• Flat-mount design makes serious bass possible where conventional subwoofers will not fit
  
• Strong motor and 4-layer copper coil give the driver real authority for its depth class
  
• Cast basket construction helps maintain control and stability under load
  
• Sandwich paper cone balances output, control, and usable low-frequency extension
  
• Dual 2 ohm configuration gives flexible amplifier matching for compact high-output builds

• Product type: High-quality flat SPL subwoofer
  
• Model: GZHW 10SPL-D2 FLAT
• Series: Hydrogren Series
  
• Diameter: 25 cm / 10″
  
• Power handling: 600W RMS / 1000W max
  
• Impedance: 2 x 2 ohms
  
• Efficiency: 85 dB
  
• Power recommendation: 400 – 1000W RMS
  
• Motor: Ferrite
  
• Voice coil diameter: 63 mm / 2.5″
  
• Voice coil: 4-layer copper
  
• Cone: Sandwich paper
  
• Dust cap: PP
  
• Surround: Durable U-shape rubber surround
  
• Basket: Solid aluminum cast
  
• Terminals: Push terminal
  
• Re (series): 4.01 ohms
  
• Fs: 35.5 Hz
  
• Qms: 8.937
  
• Qes: 0.456
  
• Qts: 0.434
  
• Vas: 19.7 L / 0.70 cu.ft.
  
• Mms: 189.5 g
  
• Xmax: 29 mm / 1.14″ p2p
  
• BL: 19.3 Tm
  
• Mounting diameter: 238 mm / 9.37″
  
• Mounting depth: 103 mm / 4.06″
  
• Verification: Klippel® optimized

• Vented enclosure: 17L net / 0.60 cu.ft.
  
• Port: 1 x 70 mm / 2.76″
  
• Port length: 300 mm / 11.81″
  
• F3 frequency: 39 Hz
  
• Sealed enclosure (minimum): 15L net / 0.53 cu.ft.
  
• Qtc / F3: 0.67 / 58 Hz
  
• Note: sealed enclosure offers more limited low-frequency extension and reduced power handling

• Space-constrained installs needing genuine subwoofer performance
  
• Under-floor, side panel, and shallow enclosure applications
  
• Compact daily systems using serious mono amplification
  
• Builds where enclosure depth is limited but output still matters
  
• Users wanting a shallow-format sub without stepping into weak, convenience-focused designs

The standout here is the flat-mount design that still has proper motor and coil hardware behind it. A lot of shallow subs make the fitment easy but give away too much performance. This works because it is built to solve the space problem without turning into a compromise piece.