Looking for new speakers

I'm looking to upgrade my Thiel CS3.6s -- I never thought I'd say this, but I think they are not good enough for the rest of my system. 

Within the last two years, I've upgraded my amplification to a Luxman L-509x integrated amp, and upgraded my turntable to a Luxman 171a. Overall my system sounds pretty good --- MUCH better than before the upgrade. However, there are some recordings on which there is definite distortion, particularly especially well-mastered 45s. For example, Diana Krall's Look of Love has so much distortion it's almost unlistenable. Even in the 33s, I can now hear a low-level distortion.

My theory is that when the Thiels were manufactured, the electronics were not quite as good as they are now, and definitely the recordings were not mastered as expertly, so these weaknesses did not show up. They were great speakers in their day, but, alas, I think maybe that day has passed, at least in my system.

I'm looking for something in the $10K - $15K range. Not sure if there's anything in that range that would be enough of an improvement, but I'd love some suggestions. It's been many years since I've looked at speakers, so I'm not really up on what's available at that price point.
I have a room the same size as yours and listen nearfield mostly to vocals and small ensembles. The best speakers I ever heard in this space have been Reference 3A De Capos. They are standmounts, quite sensitive. Strongly recommend you look into them. 
I agree with a couple of people here, ignore the 1st responder unless you want to go backwards in sound quality.
I also agree with others to try a different source. Also, try different speaker cables, even some cheap 16/14 gauge wire just to see if the distortion goes away.
Do you have any friends that you can borrow a pair of speakers or do you have another set of speakers that you can hook up to see if the distortion is still there? In the end, if it is the speakers, there are many different speakers in that range of expense that would be better than what you have IMO:
Totem Winds, Usher TD10 or TD20, Revel Studio 2
I haven’t heard anything better than the Vandy Quattro CT at that price point.  But speakers are like ice cream; so many flavors, we all have our favorites. Good luck and report back on what you choose.  
If it turns out not to be a problem elsewhere in your system or with the files themselves, and you are still interested in replacing your speakers, keep in mind resale value is important unless you are not an upgrader. That was a big reason why I bought B&Ws, and why I bought my BMW.

Also, I would be cautious when evaluating recommendations offered here for specific speakers. No one knows enough about your tastes or your room or how best to inject synergy into your system. I learned the hard way to keep my own counsel.

Last but not least, try to avoid the flavor of the month, most likely it will cloy sooner rather than later.