E Flat or D Sharp

Stratavarious

Tune in flat keys.. flats

Tune in sharp keys.. sharps

I use Eb when describing down tuning as it involves going down.

Simple

viz

Also:

major keys: natural or flat.
minor keys: natural or sharp.

(The keys with 6 have a sharp and a flat version, and the keys with 7 break this rule, but there's a more convenient key with 5 that adheres to it.)

Whistler

@rickd2112a ;, I saw this and thought of you.

strtdv

D sharp and E flat used to be different notes, so presumably the convention is a hangover from that

Whistler

strtdv said:

D sharp and E flat used to be different notes, so presumably the convention is a hangover from that

Yes, a hangover from about 1680 when temperament, and specifically well-temperament, were introduced.

There is a fascinating video of James Taylor explaining exactly how he tunes his guitar:

https://www.youtube.com/watch?v=V2xnXArjPts