These are amazing! They work pretty well still without headphones. If I place my body in between some good stereo speakers, I can still hear/perceive the third wave being produced from the combo of the two pure tones being played from the L and R channels. Simply genius.
Most likely you're hearing a monaural beat -- the waves will have mixed in the air before they enter your brain. But, some people say those are just as effective as binaural beats. Whatever works 😉
Zen Loops