Sonus faber Gravis I - Black - White - Walnut - Wenge

Description

The Compact Subwoofer of the Gravis Collection

The Gravis I is the entry point in the Sonus faber active subwoofer lineup. Its proposition is clear: offer a true musical subwoofer in a compact format (33.4 cm tall, 14 kg), with the house's Italian finish, designed to complete a stereo system built around bookshelf speakers (Lumina I/II, Sonetto I/II G2) or to serve as the .1 channel in a home cinema. Hand-built in the Sonus faber workshops in Vicenza, Italy.

8" Ultra Long Throw Driver, Sealed Box Enclosure

The Gravis I uses an 8" (210 mm) driver specifically designed for long excursion, with a treated paper cone and a wide rubber surround. It is loaded in a sealed box (closed loading), with no bass-reflex port — a deliberate choice. The sealed box produces tight, fast, precise bass, better suited to musical reproduction, where a ported subwoofer gains extension at the cost of time-domain precision. The driver fires downward, a configuration that distributes bass evenly across the room and makes placement less critical.

150 W RMS Class AB High-Linearity Amplifier

The amplification is a high-linearity Class AB module, rated 150 W RMS with 250 W peak. The choice of Class AB (as opposed to the Class D typical of budget subwoofers) delivers a more musical signature and better transient fidelity — consistent with the Gravis I's musical vocation. 

Two Inputs with Independent Volume Controls: The Key Feature

The Gravis I features two distinct inputs each with its own volume control: (1) the LFE input (RCA) receives the .1 channel from a home cinema receiver or processor; (2) the High-Level input uses a Neutrik Speakon® 4-pole connector (professional quality) plugged in parallel to the speaker outputs of the stereo amplifier. This dual input with separate volumes solves a real problem: in a hybrid music + cinema system, each source demands a different subwoofer level. Here, you calibrate once for music, once for cinema, and switch between modes without touching anything.

Adjustable Crossover 30–120 Hz, 24 dB/Octave Slope

The integrated low-pass filter is continuously adjustable from 30 to 120 Hz, with a 24 dB/octave slope — a steep slope that cleanly cuts the top of the subwoofer's spectrum to avoid any audible overlap with the main speakers. A phase inversion switch (0/180°) also allows compensation for acoustic delays related to placement. The subwoofer's auto on/off detects the presence of an audio signal; it can be disabled if the user prefers manual control.

Compact Format with Three Italian Finishes

The compact cabinet (33.4 × 28.6 × 31.6 cm, 14 kg) fits where a traditional subwoofer would be too bulky: under a desk, next to an armchair, in a corner of a compact living room. The wood veneer is offered in three finishes: open pore, matte, or high-gloss. Black leather top panel. Rubber pad decoupling included. 

Frequently Asked Questions

Why choose the Sonus faber Gravis I?

The Gravis I is the most compact active subwoofer in the Gravis collection (33.4 cm tall, 14 kg), designed for musical listening and home cinema in small to medium-sized rooms. Its sealed-box loading, 150 W RMS Class AB amplifier, and two inputs with independent volume controls (LFE + High-Level Speakon) make it both musical and flexible — it complements a pair of Lumina II in stereo as well as a multichannel system.

Why a sealed box rather than a bass-reflex ported subwoofer?

Sealed-box loading and ported bass-reflex target two different trade-offs. Bass-reflex gains extension and efficiency at the lowest frequencies but introduces a slight time delay and a rounder signature. Sealed-box produces tighter, faster, more precise bass, better time-aligned with the rest of the audio signal — a choice better suited to musical reproduction, which Sonus faber prioritized for the Gravis I.

What is the High-Level Speakon input for?

The High-Level input (via Neutrik Speakon® 4-pole connector) is wired in parallel with the speaker outputs of your stereo integrated amplifier. This connection allows the subwoofer to receive the same amplified signal as the main speakers, providing a more coherent musical integration than a simple pre-amp output. Combined with the independent LFE output for cinema, the Gravis I can serve both uses without compromise, with separate volume settings.

Which speakers does it pair best with?

The Gravis I is particularly well suited to bookshelf loudspeakers and compact floorstanders: Lumina I, II, or III from the same collection, Sonetto I or II G2, or any other 2-way speaker that benefits from bass reinforcement in the lowest frequencies. For larger rooms or 3-way floorstanders (Sonetto V/VIII G2, Homage), the larger subwoofers in the same collection are more appropriate.

How do I set the crossover?

The setting depends on the bass extension of your main speakers. Rule of thumb: set the Gravis I's crossover about 10 Hz above the lower limit of your fronts (at -3 dB). For a home cinema, generally let the receiver or processor manage the crossover (typically 80 Hz) and set the Gravis I to the maximum (120 Hz). Don't forget the phase switch: try both positions and keep the one that gives the most bass reinforcement at the listening position.

What's in the Box

Sonus faber Gravis I Active Subwoofer

Power cable

Rubber decoupling pads

Owner's manual