Dear Nic: Hi from this Bob. Please keep in mind that to a great extent, brand and model preferences are personal opinion. We can be as objective as possible, but ultimately we choose by our ears. And your ears are not my ears.
One of my clients doing mixing, is using an ATC pair for mixing. I had him install a Lake processor to reduce a high frequency peak in that model. It’s been years so I don’t even remember the model number. I know a number of high end mastering engineers who swear by certain ATC models for mastering. I am not familiar with which models they’ve chosen, sorry to say. What I’ve heard has been nice, but not my cup of tea.
I have a pair of Kii 3/BXT in Studio B for mixing. They are superb, among the finest quality speakers on earth. Bob O. says that extremely flat monitors could produce deceptively good mixes, but so far in two+ years of mixing we haven’t had a client say that some instrument is too low in the mix. They are the only speakers in the mix room… I don’t switch to “alternative mixing speakers”. I do have a pair of Audeze LCD-4Z (or 4M, I forget) headphones in there, and sometimes use them as a headphone reference. The Kii 3/BXT would make excellent mastering speakers in a not too large room. I highly recommend them and would be thrilled with them without question in my mastering room, Studio A. Just not able to play them quite as loud as my Dynaudios, which is the only possible consideration about the Kiis.
In Studio A I have a pair of Dynaudio M5P, mastering monitors. They are over 8 feet tall, go down to 27 Hz -3 dB by themselves. Most people would consider that more than adequate, but I have supplemented them with a pair of JL Fathom F112 subwoofers that extend the response to 17 Hz flat and 15 Hz -3 dB. I discovered after purchase that the Dynaudios are a hair bright at the top (which seems to be a tendency these days 🙁 — but it wasn’t a problem since I perform linear phase correction with Acourate Convolver for the best correction although with considerable latency, and with the Grace M908 Monitor controller for zero latency.
Can you get away without correction? Yes, I remember the classic Dunlavy speakers sounding superb without any correction. But not every room is perfect and a little tweak doesn’t hurt. I treat mastering with great responsibility so if I hear a nit and I can measure an anomaly that corresponds with the nit — I try to fix the nit :-). It keeps me confident in what I’m putting out.
Can any loudspeaker/room issue be made better with digital correction? With the right software/hardware, yes. Both Acourate and the Grace have extremely versatile and high resolution EQ available.
Hope this helps.