Once you can get these first two overtones on the low B flat fingering you can start feeling really good about your progress, congratulations!
Now we’ll do the exact same thing on the next few notes following the low Bb. As you’ll see below, the same exercise starting on the low B natural, C, C#, and D.
Say Hello to the 3rd Note of the Overtone Series – 3rd Octave Bb
For this exercise you’ll notice that the first three notes are all the same note (Bb) in 3 different octaves: