Subwoofers — System Audio Silverback Sub Duo

The Silverback Sub Duo is a bass expansion unit from the Danish manufacturer System Audio A/S, designed only as a partner for the Silverback Sub Solo wireless subwoofer. It is not a standalone product, as it contains no amplifier of its own and draws its power from the Sub Solo. The maker lists it at EUR 899, and System Audio explains that a pair of smaller subwoofers distributes low frequencies through a room more evenly than a single big unit.

Key specs that matter

A single 8 inch Silverback Vulcano woofer sits in the cabinet, the same long-stroke driver with two voice coils used in the Sub Solo. Its rated range spans 17 Hz to 250 Hz. The enclosure measures 42 cm wide, 31 cm tall and 20.5 cm deep, identical in size to the Sub Solo, and comes in white satin or black satin. The signal and drive connection is a 4-pin mini-DIN socket, and a 10 m interconnect cable is supplied. Other contents of the box are rubber feet for floor use, a power cable, a fabric front grille and a quick start guide.

Engineering and use context

The Sub Solo carries four Class D amplifier modules of 150 W each, and two of them are reserved for the Duo and fed out through a dedicated connector. This means the pair works as one system, with level, crossover, distance and phase handled for both units through the SA Cockpit app on the Sub Solo side. Because of the shallow depth, both units are designed for placement directly against a wall or in a corner, and the Duo has a built-in wall bracket for mounting. Floor placement on the supplied rubber feet is also listed by the maker. Buying the Duo later is an upgrade path for owners who start with a single Sub Solo, and the long supplied cable gives freedom to put the second unit on the opposite side of the room. Like other System Audio products it is sold with free shipping and a 45-day home trial, and it comes with a 7-year factory warranty once registered.

Pairing

The Sub Solo itself links wirelessly over WiSA HT to a Stereo Hub HT or Surround Hub, so the Duo slots into Silverback systems built around the Legend 5.2, Legend 40.2 and Legend 60.2 Silverback DS speakers or the Silverback 1. The Sub Solo also has a line input for a wired source, while its own standby draw is below 7 W. Sub Solo lists at EUR 1,599, so the complete two-box set costs EUR 2,498 before any hub.

Alternatives

The Signature Sub 8 is a self-powered System Audio subwoofer with two 8 inch Vulcano drivers in a sealed 29.6 x 29.6 x 31 cm cabinet, which works on its own without a Sub Solo.