YBA speakers are an odd product, as far as I know they are designed by YBA himself, who also selects and supplies the trasductors and the main components of the crossover filters. The whole speaker is actually manufactured by SILCO, the italian distributor of YBA. SILCO is a family run operation that might make a few hundred pairs a year, if that many. I was there and can tell you that it is not more than the workshop of a very gifted but very confused artisan, no industrial structure at all. It took me almost 2 years to receive my sonatas because they guy did not like the new woofers he was getting from France and kept sending them back.
GALA's are very good speakers, especially when paired with 2 of their subwoofers, CONCERTO's are .... well everybody makes mistakes at some point in their life! SONATA's and MINIMUM in their various version (regular MFD cabinet or solid wood cabinet) are YBA answer to the english minimonitors which are always so popular in Europe. Personally I have a pair of SONATA in their latest version (new double coil woofer) and I find them outstanding, I compaired then with LS 3/5 and ProAc Tablettes and still find them the better speakers. To drive them I have YBA CD2, YBA 2DELTA Pre-amp and YBA 3 main amp.
If you want more technical detail on these spaekers you can find it at www.silco.it, it is not the best organized website but has some interesting stuff.
