.   

[ninthinning]

Here is the first run.  All the reeds are from the same batch of LV 025 by JC.

The acrylic inserts all have different sounds but all but 2 and 3 sound good.  Units are dB. dB meter 8 feet from call.

awh, I cut no 6 to the same size as no 8, I'll let you know the results.

[caller223]

Jack Cain and Mossinger did this in 1959?? in desiging Circe calls !! Never saw the setup though.  i think Al mentioned the venturi effect on inlet side of reed-  all jet engines are designed this way.  If I remember phisics it was bernouli effect, big in front narrowing to middle and opened up to exhaust.
Richard           ps conrats on air rigging and enquiring mind

[ninthinning]

The main observation I take away from the limited tests I have run so far is the long cone shape makes a good sound and amplifies well.

[THO Game Calls]

The main observation I take away from the limited tests I have run so far is the long cone shape makes a good sound and amplifies well.

I refer you to my previous statement at the beginning of this thread.


you don't see too many musical instruments with step drilled horns

But no matter what you learn from this, you must come away with the following fact - and hold this fact as a constant, for it is almost always true for the average caller.

If the average caller wants his call to be louder, he is going to blow harder. 

We must therefor tune our calls so that they will accomodate the average caller.  Failure to do so will result in the dreaded "nice calls but they lock up when you really get on them", handle. 

It doesn't matter how good the call sounds in the shop, or how good you can get it to play.  What matters is how good it sounds to, and how well the average caller, can call with it.



Al