I’ve been reading numerous threads on this forum in an attempt to isolate what would generally be regarded as the “best” pair of speakers in the 5K range. I understand that “best” in this context can be both subjective and objective.
As you know there is no "best" of anything. In the case of speakers, it is strictly subjective. I can list ten current models at your budget and it would be difficult to arrive at a consensus. I would probably get replies adding even more. There is no objectivity in this.
The best speaker is only the one that sounds best to you!
I can tell you I’ve listened to quite a few speakers in my day, including the relatively new to market Golden Ear Triton One’s, and I still feel the 412s hold their own (if not sound even better).
You may be answering your own question. To your ears, you already prefer what you have vs. a new offering at your budget. I suggest you go out and listen to several others, using music that you know very well, and that can be driven by an amp of comparable quality and power output to what you already have.
Specs do have their uses, but they can't tell you anything about sound quality.
Zd is absolutely right. Specs are good to tell your amp will match up well with the speakers you intend on auditioning but will tell you nothing about how they actually sound. And in your case you have a very good amp and I am pretty sure that it will properly drive just about any speaker you will encounter in your auditions.
This is just another reason why to go out and hear as many speakers possible so you can find the speaker that is best for you. Or find out that you may already have it.
