Singing bowls

What are the best frequencies of resonation from singing bowls to get me into the Theta/Gamma stata while meditating. I’ve seen as low as 1200Hz and as high as 20000Hz. I remember one BALG magician, maybe EA, but there was talk about the right frequency bowls to get for quick transformation into the Theta/Gamma state to begin to see and become of the spike in brain energy.

Also, I would like to find a supplier form my magick needs to get high-quality resins., incense and candles that has been around and is going to stay around. Quality and consistency are of utmost priority.