Anybody out there have any experience with something like this?
I plugged my bass into my modest little stereo back in the lates 70s/early 80s. Went down the rabbit hole trying to find a way achieve a similar tone live. Spent quite a bit of money and learned a thing or two, but to this day I have not realized the dream. About the closet I have gotten is running a DI into a mixing console and monitoring on headphones.
My observations: Musical instrument gear tends to reproduce a lot more detail in the mids than HiFi gear. HiFi gear sounds pretty in the mids, but it tends to smooth out them out, so there is less texture to the sound. To be fair, some of the texture can come from the MI speakers themselves.
Conversely musical instrument gear tends to be woolly and loose down low in comparison to HiFi gear. With HiFi, the lows seem tighter and more focused, but are also smooth.
I have played on some pretty high-end PA gear and none of it seemed to reproduce the same qualities I heard in HiFi gear. I have assembled a few rigs that achieved some of the qualities I was after, but not all.
For the proceeding I am basically saying that there seems to be some tangible differences in the way HiFi and MI gear speaks that is independent of frequency response.
The other factor is acoustics. One of the most frustrating aspects of playing live is how much masking you have to deal with. By masking, I mean other sounds obscuring the nuance and detail in your tone.
My understanding is when there are two sound sources playing the same frequency, you only perceive the louder of the two sound sources. So you have to deal with other instruments invading the frequency range of the bass and concealing nuance and detail.
Not only do you have to deal with masking from other instruments, I believe the indirect sound from your own rig can mask nuance and detail in your tone. The worse the acoustics are, the more severe masking tends to be.
Play live through a system that can reproduce that same tone as a studio monitor at an appropriate level, and I think the bass will tend to get lost. Bedroom tone syndrome. In order for your sound to cut through the mayhem, you have to find away to get the frequencies you key off to dominate in your ears. I do this by elevating my cab and aiming it at my head. I also tend to boost certain frequencies that I think sound good. I tend to run fairly lean lows, because to my ears more lows reduces clarity and focus. I don't claim that my tone on stage is great, but using this approach allows me to monitor at a lower volume, so my stage sound is not competing with the PA as much.
My stage rig is intended solely as my personal monitor and not intended to be a sound source for the main mix. I typically plug my bass into a DI. This way the audio tech gets a neutral/unprocessed signal from my bass that is easier to massage into shape
Probably one of the best things I ever did as a player is stop insistently chasing tone. I find it very rare to achieve what I consider to be a really great tone in a live setting. As a result, chasing tone tends to be distracting and frustrating. Better to spend a bit of time dialing in a reasonably good tone and then change your focus to playing. My point is you can probably get your tone to about 95% as good as possible within a few minutes. To achieve the additional 5% may require you to constantly fuss with the controls as the situation changes.
Unfortunately each situation is different, so a 95% solution one day may sound pretty good, while a 95% solution on another day may sound awful. So it can be tricky to recognize when you have done about all you can.
Having said that, @gtirard's suggestions are good... or maybe something like a Genzler bass array cab might get you there. But the so-called FRFR world is where you want to look. Six or eight of those JBL 708s would probably be loud enough for using in a live setting.
