SVS SB17-Ultra Subwoofer Black Oak

The SVS SB17-Ultra Subwoofer represents the pinnacle of SVS's sealed subwoofer engineering, sitting at the top of the company's sealed subwoofer range. Winner of the EISA 2025–2026 Best Subwoofer award, it pairs a custom 17-inch high-excursion driver with a purpose-built dual mono amplifier to deliver bass extension to 15Hz with the speed and transient precision that sealed enclosures are prized for.

Driver & Motor System

The 17-inch front-firing driver uses a glass fibre composite diaphragm for high stiffness and low mass, enabling controlled pistonic movement across the full operating range. A 55 lb toroidal ferrite magnet motor assembly provides the magnetic flux density needed to manage the driver’s long-throw excursion without magnetic saturation. The voice coil is wound with four layers of bifilar copper-clad aluminium on an 8-inch former — the bifilar winding geometry maximises conductor packing within the gap, increasing force generation per unit of input current.

Dual Mono Amplification

The STA-2800D amplifier is built as two independent mono Class D stages, each driving one voice coil of the driver directly. Eight 60A 200V MOSFETs handle current delivery, providing substantial headroom for dynamic transients. Because each voice coil draws current from its own dedicated stage rather than a shared output, the total current demand per stage is halved — reducing the load placed on the household mains circuit while simultaneously doubling the current available to the driver as a whole. The switch-mode power supply runs at high efficiency and generates less heat than a conventional linear supply, contributing to stable long-term operation at high output levels.

DSP & Control

A 295MHz Analog Devices Audio DSP processes all signal paths using double-precision 56-bit filtering, providing the numerical precision needed for aggressive room correction and parametric EQ without accumulating rounding errors. The SVS smartphone app (iOS, Android, Amazon Fire) gives full remote control from the listening position: six factory preset EQs cover common room and use-case scenarios, while manual adjustment of the low-pass filter, phase, polarity, and room gain compensation allows custom tuning. Auto Room Equalisation uses the smartphone’s built-in microphone to measure the in-room response and apply compensating EQ automatically.

Cabinet & Installation

The cabinet is constructed from double-thick MDF panels with internal bracing to minimise cabinet-induced colouration. Iso-elastomer isolation feet are included to decouple the cabinet from the floor and reduce structure-borne transmission. The front-firing driver orientation makes placement less critical than downward- or rear-firing designs — the SB17-Ultra can be positioned close to a wall or in a corner without the driver port interaction that affects ported designs.