I was super happy with the Sig IIs after some second guessing during break-in.
They weren't quite as resolved as the CS1.6 but my main complaint was a veiled
quality in the midrange. I was able to all but completely cure that by biwiring
with a nice pair of Cardas (no way to know how much of that was because I
removed the low quality jumper or because of the biwiring). The rest of my
system has improved considerably since then. Most notably, I now have an Ayre
AX-5 Twenty which is crazy good. Being an audiophile, my nervosa got me to
wondering how much of that veiled quality was still obscuring the Ayre’s
excellence. I have an early Sig II with the plastic midrange diaphragm. The
natural step would be the Treos. I’ve heard the standard Treos and really liked
them, but never the CT version. Well, I pretty well killed my upgrade budget with
the Ayre so I started thinking about more affordable upgrade options that I
thought would be promising.
After that overly long preamble . . . the Sig IIs do have more bass than the CS2.4SE. By ear, they have full output down into the mid-30s with useful output into the mid-20s. Quite amazing at that price point. The 2.4s might have *full* output just a scotch lower but the bass falls off a cliff below 30 Hz. That means they can’t reproduce the left most key or two on a piano. That said, I’ve only sampled one song (Tracy Chapman’s “3000 miles”, with organ tones) wherein that deficiency was notable. In terms of bass definition and resolution, however, the Thiels are substantially better. That is an easy trade-off given my sonic priorities. The other area where I *might* give the Sig IIs a slight edge is soundstaging. The Thiels image beyond the bounds of the speakers just like the Sig IIs but spatial depth might be just a bit shallower. I otherwise prefer the CS2.4s in every way.
In addition to the better bass definition, there is greater resolution into the midrange and treble. Microdynamics can be almost startling. I’m hearing subtle percussions that were previously unnoticed on familiar songs. Inflections of backing singers more apparent. Decay of chimes, symbols, and triangles is superb. The Thiels *are* more transparent than the Sig IIs (the reason for wanting an upgrade) altho’ this difference is not as big as I had imagined (the Sig IIs are a really good speaker, competing with other designs at multiple their price). I think the Thiels are a scotch more coherent than the Sig IIs and overall better balanced from bass to treble.
My sonic priorities are neutrality, resolution, and transparency.
The Thiels better the Sig IIs in each of these. In fact, I think these Thiels
(again, with the audiophile capacitors in the coax feed) get most of the
performance of the very best speakers I’ve heard regardless of price. Other
than the lack of bass below 30 Hz, the only shortcomings I hear are image
density not on par with the best I’ve heard (might simply be sub-optimal
speaker placement) and, maybe, a slight “glassy” quality in the midrange. Perhaps
this is what Shane Buettner meant in his review when he wrote “slightly on the
cool side of neutral”? I would need a direct comparison with a reference
speaker to confirm this. Regardless, I think I’m getting 90% of the SQ of, say,
Vivid Giya G3s. And I suspect I can get even better performance by upgrading
the crossovers. Highly recommended!