Mystery solved (kinda). Look at these 3 fan cam videos the sound and all mics are even. You can hear Jin, Jimin and Taehyung without an issue in the same parts of the broadcast that went unnaturally low.
The Broadcasters (Hulu and Disney+) likely tried to mute the audience to enhance the microphone sounds. This is usually done via a dedicated broadcast audio engineer who will slide the crowd faders up/down significantly. Plus, dynamic microphones make it easier, too. There isn't usually a problem with that method.
The second, which has gotten popular over the last few years, is using AI to do it. But what happens is, it can blend everything together messily by accident, creating low parts and extremely high parts of a sound -- so it's incredibly uneven.
Not saying which method they used or what happened -- but whatever the Broadcasters did to isolate the mic sounds ended up messing with the main audio feed and there is a strong chance that that is the reason the sound was so off for the broadcast.
I've watched over 3 dozen fan cams and the sound is fine in all of them.
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