I have build a crossover for my panel. The highs are way better now. Relatively smooth up to 10 kHz, than falling rapidly.
I see this 10 kHz falloff on all my XPS 2cm panels. Seems to be material specific. The bended panel I am working on uses XPS with 5mm thickness. First tests by just holding an exciter against it suggest that they may play up to 20 kHz without falloff.
Like I've always assumed that a single exciter per panel is the best way to go for the most accurate of sound.....with that said my next project is to make a 2 way with two separate panels utilizing 1 exciter per panel instead of 2 exciters on one panel....
I second this. The panel I built sounds horrible when increasing the volume. The tweeter produces strong resonance distortions at ~470 Hz. Seems like the shaking of the panel is to much for it. I think I try to add a stick of wood diagonal at the corner to separate the tweeter part. Inspired by the bertagni speakers.
I wish there was a way to let you all hear them I bet yawl be blown away and even more so when you realize it cost almost nothing to build them. LOL
That is the negative part of this hobby. You can capture an image of your speaker and show it to the world but you cannot let the world hear it. The only chance is to document your journey to encourage people to try it themselves.