Hi Mr. H,

That noise is called "chuffing" (add that to your audio/speaker lexicon) and in the Axiom subs, a special flared, irregular port (the "Vortex" port design) eliminates the noise.

I'll consult with Ian, Axiom's founder and designer; I think you could use a round insert of acoustically open-cell foam, which should break up the air flow enough to suppress chuffing without changing the bass loading of the sub enclosure. But yes, the chuffing is a byproduct of cheapo design.

Regards,



Alan Lofft,
Axiom Resident Expert (Retired)