There seems to be some talks of what if you want to upgrade the CS2.4? Overall I still think its only real weakness is the lack of low bass. For clarity and detail and natural integration, it's probably still some of the best even for today. Some newer speakers now are using fancier tweeters such as be dome, ceramic which may offer better treble detail but I am not sure it's necessarily better. For speakers using higher order filter, they can afford to add like a 10in. driver such as the Wilson or Dynaudio and so on, but for the CS2.4 being first order time coherent, it's not that trivial and given the constraints I am not sure if it's even possible. So with larger bass driver such as 10in, you get a more fuller sounstage abeit with higher order type of sound. I guess it's all a compromise. You choose the CS2.4 for all its strengths, but have to accept its lack of low end grunt.
But can we add an active subwoofer with some type of room correction DSP? Probably - just like what Vadersteen did with their top of the line offerings that costing even above $50K, which is why I am a bit surprise why none of the Thiel speakers follow this strategy which would not only solve the low impedance issue but still retains the time coherent characteristics.
So the best upgrade for the CS2.4 would probably be some of the Vandersteen top of the line speakers (although a lot more expensive) with a built-in subwoofer.
