Interesting comment "much of the music we listen to was mastered on them." well actually no, there was a time in the early ninties that some studios were using Proacs.
Most of the popular recordings rock and jazz were and are mastered on ATC, and if you look at ATC's website you will see just how many people are using ATC professionally and they have been the dominant force in studio's for the last 40 years, sure there are others competiting in this market, ADAM, Myer and many others.
The Yamaha NS 10M was the dominant monitor in the 1970's thanks to Bob Clearmountain's endorsement and by today's standards the NS 10M was a horribily colored speaker/
As per Proac vs Monitor vs KEF these are all great speakers and differ in tems of how they present the infomation.
As per Proac's playing the music and sound effortless doing it all three of these speakers will do the same thing.
It will come down to Ribbon tweeter, Proac, which tend to be extremely detailed, vs AMT, Monitor Audio's, which have a slightly more laid back top end compared to a true Ribbon vs the seemless quality of having all drivers made out of the same material in the KEF, plus the soundstaging capabilites and imaging that come from a true point source.
We would say this is a hard choice all these speakers are excellent comes doesn to presentation, price, styling.
Dave and Troy
Audio Doctor NJ
