K-Array Thunder KS3P I – Passive 21-Inch Subwoofer (Black)

Product Overview

The K-Array Thunder KS3P I is a passive 21-inch subwoofer engineered for commercial AV installations that demand deep low-frequency extension from a single compact cabinet. As a high SPL installation subwoofer delivering 139 dB with response down to 30 Hz, it anchors line array and column array systems in auditoriums, houses of worship, and large multi-purpose rooms. Its 4-ohm passive design with 2800 W peak power handling lets integrators centralize amplification in the equipment rack for simpler service access and cleaner commercial deployment. This listing is the black finish; a white KS3PW I version is also available.

Product Description

The KS3P I is built around a single long-excursion 21-inch neodymium magnet woofer with a 4-inch voice coil, producing response from 30 Hz to a crossover-dependent 150/300 Hz upper limit. The neodymium motor keeps the cabinet at 49.2 kg (108.5 lb) — light for a 21-inch enclosure — which eases positioning and rigging during installation. The birch plywood enclosure carries a polyurea coating that resists scuffs, impacts, and environmental wear in both fixed installation and portable production duty. Two SpeakON NL4 connectors accept signal from external amplifiers over 2-wire or 4-wire cable and pass signal through to additional loudspeakers, so multi-cabinet subwoofer arrays wire cleanly without separate distribution hardware. K-Array Kommander amplifiers are the natural drive platform: their DSP presets manage the low-pass crossover at 150 Hz for accurate integration with K-Array column elements such as Kayman and Python. For systems needing even more output, the KS3P I sits between the single-18 Thunder KS2P I and the dual-18 Thunder KS4P I in the passive Thunder lineup.

Key Features

• 21-Inch Neodymium Woofer — A long-excursion 21" driver with 4" voice coil reaches down to 30 Hz for full-bandwidth low-frequency reinforcement in large commercial spaces.
• 139 dB Maximum SPL — High output from a single cabinet keeps bass impact consistent across auditoriums and high-energy program material.
• 2800 W Peak Power Handling at 4 Ohms — The 4-ohm passive design accepts high-output professional amplification and suits centralized amp-rack system architectures.
• Dual SpeakON NL4 Connectivity — Two NL4 connectors accept 2-wire or 4-wire input and route signal through to other loudspeakers, simplifying daisy-chained installations.
• DSP-Managed Crossover — With matched K-Array processing, a preset-dependent low-pass at 150 Hz integrates the subwoofer accurately with Kayman, Python, and other column elements.
• Ultra-Light for a 21-Inch Cabinet — Neodymium magnetics hold weight to 49.2 kg (108.5 lb), reducing labor and structural demands during commercial deployment.
• Polyurea-Coated Birch Plywood Enclosure — The coated plywood cabinet withstands years of installed or portable service without cosmetic or structural degradation.
• Black, White, or Custom RAL Finishes — Factory finish options let the cabinet match architectural requirements in design-sensitive venues.

Typical Applications

• Auditoriums requiring deep low-frequency extension beneath line array or column systems
• Houses of worship reproducing full-range contemporary worship music
• Multi-purpose rooms hosting both speech reinforcement and high-energy events
• All-hands rooms and large commercial meeting spaces with live music or video playback
• Broadcast studios needing controlled, extended low-frequency reinforcement

Technical Specifications

Frequently Asked Questions

Which amplifier should drive the Thunder KS3P I?

The KS3P I is passive and requires external amplification capable of high output into a 4-ohm load with 2800 W peak handling. K-Array Kommander amplifiers are the recommended match because their DSP presets manage the low-pass crossover, but any professional amplifier with adequate power and processing can drive it.

How does it connect within a larger system?

Two SpeakON NL4 connectors accept amplifier signal over 2-wire or 4-wire cable and allow signal pass-through to additional loudspeakers, so multi-cabinet configurations wire cleanly without extra distribution hardware.

Which K-Array speakers pair with the KS3P I?

It is typically deployed beneath K-Array column and line array elements such as Kayman and Python, with Kommander DSP presets aligning crossover and time settings. Browse matching elements in the K-Array collection.

Is the KS3P I suitable for fixed installation?

Yes. The polyurea-coated birch plywood enclosure and available custom RAL finishes are designed for permanent commercial installations as well as portable production work.

Does it integrate with AV control systems?

When driven by K-Array Kommander electronics, the system gains control integration with Q-SYS, Crestron, Control4, and other commercial control platforms, plus Dante networking on supported amplifier models.

What warranty applies?

K-Array products carry a 5-year manufacturer warranty, supported by Creation Networks as an authorized dealer with pre- and post-sale system design assistance.