Subwoofer Plug

I obtained some makeshift plugs for the ports on my B&W 803's at Wallymart, kids section. Those closed cell foam play balls work great. Just measure your port diameter and look for foam balls that are a bit larger. If you get a reasonably tight fit, they will seal air tight and that is what matters.

And I would not use a foam tube as you can make annoying wooshing port noise from the smaller diameter opening.

An air suspension design just means the driver is mounted in a sealed cabinet, ie, no ports. While the optimized cabinet design for an air suspension (dimensions, volume, etc) will be different than a ported design, plugging the ports on a ported design will get you some of the benefits of the AS design at the expense of low frequency response.

JohnnyB

Your are describing the properties of a driver optimized for a AS design. The OP does not have that. He has a ported design he wishes to convert with a plug. I only mentioned that he can get SOME of the benefits of the AS design (not all of them) by plugging his ports. He will also give up some of the low end frequency response he gets with a ported design.

Telling him to buy another speaker entirely is not that helpful IMHO.

There are numerous manufacturers (like B&W for example) that supply port plugs for their vented speakers. No one says this will convert their ported cabinets to an optimized AS design, but it may provide benefits. I myself do this to tighten overall bass response when using my HSU sub (which is also sealed) and adjust the crossover to compensate for the higher CP of the plugged B&Ws.

You can also find numerous speaker design guides that mention the use of the same driver in either AS or ported cabinets. Does not mean that using these mulipurpose drivers in a sealed cabinet is a bad thing. The driver does not have to optimized for AS to be called AS. That's nitpicking.