Luker here. I've been investigating these relatively unknown kits that are local (Australia) to me with top quality design, components and measurements:
https://www.wagneronline.com.au/hdsk-speaker-kits-complete/speaker-kits/audio-speakers-pa/pl/
Specifically this MTM is of interest, check the PDFs in the downloads tab further down the page for freq response chart:
https://www.wagneronline.com.au/5-m...audio-speakers-pa/hdsk250-bv-74877/993926/pd/
From what I have gathered the kits were designed by Russell Storey of
http://www.stonessoundstudio.com.au in the 2000's in collaboration with a retailer here called Wes (later merged into Wagner). The dome tweeter kits have had a round of updates at some point, more info on the V1 versions can be found here:
http://d-s-t.com.au. Of note the 810921 HDS Tweeter, now sold as Scanspeak D2608/913000, was created in collaboration with Peerless specifically for these kits, and seems to be very well liked in speakers by other manufacturers and the DIY community.
The Stones Sounds Studio Artisan speakers shown on his website seem to be upgrades to the kits, but are hand built and measured to match, with upgraded crossovers / components. They are much more expensive, starting at $6.5K AUD from an email i just received. However the kits seem like incredible value and from bits of info seem to measure very well, at least in his very bespoke setup:
http://www.stonessoundstudio.com.au.../Loudspeaker_System_&_Driver_Measurements.htm