Hello All,
Great to see all the interest regarding our new subwoofer. I have a few comments regarding some of what has been discussed. This subwoofer is not any more dangerous to own or operate than any other high output sub on the market. The subwoofer has a grill option to protect against accidental or purposeful contact with the driver. Yes, the driver is tremendously powerful, but not to the point of causing some type of bass explosion resulting in destruction of the subwoofer that would potentially cause bodily harm or injury as some have insinuated. There have been hundreds of hours of extreme SPL testing performed with this subwoofer while developing the driver and enclosure. Several drivers and a single test enclosure have sustained minor damage in the process, which resulted in further improvements to the driver and enclosure, but sadly nothing as dramatic as what has been discussed. If the subwoofer was capable of explosive destruction, it would make my job incredibly exciting! Just like car crash testing, it is my job to test this product to the point of failure to find out what the subwoofer's limits are. I can definitively tell you, that is not an easy task to perform with this sub using our 4000W+ capable amplifier. I have yet to burn up a voice coil on this driver even when the subwoofer has been continuously pushed over and over again during extreme testing that an end user of the subwoofer would likely never be able to replicate even if they were purposely trying to burn it up. Also, there are no power handling problems at all using neodymium magnets in this open motor structure . Yes, large ceramic magnets used in a motor structure are capable of dissipating more heat, however, because of the enclosed nature of ceramic motor structures (how they cover the voice coil bellow the top plate all the way to the back plate) , they need to be able to dissipate more heat due to being subjected to more heat from the voice coil. The open motor structure our driver uses does not require substantial heat dissipation by the magnets and is ultimately capable of higher sustained voice coil temperatures (thermal power handling).
Why use a sealed design over a vented design for the subwoofer? Read Matt's explanation posted above. He explains it very well. Sealed subs are inherently more effective at producing extreme low frequency (infrasonic) output in reasonably sized enclosures. For those that are interested in a vented version of the 21" sub, we can produce a vented version of this subwoofer which requires a 19 cubic ft enclosure (Fb=16Hz), but is capable of producing 125dB@20Hz and 113dB@16Hz, passing CEA2010 distortion levels. At 12Hz and below the sealed 21-FS/R has more output in a much more reasonably sized 6 cubic ft enclosure.
Regarding how the 21-FS/R performs/sounds, I look forward (like all of you) to reading Gene's opinions in his review. All I can say from my perspective as the engineer behind the product, is this; I have heard a number of very good subwoofer systems from various manufacturers over the 30 years I have worked in the industry, but as of yet, I have never heard/experienced another subwoofer quite like this.
Shane Rich
Technical Director
RBH Sound
