JTR Captivator 4000ULF-LP | Dual 18" 4000W Ultra-Low-Frequency Subwoofer

Freight calculated per order by JTR after sale

The JTR Captivator 4000ULF-LP is a reference-class powered subwoofer engineered for home theaters and high-performance audio systems that demand tremendous output with genuine ultra-low-frequency extension. Combining dual high-excursion 18-inch drivers, a built-in 4000-watt RMS DSP-controlled Class D amplifier and a massive bass-reflex enclosure tuned to 10 Hz, the 4000ULF-LP is designed to reproduce the deepest bass information with exceptional authority.

Rated down to an extraordinary 10.5 Hz ±3 dB, the Captivator 4000ULF-LP reaches well into the infrasonic region, making it particularly suited to reference home cinema where reproducing the full impact of modern low-frequency effects is a priority.

Dual High-Excursion 18-Inch Drivers

The Captivator 4000ULF-LP uses two 18-inch high-excursion drivers with 36 mm of Xmax, providing enormous displacement capability for extremely high output at very low frequencies.

JTR's current driver design incorporates a revised motor structure with more than a pound of aluminum within each driver's motor and less than 1 mH of inductance. JTR states that these drivers deliver approximately 30% lower distortion than its previous reference drivers.

Both drivers are completely front-firing, helping make this exceptionally large subwoofer more flexible when integrating it into a dedicated theater.

4000-Watt RMS DSP Amplifier

Power comes from an integrated 4000-watt RMS Class D amplifier operating at up to 95% efficiency.

Rather than using a generic plate amplifier, JTR incorporates DSP optimized specifically for the drivers and enclosure. The current DSP platform includes automatic input selection, advanced automatic turn-on and a reduced noise floor.

Connectivity includes both balanced XLR and unbalanced RCA inputs, along with a 12-volt trigger for integration with surround processors and home automation systems.

Bass-Reflex Enclosure Tuned to 10 Hz

The 4000ULF-LP is engineered specifically for extreme low-frequency reproduction.

Its enormous bass-reflex enclosure is tuned to 10 Hz and incorporates a large slot port designed to minimize turbulence and compression during demanding high-output passages.

The result is a manufacturer-rated frequency response of:

10.5 Hz – 125 Hz ±3 dB

That places the 4000ULF-LP well beyond conventional subwoofer territory, allowing it to reproduce low-frequency information that can be physically experienced as well as heard.

Low-Profile 4000ULF Configuration

The LP—or Low Profile—configuration packages the dual-driver Captivator platform into a cabinet measuring:

41" H × 39.5" W × 20.5" D

This creates an alternative form factor for installations where the proportions of JTR's other dual-18 Captivator cabinets may not work as well.

For custom home theaters, this additional cabinet configuration gives system designers more flexibility when positioning extremely high-output subwoofers around screen walls, equipment structures and other architectural constraints.

LF Adjust for System Integration

The Captivator 4000ULF-LP includes JTR's LF Adjust, providing additional flexibility when integrating the subwoofer into different acoustic environments.

Low-frequency behavior can vary dramatically between a small enclosed theater, a large open room and an outdoor environment. LF Adjust provides an additional tool for tailoring the Captivator's response to its installation.

When combined with proper placement, DSP and professional calibration, the 4000ULF-LP can become the foundation of an exceptionally capable single- or multi-subwoofer system.

Baltic Birch Construction

Producing substantial output at frequencies approaching 10 Hz places tremendous mechanical demands on a subwoofer enclosure.

JTR constructs the Captivator 4000ULF-LP from 18 mm, 13-ply void-free Baltic Birch plywood, with extensive internal bracing to maintain cabinet rigidity as its dual 18-inch drivers operate at high excursion.

The cabinet is finished in Matte Black Paint and includes a magnetically attached grille.

Ambidextrous Amplifier Placement

The 4000ULF-LP also features JTR's ambidextrous amplifier configuration, allowing the amplifier to be positioned on either the left or right side.

For a subwoofer of this size, that seemingly small detail can be extremely useful when planning access to connections and controls within a dedicated theater or custom installation.

Built for Reference Home Cinema

The Captivator 4000ULF-LP isn't designed simply to add more bass to a conventional system. Its combination of dual 18-inch drivers, 36 mm Xmax, 4000 watts RMS, 10 Hz enclosure tuning and 10.5 Hz rated extension puts it firmly in the category of purpose-built reference cinema subwoofers.

For larger theaters, multiple Captivators can also be incorporated into a professionally designed bass system to increase available headroom while improving low-frequency consistency across multiple seating positions.

Technical Specifications

Shipping / Freight Notice

JTR Speakers products require additional freight charges. Freight is not included at checkout. After your order is received, JTR will calculate the applicable shipping/freight cost based on the product and delivery destination. An additional freight charge will be invoiced after order entry.

JTR Captivator 4000ULF-LP at The Grid HiFi

The JTR Captivator 4000ULF-LP is built for home theaters where true infrasonic extension, enormous dynamic capability and exceptionally high output are part of the design brief. Its dual 18-inch drivers, 4000-watt RMS amplifier and 10 Hz bass-reflex tuning make it a formidable low-frequency foundation for serious private cinema.

At The Grid HiFi in Houston, Texas, we can help design and integrate JTR subwoofers into complete high-performance theater systems, including single- and multi-subwoofer layouts, surround processing, acoustic treatment, system integration and professional calibration.