I was enjoying my Polk RTA 12 speakers tonight and I began wondering what technical facts and fancy there are to know about its passive radiator woofers. Normally my attention is captured by their tweeters' wonderful performance, but tonight I noticed how well the bottom cabinet was doing its job. No, it didn't go as low or as loud as the KEF 104.2s standing next to them, but the difference wasn't extreme, by my senses.
All this bass from a passive drumhead that magnifies the bass from a pair of six-inchers? If this is such an effective idea,why don't more speaker manufacturers use it? Size, I'd guess. There are some of the largest woofers I see in high-end audio, outside subwoofers.
I'm new to the Polk world, and not that grounded in the engineering. But if someone wants to expound on this, I'm all eyes... the Polks have my ears.