MartinLogan Grotto 12 Powered Subwoofer

What You Need to Know

Minimalist Styling, Maximum Performance

The original Grotto set the standard for clean, powerful bass in a compact, decor-friendly design. The all-new Grotto 12 carries that legacy forward with serious muscle: a Triple 12-inch Hybrid Woofer System and a 2,000-watt peak amplifier delivering deep, controlled, impactful bass from an elegantly understated cube. Three full-faced grilles conceal its powerful nature—until the first bass note drops.

The Triple 12" Hybrid Woofer System

A high-excursion 12-inch aluminum-cone active woofer in a rigid cast-aluminum basket is flanked by dual 12-inch aluminum passive radiators—engineered with Klippel analysis to the same standard as the active driver. The layout delivers the best of both worlds: the extended low-frequency output of a ported design with the compact size and tight, articulate bass of a sealed cabinet, reaching down to 22Hz.

Massive Power, Precise Control

MartinLogan's proprietary Magnitude MT-2kW amplifier supplies up to 2,000 watts peak (1,000W RMS) of ultra-efficient, low-distortion Class D power—concussive impact with effortless musicality. The 500MHz Vojtko DSP engine with 64-bit processing governs everything in real time, enabling app control, built-in wireless, and compatibility with the award-winning Anthem Room Correction system.

Wireless Included, Connections for Everything

A wireless receiver and transmitter come in the box—lossless, low-latency, with forward error correction. Wired options cover XLR LFE, stereo/LFE RCA, and speaker-level inputs (so the sub receives the same sonic signature as your amplifier), plus an RCA sub output for chaining multiple subs. Integrated anti-vibration feet (carpet spikes included) keep the bass tight and the neighbors happy. Finished in Gloss Black.

Features & Specifications

Triple 12" Hybrid Woofer System

Active aluminum woofer plus dual passive radiators—ported extension, sealed-box control.

Magnitude MT-2kW Amplifier

2,000W peak / 1,000W RMS of clean, low-distortion Class D power.

Vojtko DSP Engine

500MHz, 64-bit processing controls performance in real time with audible transparency.

Wireless Receiver and Transmitter Included

Lossless, low-latency wireless connection right out of the box.

App Control + Anthem Room Correction

Tune from your seat; calibrate to your room in minutes with ARC (mic kit sold separately).

Anti-Vibration Feet

Reduce floor and wall vibrations for cleaner bass; carpet spikes included.

Specifications

•       Type: Sealed Powered Subwoofer with Hybrid Woofer System

•       Frequency Response: 22 - 120Hz ± 3dB (Anechoic via LFE input)

•       Woofer System: Triple 12" Hybrid — 1 High-Excursion Aluminum Cone (Cast Aluminum Basket) + 2 Passive Radiators

•       Amplifier: Magnitude MT-2kW — 2,000W Peak / 1,000W RMS

•       DSP: 500MHz Vojtko Engine, 64-Bit Processing

•       Wireless: Integrated Receiver; Wireless Transmitter Included

•       Inputs: RCA (L/R/LFE), XLR (LFE), Speaker Level (L/R); Simultaneous Connections Supported

•       Outputs: RCA Sub Out for Multi-Sub Chaining

•       Controls: Backplate Knob + App (Level, Low-Pass Filter, Phase, Movie/Music/Night Presets, 20-30Hz Level, ARC)

•       Cabinet: Sealed 1"-Thick MDF, Reinforced Baffles, Center Brace

•       Feet: Integrated Anti-Vibration (carpet spikes included)

•       Dimensions: 17.8"H x 17.9"W x 17.9"D

•       Weight: 82.5 lbs

•       Finish: Gloss Black

•       Sold By: Each

Frequently Asked Questions

Is the wireless connection really included?

Yes—both the receiver (built in) and the transmitter come in the box, with lossless, low-latency transmission and forward error correction. No wireless kit to buy separately. The subwoofer still needs AC power at its location.

How does the Grotto 12 compare to the Abyss Series?

Same Vojtko DSP, app control, wireless, and ARC compatibility—but the Grotto 12 steps up to larger 12" drivers and double the power of the Abyss 10 (2,000W vs. 1,600W peak) for bigger rooms and deeper, more effortless output. Need even more? Ask us about the Grotto 15.

What do I need for Anthem Room Correction?

An ARC Calibration Kit and a PC or Mac (sold separately). Calibration takes just minutes with ARC Genesis software and dials the bass precisely to your room.

Will it work with my non-MartinLogan speakers?

Absolutely. With RCA, XLR, speaker-level, and wireless connections, the Grotto 12 integrates with nearly any system—the speaker-level inputs even let it inherit the sonic signature of your chosen amplifier.

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