After 6 months of trial and error (and a lot of calls in the trash can), I have my copper, glass/crystal and slate calls sounding great with consistent rollover and rasp. I made my first aluminum call this past weekend. Shedua pot with blasted anodized aluminum over glass. The call sounds flat, with absolutely no rollover and almost no rasp. I need some advice on how an aluminum call is constructed differently than glass and slate calls. More gap between soundboard to and surface bottom? Larger or smaller pedestal? Solid pedestal? Segmented pedestal? Other? Please help save me from frustration!! Many thanks for any advice or tips.