I mean like a giant wine glass that has a circular opening that can be covered by a round and disc shaped portable speaker?
Something something resonance?
What is the effect when you direct sound into closed dead-ends/sealed containers? Especially when sort of elevated and not connected to the ground or other surface…
You should try it out. Depending on the decibels that speaker can push it might just blare through it but at lower volumes with a sensitive mic it might be interesting.