A#3 is also known as Bb3
A#3 is a nice low tone, easy to meditate to. When choosing a crystal singing bowl, you need to find a sound that resonates with you. We are all unique, so everyone can react differently to a specific tone.
If you like the A#3 you might consider adding D#4 for grounding tones (Perfect 4th), F#4 for total relaxation (Perfect 5th) or G4 for expanding tones (Major 6th).
Not sure what note is the lowest in the third octave?
This is the order of the crystal singing bowls, lowest to highest in the third octave.C3, C#3, D3, D#3, E3, F3, F#3, G3, G#3, A3, A#3, B3