Simon has laid it out nicely.

Reverb, however, in a room of nearly any size, is where should me of the space is created, after first choosing panning of the individual mono tracks. This is why you apply room reverb post fader, but plate and spring reverbs pre fader.

Drum kit panning is a matter of style and choice. Example, Rick Rubin’a mixes are often mono drum kit panned straight up the middle. If I’m not mistaken he did Tom Petty’s Wildflowers album mixed this way. (Quick stroll through 6 tracks confirms this), whereas hard panning is found on many of the other instruments on this album and it sounds absolutely fantastic.

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