Despite the countless times over the years that I've listened to D&C it's only the past few months that I began to notice, during the main solo a ghostly, shimmering chord-like sound. It's very very low in the mix, but there. To my ears it sounds very like the strings, above the nut being strummed in one stroke, but it's not that since there seems to be distinct chords being played. I had wondered if perhaps Page has used a capo say on the 12the fret to get this effect, or maybe had ultra-speeded up the tape of a regular chord. Anyone else tuned into this 'lost' voice of this mighty Zeppelin track?