You need to give Hsu a call. Do not play it anymore. There may be something wrong with the voice coil. Hsu will probably want to send you a new driver and have you return the old driver.
Another thing, playing videos like that is a great way to kill a subwoofer. Sine wave tones, which is what that video uses, are the most difficult loads on a speaker. And ultra low frequencies, like in that video, are extremely hard on the sub's motor. That video is the worst thing you could play on any subwoofer. Six minutes of continuous, ultra deep bass, zero dB full scale sine waves, just wow. If you had been playing that video loud and seared the sub's voice coil, Hsu could make a good argument that you voided their warranty through abuse, and I would not disagree with them.