RBH Sound’s Unrivaled 21-SF/R is a 300+ lbs. monster that uses a 21” carbon fiber driver powered by a 4,000 watt amplifier. This bruiser is so powerful that it forced us to create a whole new category of performance for our Bassaholics room rating called Maximus. This 21” behemoth uses a carbon fiber cone that attaches to a massive cast aluminum basket with a correspondingly large half-roll rubber surround. It has a staggering
38mm of Xmax (one-way linear travel) and 50mm of Xmech (one-way mechanically limited travel). The motor uses eight neodymium slugs for the magnet since iron ferrite would have been too large and heavy to support within the enclosure. Even though neodymium is very expensive, RBH did not want to compromise on their performance targets for the 21-SF/R, and the resultant magnetic flux is tremendously powerful at
35 Tesla Meters.
I just got this beast integrated into my theater room and getting flat 10Hz in-room bass response with little boost needed. I am literally measuring bass down to the limit of my microphone (5Hz).
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Read: RBH Sound 21-SF/R 4kWatt Subwoofer Overview
Note: This is the official thread for the RBH 21-SF/R subwoofer and I will be showing measurements and linking up the formal review once completed. Bassaholics will want to bookmark this thread.