Vandersteen

I owned the 3a sig's (just sold them today, so I can get the Treo's), and I never noticed them 'falling apart' on certain music.
As others have mentioned, what components are you using with the Vandy's?
Johnny Rutan, audioconnection, is a font of Vandy knowledge and would be a good person to contact with your problem.
Bob

Not a 3A Sig but I do have the 2CE Sig II powered by McIntosh monoblocks MC 601, 600 watts per amp and never experience any falling apart. I love my 2CE Sig II as they just get better and better as it aged.

A question for all the people who say their Vandys don't fall apart on large scale music -- at what volume level are you listening?

The point of the OP is valid imo. There are many speakers which are superior to the Vandy II and III in terms of tightness and accuracy of the bass especially. I found this to be the case regardless of listening level. These models of the Vandersteens are not the last word on definition and cleanness, and bias in favor of the speakers does not change that. I owned the II CE and got tired of the indistinctness of the low end, so I moved to as far afield as I could, the Maggie 1.6QR. Of course that model has its own issues. Both of these speakers are bargains but have distinct shortcomings. 

In terms of their performance to price the lower end Vandersteens are highly recommendable, but certainly not in terms of absolute performance. This should not be shocking, as after all Vandersteen has improved their lines markedly with much superior and much more costly models like the 5 and 7. 

I had Vandersteen ll CE Sigs for a couple of years and kept switching amps, both tubed and solid state, including Krell, Rogue Audio, Musical Fidelity and Conrad Johnson in the hopes of "waking them up." Ultimately, I could not get them to achieve the level of dynamic range I wanted. I finally found my desired level of punch in Thiel 2.4s and have enjoyed them for several years now with no inkling of swapping them for another speaker.