@jtwrace Thanks for posting this. I own a pair of Rythmik subs and couldn't be happier. Brian Ding makes a great product at very reasonable prices. I've add this video to my listening queue and looking forward to hearing what he has to say.
Rythmik Audio on The Intellectual People Podcast
In this episode Brian Ding speak about how he came to develop the Rythmik Audio Servo Controlled Subwoofers and the importance of Thiele parameters.