ESX VX21PRO

The ESX VX21PRO from the VISION VX PRO series is a no-compromise 53 cm (21-inch) SPL subwoofer designed for extreme bass performance and the highest sound pressure levels. With a power handling capacity of 6,000 watts RMS and up to 12,000 watts of peak power, this subwoofer is one of the most powerful models in the ESX lineup.

Its solid cast aluminum basket provides the necessary stability, while the quadruple magnetic drive—with a magnet weight of approximately 17 kilograms—delivers tremendous driving force. The glass-fiber-reinforced paper cone, with an effective cone area of 1,662 cm², combined with the double-stitched High-Roll foam surround, enables exceptionally high air displacement.

An eight-layer 100-mm voice coil with an 80-mm winding height and a six-layer Nomex suspension ensure high power handling and precise cone control. With a linear stroke of ±23 mm and a maximum mechanical excursion of ±35 mm, the VX21PRO is designed for demanding SPL applications.

Technical Specifications

General Characteristics

• Manufacturer: ESX

• Model: VX21PRO

• Series: VISION VX PRO

• Product Type: SPL Subwoofer

• Nominal diameter: 53 cm (21 inches)

• RMS Power Handling: 6,000 watts

• Maximum power rating: 12,000 watts

• Impedance: 2 + 2 ohms (dual voice coil)

• Efficiency (1 W/1 m): 92 dB

• Maximum in-car sound pressure level according to the manufacturer: 160 dB
  
  

Diaphragm and Actuator

• Diaphragm material: Glass-fiber-reinforced paper

• Diaphragm area (Sd): 1,662 cm²

• Edge: Double-stitched High-Roll Foam edge

• Centering spider: 6-layer Nomex spider

• Basket material: Die-cast aluminum

• Magnetic Drive: Quadruple Magnet System

• Magnet weight: approx. 17 kg

• Magnetic strength: 4 × 150 oz

• Magnet dimensions: Ø 250 × 100 mm

• Voice coil diameter: 100 mm (4 inches)

• Voice coil construction: 8-layer

• Voice coil winding height: 80 mm

• Voice coil wire: Copper-clad aluminum flat wire

• Voice coil former: Black anodized aluminum

• Linear diaphragm stroke: ±23 mm

• Maximum mechanical deflection: ±35 mm

• Mass moved (Mms): 486.96 g
  
  

Thiele-Small parameters

• Resonance frequency (Fs): 27.4 Hz

• DC resistance (Re): 1.8 + 1.8 ohms

• Mechanical Quality (Qms): 6.51

• Electrical quality (Qes): 0.64

• Overall Quality (Qts): 0.58

• Equivalent volume (Vas): 265.9 liters

• Voice coil inductance (Le): 1.45 mH

• Force factor (BL): 21.6 N/A
  
  

Dimensions and Connections

• Outer diameter: 545 mm

• Installation diameter: 495 mm

• Installation depth: 335 mm

• Integrated speaker cables: 10 mm²

• Cable length: 1.5 m

• Shipping weight according to the data sheet: 50.4 kg
  
  

Case Recommendations According to ESX

Bass-reflex enclosure

• Net volume: 210 liters

• Bass reflex ports: 2 × 200 mm

• Port area: 650 cm²

• Port length: 65 cm

• Tuning frequency (Fb): 33 Hz

• Lower cutoff frequency (F3): 28 Hz
  
  

Bandpass enclosure

• Chamber volume (closed): 100 liters

• Ventilated chamber volume: 150 liters

• Bass reflex ports: 2 × 200 mm

• Port area: 630 cm²

• Port length: 30 cm

• Tuning frequency (Fb): 50 Hz

• Lower cutoff frequency (F3): 27 Hz