Product Description
The original Martin Logan Grotto subwoofer set a standard for clean, powerful bass in a compact, décor-friendly design. The all-new Grotto Series carries on that legacy with advanced amplification, precision drivers, and ARC Genesis Room Correction; delivering deep, controlled, and impactful bass from an elegantly understated form. With larger drivers and more power than its smaller siblings, the Abyss 8 and 10, the Grotto 12’s Hybrid Woofer System uses dual 12-inch passive radiators to enhance the low frequency output of its powerful, active 12-inch aluminium cone woofer. This high-output woofer system is driven by robust amplification and a best-in-class 64-bit DSP Engine to extract maximum performance. Grotto 12 offers a wide range of connectivity options including XLR, RCA, Speaker Level, and built-in wireless (included - not optional like most!), plus the added convenience of the MartinLogan Subwoofer Control App. With support for the award-winning Anthem Room Correction (ARC) system, your Grotto 12 can also be expertly tuned in a matter of minutes using the optional ARC Calibration Kit.
Bold Performance, Subtle Styling
The deceptively powerful Grotto 12 can blend into virtually any environment without overwhelming the aesthetic design of the room. However, once the first bass note drops, the audience can easily sense its full potential. The three full-faced grilles conceal the powerful nature of Grotto 12, making it an ideal choice for those looking for authoritative bass in a subtle package.
12" Hybrid Woofer System
Utilising state-of-the-art Klippel analysis, all Grotto Series drivers are specifically engineered for dynamic output with low distortion. The Grotto 12 pairs dual 12-inch passive radiators with a matching 12-inch active woofer. This driver layout delivers the best of both worlds; the increased low frequency extension of a ported design and the more compact sizing and tighter bass attributed to sealed designs. All of the woofer cones are made from aluminium to ensure quick response, high output, and solid reliability. Aluminium is an ideal material for such an application, due to its excellent heat dissipation and high strength to weight ratio. Grotto Series subwoofers also feature rigid cast aluminium baskets and large motor structures to best handle the colossal power of the MT-2kW amplifier. While these drivers do not receive direct power, engineering the passives to the same standard as the active driver ensures they match both acoustically and aesthetically.
Specifications
|
Digital Signal Processing |
Ultra High-Resolution 500MHz Vojtko DSP Engine with 64bit processing |
|
Frequency Response |
22-120 Hz ±3 dB (Anechoic via LFE input) |
|
Low Frequency Transducer |
Triple 12" (30.5cm) |
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Cabinet |
Sealed 1" thick MDF cabinet with centre brace and reinforced baffles |
|
Amplifier |
MartinLogan Magnitude MT2kW Amplifier: 2000W peak (1000W continuous) |
|
Controls (Backplate) |
Level: Interactive LED Backlit Knob, Min-Max |
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Controls (via Bluetooth) |
Level: -40 to 12dB (Min-Max) |
|
Wireless Inputs |
Integrated Wireless Receiver, Wireless Transmitter Included |
|
Inputs |
Line Level: Left, Right, and LFEXLR: LFE |
|
Outputs |
RCA Sub Out (combines and repeats all incoming signals to an additional subwoofer) |
|
Power Draw |
Max: 1000W |
|
Feet |
Integrated Anti-Vibration Feet (carpet spikes included) |
|
Weight |
37.4 kg |
|
Dimensions (H x W x D) |
45.2cm x 45.4cm x 45.4cm |
|
Finish |
Gloss Black |

Raw Power Meets High Precision With
The Magnitude MT-2kW Amplifier
MartinLogan’s proprietary Magnitude Amplifiers unleash the full potential of the custom engineered Grotto woofers. The highly advanced Magnitude MT-2kW delivers up to 2,000w Peak (1,000w RMS) of low-distortion power for concussive impact and effortless musicality. This ultra-efficient Class-D amplifier delivers nearly endless reserves of clean power with incredible precision and control, even during the most demanding content.
Advanced Vojtko DSP Engine
Grotto subwoofers utilise the cutting edge, ultra-high resolution Vojtko DSP engine, named after MartinLogan’s Chief Audio Technologist, Joe Vojtko. Featuring a best-in-class 500MHz DSP with 64-bit processing, the Vojtko DSP engine controls all aspects of subwoofer performance in real time. This level of computing power enables advanced features like wireless app control, integrated wireless signal connection, and other advanced DSP functions with complete audible transparency, enabling MartinLogan engineers to calibrate the subwoofer for maximum output and fidelity. This sophisticated DSP engine enables compatibility with the award-winning Anthem Room Correction system.


Optimize Bass Performance with the
Award-Winning ARC® Genesis Room
Correction System
This highly advanced software measures the in-room performance of the subwoofer and conducts custom equalisation, tuning, and calibration to achieve the highest levels of bass impact, smoothness, and accuracy. Calibration only takes a few minutes using the ARC Genesis software, and an ARC Calibration Kit(sold separately) which works on both PC and Mac.
Structurally Sound
The cabinet plays a critical role in the sound quality of a speaker. Grotto 12 cabinets are made of one-inch thick MDF (Medium Density Fibreboard) with additional reinforcement on the woofer baffles and a large central brace, robust enough to withstand the forces of the 12-inch Hybrid Woofer System. This solid construction also provides a more stable platform for the woofer system, resulting in cleaner, more articulate bass.


Reduced Vibration, Enhanced Bass
Solid bass performance is a critical component of any audio system, and helps provide visceral impact to music and film soundtracks. Grotto subwoofers feature integrated anti-vibration feet to improve bass performance by reducing floor and wall vibrations. Drastically reducing the energy transfer between the subwoofer and the floor, unwanted room rattles and buzzes are removed, leaving tighter, cleaner bass and improved system clarity and dynamics. As a less intrusive alternative to acoustic room treatments, the integrated anti-vibration feet can also aid in minimizing noise complaints by reducing vibration transfer into adjoining rooms. These feet are safe for all flooring types and the optional carpet spikes are included to further improve performance on carpeted floors.

Robust Connectivity
Grotto subwoofers feature an array of wired installation options in addition to the convenience of the included wireless option. For the best connection, XLR is available for the LFE input. Both Stereo left/right and LFE input are available via RCA, and an RCA Sub Output is available to make it easier to chain multiple subs together, if needed. Grotto Subwoofers also feature speaker level inputs via banana plugs, which some enthusiasts prefer so the subwoofer is driven by the exact same signal being fed to the speakers, in essence receiving the sonic signature of the chosen amplifier. This also makes Grotto subwoofers compatible with nearly any setup, including balanced amplifiers. Although rare, as with all MartinLogan subwoofers, the available inputs can be used simultaneously if desired. The pristine processing and filtering made possible by the advanced Vojtko DSP engine enables Grotto subwoofers to offer the highest levels of input purity, regardless of the connection method. With a variety of input options to choose from, Grotto subwoofers can add superior bass reinforcement to nearly any system.
Built-In Wireless Capability
While a hard-wired connection is still the best method, for flexible placement options, Grotto subwoofers come with a built-in Wireless Receiver and Wireless Transmitter. Featuring lossless transmission, forward error correction, and low latency, even the most discerning enthusiast will be thrilled with the results.


Ultimate Tuning & Control
MartinLogan’s Subwoofer Control app for iOS and Android devices offers the most personalised and convenient way to adjust a subwoofer. This allows the user to easily adjust settings such as Volume, DSP Mode, Phase, and other features providing the most intuitive control and ease of use. The Control App is also an invaluable tuning aid, enabling the user to hear the effects of setting changes from the listening position in real time.