Apparently literally nobody else has had this problem, because I didn't find any solutions searching the fora. Anyway, the problem is as stated. I have a TC Electronic Polytune, and it works great, except for one quirk: When working in poly mode (and ONLY poly mode), it doesn't pick up the low B on my 6er. It picks up every other string, but not the low B. I am fairly certain I'm in "Bass Mode," but the lack of an instruction manual and resulting trial and error makes it difficult to say for certain. I know I tuned it to Eb tuning, as I tune a half-step down. Do I need to tune it all the way down to Bb instead? Note: this only happens in poly mode. It picks up the Bb fine in single mode. But it's nice not to have to check separately.