About fifteen years ago I was working in a studio in London mixing an album for a band. The studio had a lovely G-Series SSL console with a Klark Teknik DN60 spectrum analyser on the meter bridge.
My mixes were sounding great and I was perfectly happy with them.
Then the studio assistant offered to play me some mixes done by world famous mixer Bob Clearmountain, done in the very same studio just the week before. I was blown away - they sounded incredible and they made my mixes sound weak and flabby by comparison.
The other thing I noticed was that, when my mixes were playing, the spectrum analyser reproduced a kind of “n” shape, rolling off at the top end at about 12khz and at the bottom end at around 100hz.
During Bob Clearmountain’s mixes, however, it showed an almost perfect straight line except for a slight dip around 1 - 2khz - which promptly disappeared as soon as the vocal came in. His kik drum went down to 20hz and his hi-hats went up to 20khz. It was astonishing.
So, I decided to go head-to-head with the great man and started filling in the gaps, wodging on great peaks of EQ down the bottom and up the top with a close eye on the spectrum analyser. After a few hours of intense work and concentration I’d done it - my mix looked exactly the same as his.
Unfortunately, it sounded fucking terrible.
I discovered shortly after that Clearmountain had actually asked to have the spectrum analyser disconnected while he was working because it distracted him - his tracks only looked good because they sounded good. I learned my lesson and vowed to mix with only my ears from then on.
I’m not saying they don’t have their uses - finding out the exact problem frequency in a sound so you can dial in a precise notch filter for example - but I think if you come to rely too heavily upon them whilst mixing they have the potential to do more harm than good.