Will Roadie 3 tune an extended range guitar, like for instance a 7 string guitar?

Roadie 3 allows you to tune all sorts of string instruments including electric, acoustic, classical, and steel guitars. This also includes extended range guitars, 7, 8, and 12-string guitars, in addition to ukuleles, mandolins, banjos, and many more.

If your instrument does not have a standard number of strings or is not built into the Roadie 3 itself,  you can always create a custom instrument on the Roadie Tuner mobile app and then sync it with your Roadie.