【ESB 4000 SERIES Rear Separate 2-Way｜Car Audio Speakers Balancing Power and Finesse】

This is the ESB 4000 SERIES Rear Separate 2-Way, designed for those who don’t just want rear speakers to play sound, but want the overall thickness and sense of spaciousness of the music to be properly shaped as well.

For the 16cm mid-bass, it uses a paper cone made from long-fiber pulp with special treatment. With a balanced combination of lightness and rigidity, along with appropriate internal damping, you can aim for a presentation that delivers both power and delicacy—from the midrange that forms the foundation for vocals to the mid-lower frequencies that support the music’s overall body.

It’s also built for long-term, stable use, featuring a large-diameter voice coil that supports high-output playback, a vent structure designed with heat dissipation in mind, and an aluminum die-cast frame. If you’re concerned that when you turn the volume up the sound becomes thin or the low end gets blurry, this mid-bass is one you should seriously consider.

The tweeter is a 28mm soft-dome type. Thanks to the silk dome with polymer laminate and the N-52 neodymium magnet, the design focuses on the expression of fine sonic details and the extension of the high frequencies. While adding airiness and the outlines of the vocals—qualities that are difficult to reproduce with the mid-bass alone—it naturally supports the music from the rear.

Speakers Where Sound Cohesion Changes with Installation

Speakers aren’t determined by unit performance alone. Depending on the vehicle-specific mounting space, the condition of the door and trim, the mounting baffle/foundation, wiring, and the balance between the front and rear speakers, the final result will differ even with the same product.

Especially when combining a separate 2-way setup in the rear, it’s important to adjust while checking how the volume and tonal character connect with the front. Rather than making only the rear stand out, think about the direction that will let music spread naturally throughout the entire cabin—based on the vehicle model and how you listen.

If you’re considering the ESB 4000 SERIES, please tell me about your current system and the sound direction you want. I wouldn’t decide just by swapping the speakers themselves; I’ll help you consider a configuration that makes sense together—after confirming the installation approach and how it matches with your existing system.

Main Specifications

[Basic Information]
Product name: ESB 4000 SERIES Rear Separate 2-Way
Type: Separate 2-Way speaker

[16cm Mid-Bass]
Unit: 165mm paper cone
Diaphragm: Special treatment / long-fiber pulp
Frequency response: 50Hz–6.0kHz
Sensitivity: 89.5dB
Impedance: 4Ω
Maximum input: 300W
Minimum resonant frequency (Fs): 57.3Hz
Magnet: Y35 ferrite
Voice coil: Copper-coated aluminum
Frame: Aluminum die-cast
Edge: Nitrile rubber
Baffle cutout dimension: 143mm
Outer frame diameter: 165mm (main unit) / 170mm (with grille installed)
Mounting depth: 67mm
Terminals: Both plus and minus terminals use 250 faston

[28mm Tweeter]
Type: Soft-dome tweeter
Diaphragm: Silk dome with polymer laminate (Sonatex™)
Magnet: N-52 neodymium
Voice coil: Vented voice coil, copper-coated aluminum
Included mounts: CNC-machined aluminum flush mount / resin flush mount / adapter mount / surface mount

• Since installation methods and required modifications vary by vehicle model, when considering installation we will guide you after confirming the actual vehicle and your current audio setup.
• The dedicated grille & ring are sold separately.

Shop owner: Komizo (小溝)