It's hard to explain, but there's heavy turbulence at the port. The rug prevents that.
It's a port, driven hard and at low frequencies where the port takes over in tuning, there will be turbulence at high spl's.
The old video you linked was a driver issue not the port. In Erins video at 18.50, while sitting right next to it, he clearly states there is no noticeable port chuffing to be heard.
Also, these subs are supposed to be dsp tuned internally as to not overdrive the driver.
As
@abdo123 stated, using the rug as you are doing in your photos, is changing the tuning of the sub.
I switched it from THX gain/EQ to +15db/Extended EQ & use AVR sub channel -6db for movies -12db for music. Seem to have opened up more the sub amp. It could be burn-in, as I think it sounds better on day2.
This all sound a bit wonky. Have you read the manual on how too properly setup this sub?
1) You need to set the crossover THX toggle switch to off, then control the crossover from your AVR.
If you leave this on, you are now using the crossover built into the sub and the crossover from the AVR, that's neither good nor correct.
2) With regard to Extended or THX mode toggle, extended will give more output but with more distortion. So experiment accordingly.
3) With the level adjustment, turn it all the way down counter-clockwise until you hear a click. That will put it in the THX position, which is supposed to be 0dbs level.
4) Now you control the sub vol levels with your AVR.
Try setting it up as intended and see how that works out. If you still have issues, throw everything out the window and just set to what works, but don't expect more out of a 10'' with your current room size.
