Sweet spot or not on pot call

[MG150]

I saw somewhere some people discussing whether a pot call has a sweet spot or not.My anodized aluminum call builder said you could play his call all the way around the call.Most glass calls come pre-conditioned from the builder.Lonnie Sneed told me he conditions the whole surface of his Green glass call and can play around the whole call.I didn't ask him about his Hot Hen Slate.One other thing that was being discussed was if possible play the call against the grain of the pot.My Crystal call came pre-conditioned from the builder and you play it against the grain of the pot.I was wondering what thoughts  call builders and hunters have on these ideas.

[chuckward]

On slate surfaces I've never noticed a sweet spot. Chuck

[Skeeterbait]

Slate, aluminum and ceramic surfaces can be played all the way around but seem to all be sweeter a certain distance from the rim and not in the center.  I think this has to do with the frequency of the vibrations changing as you move away fron the rim.  All other surfaces that you condition you orient the call based on the direction of your conditioning.  Some play 90 degrees to the conditioning, I like palying 45 degrees to the conditioning.  But even these seem to be sweeter a certain distance from the rim.  I have not observed the orientation of the grain of the pot itself having a noticeable effect.