Advise for new speakers for my basement exercise room


new member. I would  appreciate your expert advise for new speakers for my basement exercise room 15x25. Hard floor and walls with  4 windows and 9' ceiling. I am using near mint JBL 112s but hi frequency sounds are not realistic. Lows are great.  System is Nak CA7 pre, PA7 Nelson Pass 200w amp, and Sony ES707ESD CD player, AQ and Morrow cables.  Like upbeat music for exercise. Don't have time and do not want to go and audition and comfort level is about 5k or less.  My Mission 770s sound better than the JBLs there, but are needed elsewhere.
Thank you everyone for your advise and time.
johnmabaltimore
I mean, this is not a use-case for high-fidelity critical listening. As others have said, acoustics/room treatment are going to be sub-optimal at best, the listener is going to be moving around the room so listening axis is variable both horizontal and vertical, air conditioning may need to be on..

Good SPLs, dispersion, and ease of use/convenience are needed.

I say just get some bigass active monitors  (e.g Genelec 8350s, ATC SCM25/45As) that you like the sound of and move your nice hi-fi equipment to another room like a home office.
Most of the professional work out spaces I have seen use the JBL pro monitors, 4312s or similar.  I would think the L112s should work , but it is all subjective.
You said "..my Mission 770's sound better" I think you have yourself an answer unless you really want something different. Get another set of Mission 770's for the workout room (or rethink what you are doing, use the Mission's you have in the gym, and splurge on a set of something new for 'elsewhere')