Andy, I'm thinking out loud here, so forgive me if I'm talking from my behind, could a shell in a shell work? Say a 22" x 16" shell with another shell of 21" x 17" inserted into the 22", with a system which secure the smaller shell inside the bigger one, the fact that the smaller shell is 1" deeper than the bigger one, 22" heads could fitted on batter and reso with a 22" hoop but touching simultaneously all bearing edges (22" & 21" or 20", 18" for that matter). The smaller shell would give most of sound, no?
It can also reverted back to a 22" in minutes by removing the smaller shell.
What do you think, possible? or I am totally dreaming
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