I've always been impressed with "Achilles Last Stand" . The impression I take away after listening to that song is that there were so many guitars doing so many things. Especially as a guitar player, there is a feeling of an orchestral approach to the use of the instrument. So, when I was recently confronted by the problem of mixing a lot of guitars I thought i'd examine what was done there - panning wise. Hats off to Keith Harwood, at Olympic Studios who engineered "Presence" the album where the track sits at number 1.
I'll have a full analysis in the future, I actually started digging into it and with the second markers and form & analysis work that I think would be informative there was no way I could get the depth I needed in the time I had so I added the work I had done to the long burn pile.
So - this will be at a high level. The near constant of the song is a hard pan, nearly doubled guitar. The more fleshed out of the two doubles is on the hard right. I say "Near Constant" because the two sides occasionally are used as a dynamic build on motif restatements. Where the first statement of a motif comes in on the hard right, followed by adding the double on the left the second time through.
Another note about this double which is a cool orchestration twist. The left pan ends up playing a simpler and more sustained part, so you get this kind of monophony that not only is effective from a sound thickening perspective but also has a musicological hook to ancient music which ties into the mythological frame of the song (even though it is apparently semi-biographical from Plant).
What I hadn't recalled until my recent listening is that effort of pairing that is near constant as a double is also used in all of the guitar orchestra treatment. So when we have a new musical idea stated from the orchestra - it is typically done in pairs - a high tenor line and a lower baritone line. This I think adds to the cohesion of the song - because we are hearing again, now in a different context a pair of guitars, its too consistent to be coincidence. It also helps the solo truly stick out as a single (very loud) voice.
So - on to the panning, the main event. The panning is interesting though it ends up being very close to center on the right and then off kilter on the left side. The near center guitar is the higher, tenor line and the lower of the two is the off kilter pan. Not only that the off kilter pan is a bit louder as well. That serves two purposes - it helps the lower register speak a bit better, as we will have less problems getting the higher pitched sounds processed in our ears but it also - more importantly emphasizes the imbalance of the stereo field. I think it is this that creates a musical feeling of drama that echoes the quest and conflict feeling in this song. This psycho-aural impact is one of imbalance and exploration - an uneasiness and lack of sure footedness (which in the case of Robert Plant's injury that kept him in a wheel chair was quite literal).
Here is a pretty rote diagram showing what I am talking about:
I think what I take away from this is the power of panning to not only find a mix space for an instrument - a place where it can be heard and contribute but that panning choices that we make in songs can assist the narrative of the song in subtle ways creating the ground on which the ideas, conflicts and resolutions within the musical and lyrical are laid forth.