I've seen this same chart years ago.
This is used for forgotten tunings to find the frequency, for example tuning in Open E 5 you tune the 6th string to E as in standard tuning.
The A string also gets tuned to E so how did we figure out weather to tune the string up or down is by reading the frequency on our tuners,
Old tuners didn't tell us if we were tuning to E or A we just aimed at 440,
So what we figure out was to turn the A down to E the D up to E the G down to E the B to a B and E tune to E .
This tuning sounds like a Sistar
And was used by the Doors & Cosby Stills and Nash songs throughout their bands history Steven Stills work in Open E 5 is extraordinary.
Remember 1 to the 5th the original bules players tunings came from Cigar Box Guitar's . In Cleveland Ohio the Rock and Roll Capital of the World
We all love MGB Guitar's I've been playing my Red Brick House around & people want one for themselves.
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