The acoustic guitar ... tuning, these possibilities multiply, as suddenly we’re able to access voicings that are impossible – or even painful – in regular tuning. We can use the open-tuned ...

Once you've whetted your appetite for open tuning experimentation, your acoustic guitar having long forgotten the vanilla pleasures of EADGBE, maybe it's time to try open Aadd9 (EAC#EBE).

The Tenor Guitar Gathering includes ... from six-string use Chicago tuning.” Tuning in fifths with only four strings makes chords sound more open, with less redundant notes.