I have been playing double bass now for a couple of months. I recently bought the Tonal Energy App for iPad for both tuning help and to watch a bit while I practice scales and arpeggios. Granted, the app measures semitones in 100ths (and even 1000ths?!?!), an extremely high measurement. Still I'm shocked at how infrequently I'm actually playing the notes correctly. It's very humbling. The higher percentage I'm off is that I'm flat. I guess this is understandable considering that it's probably better to be slightly flat than slightly sharp. Slightly sharp often has a distinctly unpleasant sound, while slightly flat is easier hidden. I'm thinking maybe it's good for me to put note markers on the bass where the frets would be. Any advice on this point would be greatly appreciated. I have a teacher; bbut probably not for much longer.