That article seems to say that this technique works better with LED lamps vs. incandescent bulbs. I wonder if they're talking about direct line of sight to the

That article seems to say that this technique works better with LED lamps vs. incandescent bulbs. I wonder if they're talking about direct line of sight to the LED chip. Most of the LED "bulbs" in my house use a frosted plastic housing around the LED chip, which I would guess to interfere with the sound recovery.