This one blows my mind. I must have replayed it two dozen times, trying to think of one word but to hear the other one. It just can't be done. There's no in-between, no fuzziness. When I think of "brainstorm", the word is unequivocally that. I even looked for "brain needle" or "green storm", but nope.
I can do "brain needle" or "green storm". Just like Yanny / Laurel, I believe the lower voice (brainstorm) is what is intended to be heard. The distortion artifacts in the higher frequencies just happen to match up with "green needle" - super interesting.
To me, the "Laurel" "Yanny" wasn't as interesting, because I could clearly hear both at the same time in different registers. But I really like this example because I can't hear "brainstorm" and "green needle" at the same time - it really seems like my brain shuts the other one off once I start listening to the audio.
I had the same experience when using headphones. But then I showed it to my wife, through the crappy phone speakers, and she could only hear green needle, no matter what. And I... green storm. So quality matters too.
After listening to it a few dozen times, I'm fairly sure that it actually says Brainstorm and that "Green Needle" is an artifact of the awful speaker. There seems to be some sort of reverberation happening.
This is great because I can hear both very easily while in can only hear Laurel moooost of the time. Here it's much clearer that when primed for "storm", "nee" is at most interpreted as a low deformed echo of "-ain", and when primed for "needle", the low sounds of "-rm" just disappear at the end. Thanks for the link.