Sonance SWT

Sonance SWT, wireless subwoofer transmitter

A subwoofer rarely performs at its best where the cable happens to reach. This small Sonance unit connects to the amplifier’s subwoofer output and sends the signal wirelessly up to 9 metres to the brand’s Impact and D8 subwoofers, which already have a built-in receiver. The subwoofer then needs only a mains socket and can be placed wherever it sounds right.

Position the subwoofer without running a cable

In a room, bass depends heavily on the subwoofer’s position: the same model can sound hollow in one corner and become full and even two metres away. The right spot is often far from the TV cabinet, and that is where the cable becomes a problem, with a room to cross, a skirting board to follow and a rug to lift. The SWT eliminates this cable. It fits in the palm of your hand (80 × 32 × 69 mm and 160 g), its black plastic housing slips into the cabinet beside the amplifier, and it requires only a 5 V power supply via its DC input. On the back are two line-level RCA inputs and a pairing button, while a blue indicator on the front shows the connection status. The 9-metre range applies under optimal conditions, with no obstructions: a partition wall, metal furniture or an enclosed cabinet will reduce it, but it easily covers a typical living room.

A tri-band connection with an uncompressed signal

The SWT transmits over three frequency bands, 2.4 GHz, 5.2 GHz and 5.8 GHz. This spread makes the connection highly resistant to interference from Bluetooth devices, dual-band Wi-Fi routers and microwave ovens, which crowd the same airwaves in most homes. The signal travels uncompressed, at 24-bit and up to 192 kHz: the subwoofer receives exactly what the amplifier sends it, without the data reduction imposed by Bluetooth. Latency, meaning the delay in sound between the amplifier and the subwoofer, remains below 20 milliseconds. This delay is small, and a home cinema amplifier easily compensates for it using the subwoofer distance setting, keeping the bass aligned with the main speakers and the picture.

Connection and pairing in two presses

With a home cinema amplifier, a single RCA cable is enough, between the subwoofer output (often labelled Sub or LFE, for the low-frequency effects channel) and the transmitter’s Left/LFE input. With a preamplifier or stereo amplifier without a subwoofer output, the left and right line outputs connect to the Left/LFE and Right inputs. On the subwoofer, the input selector must be set to Wireless: without this setting, no sound comes through. Pairing is performed once, with both devices powered on. Hold the transmitter’s PAIR button until its indicator flashes blue, release it, then, within 30 seconds, hold the subwoofer’s Wireless Sync button until the transmitter’s indicator turns solid blue. The two devices are then paired and reconnect whenever they are switched on.

Sonance subwoofers compatible with the SWT

The SWT works with subwoofers that have a built-in Sonance wireless receiver: the Impact i8, i10 and i12 (20, 25 and 30 cm drivers) and the D8, in black or white. The Impact models combine a high-excursion front-firing driver, a Laminar Flow port that limits chuffing noise and a piano black finish beneath a fabric grille. All these subwoofers retain their wired line-level and speaker-level inputs, leaving the option to go wireless later or return to a cable if the setup changes. They can also be calibrated using Sonance’s SonARC app, which measures the room and adjusts the subwoofer’s response, with a 16-band equaliser on the Impact models.

Technical Specifications

Range

• Up to 9 m (under optimal conditions)

Compatibility

• IMPACT subwoofers and D8