Hello Colin,
I have read this post with great interest and congratulate you on creating such a great set of speakers, which look the 'bis' too.
Looking through your photos I was however more than intrigued with a particular image I spotted (which was incidental to the focus of the photo): And hope you can tell me more.
Your ninth photo is a view of the whole assembly but what caught my eye was the black & white photo montage picture on the wall above your rack.
It shows various instruments, central to which is the badge that can be seen as "Laurinat & Co Berlin"........ is this a picture you created yourself or is it one from a commercial source ?
The significance for me is that as I type this I am sitting next to Mrs. vt's piano, which was made by Laurinat & Co, Berlin !!
The World is made up of such amazing coincidences and I can't believe having spotted this in a post about DIY OB speakers