ScanSpeak 23W/4557T-02 Revelator, 9" Aluminum Cone Subwoofer, Black Cone
Same model as 23W/4557T, except with a black cone.
The Scan-speak 23W/4557T is a very high end subwoofer, designed to be used with a passive radiator in a small enclosure. This sub has a very rigid aluminum cone, low loss rubber surround and cast frame. The passive radiator is similar, but with a weight attached to the bass of the cone. The 23W/4557T is using the SD-1 motor system. There are gold plated binding posts and the woofer is covered by a decorative rubber cap.
Frequency response with the passive is down to 25Hz. One cubic foot sealed has an F3 of 33Hz.