http://www.avguide.com/review/the-rel-gibraltar-g-1-sub-bass-system
January 9th, 2013 -- by Jim Hannon
Source: The Absolute Sound
The Sonus faber Amati Futura loudspeakers were delivered with one REL Gibraltar G1 sub-bass system. While external subwoofers heretofore have not been my cup of tea because they can muddy up the main speakers midbass and midrange, the G-1 is different. The REL is designed to mate seamlessly with high-performance main loudspeakers, and does so admirably. However, one must have a light touch with its settings (lower is better) to achieve its beneficial sonic gains.
REL Gibraltar G-1
The G-1 sports a massive 12" long-throw carbon-fiber driver capable of an excursion of 1-3/4" in an attractive, extensively braced, sculpted cabinet, as well as a high-quality internal 600W class A/B MOSFET power amplifier. Its terrific disc-shaped IR remote control lets you adjust volume, crossover frequency, and phase from the listening position. This critical functionality allows one to easily dial the G-1 in (or out).
Although I didnt use them, it also has features for home-theater applications (HI/LO level, .1/LFE level). For comparison purposes, I easily switched the G1 out of my system by simply disconnecting the G-1s Neutrik Speakon connector on the back of the REL, thereby breaking the connection between the subwoofer and the speaker terminals of the amplifiers driving the Amati Futuras. (Mute your preamplifier before doing this!) I vastly prefer RELls connection approach since the main loudspeakers are essentially untouched by the G-1.
While one would expect the G-1 to add more extension and power to the Amati Futuras deep bass, and it does, the effect is not as dramatic as you might think because of the Futuras very fine low-end performance. On the Pierre Verany recording of Bachs famous Toccata and Fugue in D Minor the lowest pedal tones of the organ had somewhat more extension and weight, but what was most surprising were the gains in soundstage expansion and hall ambience retrieval, two of the most formidable of the Futuras strengths. On well-recorded albums, the soundstage expanded to the side walls, more of the hall was evident in front of the speakers, and the sound was more palpable with greater air and presence. On Schubertiade [Harmonia Mundi] neither the marvelous natural timbre of Judith nelsons voice nor Alfred Prinzs clarinet was affected by the G-1. Thats a tough test that only the best subwoofers can pass.
For those who want even more air and low-end impact, the G-1 can be daisy-chained with additional G-1 units in stereo pairs or vertically stacked towers. I plan to audition the Amati Futura with multiple G-1s in Sumikos listening room. But even a single G-1 yields substantial, albeit subtle, sonic benefits without causing any harm or drawing unwanted attention to itself. Thats the best praise I can give any subwoofer/sub-bass system!