Why don't you call SVS and see if they'll send or sell you a plug? Your model may not have come with one, but all their ported square subs come with foam plugs now to adjust the bass rolloff profile.
Subwoofer Plug
Howdy, how to do you get or make a good subwoofer plug? I have a pair of SVS subs that I'd like to plug and, given that I'm trying to blend subs with Maggies, any sub I get in the future will either be sealed or I would like the option to at least trying a port plug. Problem is that unless it comes with one I have zero idea what to do. I suppose I could throw my dirty laundry in there, but that doesn't seem optimal somehow..... I should probably stick to clean clothes. ;)
Showing 3 responses by johnnyb53
Sorry Dhl93449, Eldartford had it right: An air suspension design requires a sealed enclosure, but not all sealed enclosure speaker designs are air suspension designs. The bass drivers made today usually come with the specs to determine the enclosure volume and port length and diameter for a ported speaker and the enclosure size for a sealed design. The sealed design is *not* an acoustic suspension design because the woofer's ability to make excursions and return to neutral is entirely dependent on the cone stiffness and magnet strength. In a true acoustic suspension speaker, the speaker cone and magnet strength are significantly reduced along with the enclosure size. The sealed air in the enclosure then supplements the magnet and suspension to control cone motion. In a standard sealed enclosure, which is much larger relative to the woofer diameter, the sealed air does not significantly contribute to the cone excursion and restoration. For example, a standard 10" woofer today might require a 4.8 cu. ft. enclosure if sealed. However, the true acoustic suspension designs of the '60s (e.g., AR3a, KLH, Advent, etc.) were mounted in a 2.3 cu. ft. enclosure and produced true low-distortion bass down to around 30-33 Hz. The floppy suspension and thin cone lowered the free air resonance of the woofer to make this possible. |
I never told him to do any such thing. I was addressing Dhl93449's assertion that acoustic suspension and sealed enclosures are the same thing. They are not. I *know* the OP has a ported enclosure. Acoustic suspension isn't really any part of the OP's discussion. But plugging the ports changes the damping, causes the bass rolloff to happen at a higher frequency, *but* makes the rolloff occur at a gentler slope. I'm all for him trying it. I was just trying to address the misconception that sealing the enclosure turns the sub into an acoustic suspension design. It does not; but it turns it into a sealed enclosure, or at least raises the damping significantly. |