When I wrote
The Mixing Engineer's Handbook 
in 1998, I was lucky enough to get to interview the Godfather of recording engineers,
Bruce Swedien. During our interview, Bruce talked more about the philosophy of mixing rather than the nuts and bolts. Here's an excerpt from that interview, where he talks about hearing in "colors."
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Is your approach to mixing each song generally the same?
I’ll take that a step further and I’ll say it’s never the same. And I think I have a very unique imagination. I also have another problem in that, I don’t know what the hell it is, somebody told me once, I hear sounds in color, with colors in my mind. And I can frequently do EQing and so on and check the spectrum of a mix or a piece of music, if I don’t see the right colors I it, I know the balance is not there.
What do you mean?
Well, low frequencies, low sounds appear to my mind’s eye as dark colors. Black or brown. Bass can usually be black or brown or dark purple. And then high frequencies are brighter colors. Extremely high frequencies gold and silver. And so, it’s funny, but that’s, that can be very distracting. Drives me crazy sometimes.
There is a term for it, I don’t know what it is. [It's called "synaesthesia"]
What are you trying to do then, build a rainbow?
No, it’s just that if I don’t experience and see those colors when I listen to a mix that I’m working on, I know that there’s either an element missing, or that the mix values aren’t satisfying.
How do you know what proportion of what color?
That’s instinctive. Quincy [Jones] has the same problem. It’s terrible! Drives me nuts! But, it’s not a quantitative thing. It’s just that if I focus on a part of the spectrum in a mix, and don’t see the right colors, it bothers me.
I have a feeling it’s a disease, but people have told me it isn’t.
How do you go about getting a balance? Do you have a method.
No, purely instinctive. Another thing that I’ve learned from Quincy, I think, that started with my work with Duke Ellington, is to do my mixing reactively, not cerebrally.
How do you mean?
This is when automated mixing came along, I got really excited because I thought, “At last, here’s a way for me to preserve my first instinctive reaction to the music.” And the mix values that are there, rather than, you know how frequently we’ll work on a piece of music, and work on it, work on it, and we think, “Oh boy, this is great! Wouldn’t it be great if it had a little more of this, or a little more of that.” And then you listen to that in the cold gray light of dawn and it sounds like shit. Well, that's when the cerebral part of our mind takes over, pushing the reactive part to the background, so the music suffers.
Do you start to do your mix from the very first day of tracking?
Yes. But, again, I don’t think that you can say any of these thoughts are across the board. here is certain types of music that grow in the studio that don’t, you go in and you start a rhythm track and you think you’re gonna have one think, and all of a sudden it does a sharp left and it ends up being something lese. While again, there are other types of music where I start the mix before the musicians come to the studio. I’ll give you a good example of something. On Michael’s History
album, “Smile, Charlie Chaplin.” I knew what the mix would be like two weeks before the musicians hit the studio.
From listening to the demo?
No. It had nothing to do with anything except what was going on in my mind because the orchestra, the arranger and conductor, Jeremy Lubbock and I had talked about that piece of music. And the orchestra that we were gonna use, it’s a big orchestra, and I came up with a studio setup that I had used with the strings of the Chicago Symphony many years before at Universal. Where the first violins are set up to the left of the conductor and the second violins to the right, the violas behind the first fiddles and the celli behind the second fiddles, which is a little unusual. So, I had that whole mix firmly in mind long before we did it.
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via phone. Supposedly Michael warmed up for several hours and had a voice lesson before almost every vocal recording session. Of course, we all know the results.
."
saying before they began the Thriller recording sessions, "We've got to find a way to get people back into the record stores." What everyone seems to forget is that from 1979 to almost 1982, the record business was in a very bad recession. Disco had just burned out, there was no new trends on the horizon, and record sales were declining fast as a result. It seemed almost as bad as it is now, except for the fact that several things came to the record labels aid - the CD, MTV and Michael Jackson and Thriller.
and 
