DS18 8" 400 Watt RMS Dual 4-Ohm Water Resistant Marine Audio Subwoofer PSW8.4D

• SHALLOW-MOUNT POWER BEAST: 8″ subwoofer delivers 400W RMS / 800W MAX with a compact 3.5″ mounting depth, perfect for under-seat boxes and tight enclosures that still demand real bass.
• DUAL 4-OHM VOICE COILS = FLEXIBLE WIRING: Dual 4-ohm configuration lets you wire series or parallel for easy amplifier matching, cleaner power delivery, and better system tuning.
• BUILT FOR HEAT, BUILT TO LAST: Features a 2″ aluminum voice coil, ferrite motor, and water-resistant paper cone with aluminum reinforcement for improved cooling and long-term durability.
• DEEP, CONTROLLED LOW-END RESPONSE: Plays down to 20 Hz with a sensitivity of 81 dB, delivering tight, accurate bass that hits hard without overpowering the rest of your system.
• PERFECT FOR COMPACT & MARINE BUILDS: Designed for sealed enclosures from 0.35–1.3 cu ft, making it ideal for trucks, boats, powersports, and space-limited installs.

DS18 8" 400 Watt RMS Dual 4-Ohm Water Resistant Marine Audio Subwoofer PSW8.4D

This Listing Includes

• (1) DS18 8" Marine Subwoofer PSW8.4D

The DS18 PSW8.4D is a shallow-mount 8†dual voice coil subwoofer built to deliver serious low-end impact where space is limited. Rated at 400W RMS / 800W MAX, this sub is engineered for tight installs without sacrificing bass authority.

Tight Spaces, Deep Bass. With a 3.5†mounting depth and a total depth of only 4â€, the PSW8.4D fits cleanly into under-seat enclosures, compact truck boxes, and space-restricted builds, while reaching frequencies as low as 20Hz =  Big bass, small footprint.

Dual 4-Ohm Voice Coils = Wiring Flexibility. The dual 4-ohm voice coil design allows series or parallel wiring, giving you more options to match your amplifier and fine-tune your system. That flexibility means cleaner power delivery and more reliable performance at higher output levels.

Built to Hit Hard and Stay Cool: A 2†aluminum voice coil paired with a water-resistant paper cone reinforced with aluminum improves heat dissipation and durability. The ferrite motor, high-roll rubber surround, and solid suspension components are designed for long play sessions at elevated volume without losing control.

Balanced, Accurate Bass.

With an 81dB sensitivity rating and an optimal sealed enclosure volume of 0.35–1.3 ft, the PSW8.4D delivers tight, controlled bass that blends smoothly into your system while still hitting hard when called on. Bring powerful low-end performance to tight mounting spaces with the DS18 PSW8.4D.

Features

• Shallow-mount 8†marine subwoofer for tight installations


• 400W RMS / 800W MAX power handling


• Dual 4-ohm voice coils for flexible wiring configurations


• Water-resistant paper cone with aluminum reinforcement


• Compact 3.5†mounting depth ideal for small enclosures


• Designed for marine, powersports, and off-road use

Specifications:

General

• Nominal Diameter: 8 in / 203 mm


• Nominal Impedance: Dual 4 Ohm


• RMS Power Handling: 400 Watts


• MAX Power Handling: 800 Watts


• Sensitivity (1W/1M): 81 dB


• Frequency Response: 20 Hz – 300 Hz


• Recommended Low-Pass Crossover: 100 Hz

Motor

• Voice Coil Diameter: 2 in / 50.8 mm


• Voice Coil Former Material: Aluminum


• Winding Material: Copper


• Cone Material: Water-resistant paper with aluminum reinforcement


• Surround Material: Rubber


• Magnet Material: Ferrite


• Magnet Weight: 38 oz


• Displacement Volume: 0.5 L / 0.017 cu ft


• Basket Material: Steel


• Basket Finish: Matte Black

Thiele & Small Parameters

• Equivalent Volume (Vas): 9.38 L / 0.33 cu ft


• Excursion (Xmax, One Way): 8.5 mm


• Free Air Resonance (Fs): 42 Hz


• Mechanical Q (Qms): 4.08


• Electrical Q (Qes): 1.06


• Total Q (Qts): 0.84


• Moving Mass (Mms): 98.43 g


• Compliance (Cms): 141.08 mm/N


• BL Factor: 12.61


• Voice Coil Inductance (Le): 1.83 mH


• Diaphragm Area (Sd): 216 sq cm


• DC Resistance (Re): 3.2 + 3.2 Ohms


• Efficiency Bandwidth Product (EBP): 39.6

Recommended Enclosure

• Sealed Internal Volume Range: 10 – 37 L / 0.35 – 1.3 cu ft


• Sealed Box Output Response (F3): 38 – 43 Hz

Dimensions:

• Overall Diameter: 8.6 in / 220 mm


• Overall Depth: 4 in / 102 mm


• Front Mount Baffle Cutout: 7.5 in / 191 mm


• Mounting Depth: 3.5 in / 90 mm


• Motor Diameter: 5.27 in / 134 mm