I am lucky to live near Austin, so I was able to pick up my dual subs directly from his warehouse and got to meet the owner Brian and got all the info I needed. Couldn't be happier with the service and my F-12s. That was years ago. Got introduced to them through Ascend Acoustics. They have a special relationship going. David Fabrikant, the owner, is an outstanding individual. I no longer have his raal towers since I wanted to go larger in my house of stereo, but they were amazingly good for their size, specially the bass and of course the clarity of the treble with the raal tweeters. I guess I wanted to give them a shout-out. A couple of great brands that mostly go under the radar because they don't advertise.
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.