Ry Cooder most likely used open G tuning on “Smack Dab in the Middle,” with a capo at the 2nd fret to bring it up to open A. A source discussing Cooder’s playing on that track says he “often did” use open-G in that era, and another notes he commonly used open G for rhythm with a capo for different keys.

Tuning

  • Open G tuning: low to high, D G D G B D.
  • With a capo at the 2nd fret, that effectively sounds like open A.

Why this is the likely answer

The track was recorded on Chicken Skin Music , and the available session info identifies Ry Cooder on both electric guitar and slide guitar, which fits his usual open-G/open-D slide approach from that period. A separate Ry Cooder tuning discussion also says he mainly used G and D tunings, with G being his rhythm tuning and D being his slide tuning.

Practical takeaway

If you want to approximate the sound, start with open G and add a capo on 2. That’s the closest documented setup tied to Cooder’s style on this song.

TL;DR: Open G, capo 2 is the best-supported answer.