The TC-50s are better and more balanced than the TC-60s. The 50s sound smoother, have superior imaging and soundstaging, with just the right amount of speed, detail and air. Also, the sealed enclosure makes integration with a sub better. I've been through over a dozen speakers in the last decade, but I still have the 50s.
The 60s, while a decent speaker, sound more like mid-fi. I think Mr. Bau lost the "Spica" magic when he tried to get too much bass out of them. However, he may have succeeded in creating a speaker with wider mainstream appeal- closer to boom sizzle than high end. (And they do not come close to going down into the low 30Hz range, as mentioned in one of the above posts.)
The 60s, while a decent speaker, sound more like mid-fi. I think Mr. Bau lost the "Spica" magic when he tried to get too much bass out of them. However, he may have succeeded in creating a speaker with wider mainstream appeal- closer to boom sizzle than high end. (And they do not come close to going down into the low 30Hz range, as mentioned in one of the above posts.)