Went to Colin's last Saturday to play around with some speakers. Among other things, I took some measurements of the current iteration of these prototypes.
There's a bullet-style tweeter (Ciare? - Colin will know) running with a cap and an L-pad. We did some adjustments to the L-pad:
And also took some off-axis response curves:
The tweeter seems to do well at keeping the sound consistent in its coverage angle, but drops off quickly outside of that. The ~7kHz peak is courtesy of the Lowther.
Measurement distance was roughly 1m, so there's definitely some "room" coming in.
I think they're about as good as they'll get with this driver complement. I'd still like to try the Supravox with a good 1" compression driver, but that's getting away from the design brief.
Chris
PS - It's just occurred to me that the HF level being set by ear might be in response to the fairly narrow (and forward-only) directivity of the tweeter. The relatively (compared to at the listening position) close mic placement would mean mostly direct sound, whereas further back you hear more off the off-axis+reflections, which will have less HF content. Putting the mic at the listening position would've confirmed that - something to try next time.