As some of you may remember, chesserroo has been complaining about the port chuff noise from his EP350 during certain very loud, bass-heavy passages.
The other day, I finally "succeeded" in inducing an audible port chuff on my Hsu VTF-3, an allegedly more powerful (and pricier) sub than the EP350. It was with a recording of Saint-Saens Symphony #3 the "Organ" Symphony, 2nd Movement, included in the Boston Audio Society test CD #1.
The organist uses the 16Hz low-C pedal tone quite generously in this recording, and that tone induced a subtle but audible port chuff on my VTF-3. I think it was audible because those passages were otherwise very quiet. I don't know the peak velocity of the air coming in and out of the port during that passage, but when I put my hand at about one foot from the port, it felt like a large blower shooting out the air flow. It WAS powerful!
So... I guess that some port chuffs are a more or less inevitable accompaniment of ported subwoofers. Given that it cannot be completely prevented even in the VTF-3 (arguably one of the "kings" of under-$1000 subs), I guess if you want to completely avoid port chuffs, you probably have to go with a sealed sub -- and of course, high-performance sealed subs are quite expensive.
chess, do you feel better now?