I think it goes beyond music you play. The vibes you bring around your plants affects them also. Its just a simple phenomena called RESONANCE. Everything vibrates, and two different vibrating bodies can resonate with each other. A lot of older growers say that their mood affects theirs plants and they say it seems as though the plants recognize their presence. I'd like to say I've seen it myself when I visit my plants. Right now I've separated the plants that are doing good and the ones that aren't doing so well. It looks like the two that are doing well are growing in synchronicity with each so I want those two by themselves to see what they do. Metaphysics affects everything. BTW, great info on the quartz crystal, they use a quartz crystal oscillator to set the rate or frequency at which an electronic device runs.

I'm not into the stuff but in magic or metaphysical healing they keep crystals around and speak positive energy into it with the idea that the positive energy will resonate back.