T1 ToneMatch® Audio Engine / Tuner
If you are experiencing difficulties with the tuner, here are some points to check.
- *CRITICAL*. Make sure the CH Edit button is pressed on the Channel of the instrument you are trying to tune.
- Make sure your instrument is gain staged correctly.
The tuner needs a good strong signal (at least solid green) to lock on to.
- Take off/bypass any effects that affect your instrument before the signal enters the T1®.
Any modulation effects will mess things up.
- In all of our testing and experience here we have found the tuner to be as accurate and reliable as other high quality stage tuners. The T1 tuner is fairly 'fast' in terms of tracking speed. For example, typically, Boss tuners have more 'averaging' and slower tracking speed. The needle moves up to the note you are tuning slower, but is more stable once you get up there. Another example - Peterson tuners generally track faster. They go up very fast to the note, and move around more once you get up there - this is because the instrument is actually slightly varying pitch. The tuner is tracking this behavior correctly. Both Peterson and Boss make awesome, super accurate tuners, its just like the difference between a Strat and a Les Paul...or a Porshe and a Benz.
- The T1 tuner, as I said, is faster in its tracking, and this may take some getting used to at first. It took me a little while to become accustomed to bench tuning my basses with a Peterson strobe tuner after using a Boss for a few years.
- "The internal send for the tuner is Pre-FX" 
And a hint from Bill-at-Bose
- You may already know that the ubiquitous hum you hear, that can be caused by cable grounding problems, lighting dimmers, ground loops, etc., is based in the U.S. off the 120 VAC line.
- The line cycles at 60 Hz, you can usually pick up multiples of it: 120 Hz, 240 Hz. That's right between an A and a B-flat.
- Here are the frequencies:
- A#2/Bb2 116.54 Hz
- B2 123.47 Hz
Hum louder than your note will confuse your tuner for sure.
You hear that note everywhere you go in this 'civilised' world, from fluorescent lights to refridgerator motors to your PC hard drive.