They were intended as a rival to the KEF105. They used KEF B139 and an Audax mid and tweeter. Falcon had no input except manufacturing the RAM designed crossover. I remember we loaned RAM a pair of KEF105's to reverse engineer their own version - hence the 400. We had an open evening where customers could hear both the 105 and 400 together switching between the two very interesting comparison. Never felt the bass on the 400 to be successful - the 105 was far superior. The midrange was certainly more pronounced on the 400 without being fatigue inducing. Never did like the top end of thise Audax tweeters although many people did - again more open but not fatigue inducing. Although the 400 sounded more impressive than the 105 on A/B comparisons I couldn't help concluding that the 105 was a better listen overall in the long term. Nevertheless, the 400 was an excellent attempt at a 105 rip off.