I perfectly understand the differences between masking and canceling, and understand why "noise cans" work how they do with random white noise. Which is the very reason why I mentioned "intelligent" white noise (which really doesn't apply here, I understand) but more importantly the second system (which I was wrong to call a masking system, as it really is a canceling system).
How it works is that it reads (based on the measurement mics) the sound from whatever the noise source is, and generates an off phase signal which is then dsp processed and put out through the different speakers in the room in some proprietary way so as to cancel the noise being emanated from whatever it is that is making the noise.
I do not see how this is different from what they want to do in the "Reduction" thread, although arguably it would be exceedingly difficult to use one for "anti acoustical badness" as you would technically need a system in every single acoustical reflection point.
That is, of course, unless some amazingly complex signal dsp and a distributed system of advanced digital steerable arrays was conceived which could account for every reflection spot in the room, and could fire sound waves at each location (or groups of) in exactly the right time and phase to cancel the waves.
Anyone up for a science project.
Karl "But seriously, I don't get how the system is not a canceling system" P