Read loads of reviews over the years that mentioned it. Know it stands for "Acoustic Resistive Matrix". Seen pictures of it inside REL subs. Don't understand it. Any kind REL owners out there who can tell me how it actually works (principles would be good, actual parameters would be better). And yes, I know it's probably patented, but Mr Lord doesn't really have much to fear from me. Any advice would be gratefully received. Cheers, Stevo (Bits of Linn and Arcam plus a BIIIIG Sony SA-WX900 Sub).