Pot call question

[Idawg]

Hey everyone I am new to turkey hunting and seeing how I am a little obsessive with things I am certain I have found my new addiction.  That being said I was looking how pot calls are made and all the different wood and materials and I had a question for people who are more experienced than I am.  I am in the optical business so my mind probably doesn't work like a normal persons.  Has anyone ever tried a concave or convex playing surface or soundboard? Also there are materials that I have at my disposal for use that are glass, Polycarbonte, Cr-39, and trivex that we make optical lenses out of just wondering if any of these would be suitable for a pot call or if they have even been tried. I know I'm probably not the only one who has thought of this but I wasn't sure if a curved surface would change the sound of a call or not just a couple of questions any info would be great. 
Thanks,
Ben

[mmclain]

You may get that to work .   you'd probably need to curve the sound board too

[TRKYHTR]

I think Somebody came out with a concave soundboard last year. Still had a straight surface.

[Idawg]

I was just wondering if sound was similar to light in how it traveled.  I am not as familiar with the mechanics of sound but light will converse or spread out based on the curvature of the lens or surface just wondering if anyone else might know more about sound than I do.  Thanks for your responses though. 
Ben

[mastevt]

Be curious  to find out how it sounds.  One thing to remember, distance from the top of soundboard to bottom of the surface (air gap) is pretty critical.  Using a concave soundboard will throw that consistent air gap off.  Depending on how you glue it in, concave up or down, you will more than likely create a dead zone or flat spot because of it.  I'd definately be willing to try it.  Got nothing to loose except for a little wood and time. 

[Idawg]

 Well I know this is a technical issue that might not change anything but what i was looking at doing would be matching my convex and concave surfaces so that the air gap is consistent.  I just wonder if the sound would travel differently from a curved air gap as apposed to flat one that I currently have on a call.  Also what would you want the thickness of your sound board and playing surface just having some different ideas that I might try. 

[mastevt]

Glass soundboards are right at .085.  Acrylic ones I have are .125.  I make my wood ones at around .100.
I would think if your material fits in this range, you should be find.  Another thing to concider.  Are you going to shape the back wall to conform with the arch of the soundboard?  Reason I ask is this measurement also effects the call, although its not as critical IMHO. 

[Idawg]

In your measurements I'm assuming that you are using inches.  I normally work in millimeters so there is a conversion there. But is most of my mesurments are correct. then a 3" pot call would need a 2.75" or 70mm soundboard with a 3" or 77mm playing surface.  I will have to look at the thickness I'm not sure how that would convert but that sounds kinda thick. Normal optical lenses are required to have a minimum thickness of 2.3mm at the thinnest point.  I would imagine that a 1 to 1.5 mm thick playing surface and soundboard would be optimal as far as not damping the vibrations.  Let me know if I'm on the wrong path.  I haven't thought about changing the pot at all until that was brought to my attention.  Might try one with curved back wall and one without just got to get the pots now.  thanks
Ben

[drenalinld]

Be curious  to find out how it sounds.  One thing to remember, distance from the top of soundboard to bottom of the surface (air gap) is pretty critical.  Using a concave soundboard will throw that consistent air gap off.  Depending on how you glue it in, concave up or down, you will more than likely create a dead zone or flat spot because of it.  I'd definately be willing to try it.  Got nothing to loose except for a little wood and time.

I am not challenging this as I have never built a pot call, I just find this critical distance to sound board puzzling since some really really good pot calls don't have a sound board at all. I have read many good call makers state this, so I am sure that it is correct. It does puzzle me though.