IsoAcoustic had to design threads specially for the MLs that feature the base-mounted tray that houses the bass amp. The threads need to be very long to reach the 8mm spike threads that start some distance in because of the hex section for amp removal. When I bought my 13As and wanted to fit Gaias, I had to get suitable threads made at my local marine hardware engineering equipment supplier, but when I advised IsoAcoustic of the spec required they decided to add this special to their range of optional threads - great service from a helpful brand.
My own view on speaker TYPES is that the room should be the major consideration when choosing between conventional box, electrostatics, horns, omnis, etc. Your preference in music is also important of course, but unless the type of speakers matches your room’s features, you'll always be lacking something.
I too considered that the 13A was probably the best value model in their range when taking price and performance into consideration and they were the size that I'd still go for if my room suited els speakers - but sadly it doesn't, so I’m sticking with less room-fussy horns!
