Studio monitor suggestions under $6k used

[fuzzdose]

Maybe you should ask at GS with more details or even examples what is going wrong with single pair of O310s.
Your question sounds like you need something "different" to overcome inevitable bias of single monitoring pair. But it's not easy to guess what is "translate not quite right" without examples.
I'm not sure if you will find something much better than O310 under 6K. Maybe used ATC 25A pair like
https://reverb.com/item/4550938-atc-loudspeakers-scm25a-pro-studio-monitor-pair-mint-condition
They have good reviews from pros like
http://atcloudspeakers.co.uk/2019/0...-for-atc-scm25a-three-way-reference-monitors/
.

I've looked at and heard the atc scm25a for a while now. Never had them in my own room though. The mid resolution is impressive. I'd love to see some detailed tests on these. There was a report in resolution mag years ago that showed some time coherance issues. Apparently ATC disputes the findings but I have yet to see them publish data that clears the issue up. Anecdotally, most people love them but maybe dropping that much on monitors makes you look past its faults, ha. Anyone have experience with the scm25a?