Bill,
Thanks! You know, you really do need both.
rnhood,
The anechoic response is +/- 2dB 26Hz - 24kHz. -3dB @ 25Hz & 30kHz.
In actuality, the above +/- is our published "spec." I don't let anything out the door if it's not less than +/-1.25 dB. That's mainly because the systems H.F. response is dominated by the waveguide. It eliminates most of the diffraction effects that cause high "Q" peaks and dips in the frequency response of most speakers. Once you eliminate them it becomes relatively easy to get a +/- 1dB response. If I have an enclosure that's worse than that, I immediately know something is wrong. So...I don't let them out the door unless they're that flat. If they work - they are. If they're "broken" - then they're not. It definately makes for easier QA control.
As far as a "concrete" enclosure goes? Y-e-a-h baby. Who wouldn't want one? But...there's always the "devil" ($$$) to pay. You don't even want to know what that would cost to ship - let alone build! While it's certainly not concrete, our 1.5 inch thick, constrained-layer damped walls and heavy internal bracing go a long way in emulating that level of performance. They also make our stuff affordable without a mortgage.
-Bob
