Hertz Mille MP 250 D4.3 - 25cm subwoofer

Hertz Mille MP 250 D4.3 PRO

Outstanding performance in a compact size - that is the aim of the Mille PRO car audio subwoofers.
The strength of the Research and Development Department is its know-how gained from the development of Mille Legend.
The R&D team has optimized the manufacturing process to make the "Hertz Sound experience" accessible to a wider audience by partially adopting the technologies and materials of the flagship product of the line.
The speaker cone of the MP 250 D2.3 is made using the same construction process used for Legend: wood pulp is pressed with the addition of mineral powders. The V-cone® profile ensures greater hardness, allowing the speaker cone to act as a piston.
The material that covers them is made of high-purity IIR butyl rubber. The Mille PRO subwoofer is manufactured using Boundary Free Surround technology, like the Legend ML 2000.3 and Legend ML 2500.3, which allows a larger emission surface with the same diameter, so that higher sound pressure can be generated.
The compact, non-resonant 6-spoke aluminum alloy basket, identical to that of the top-of-the-range ML 2500.3, contributes to the mechanical damping of the subwoofer while being completely sound-permeable.
The 4-layer 65 mm voice coil is more than 60 mm high and wound in a TIL-P bending bracket, which ensures high linear displacement.
The configuration of an impedance of 2 ? + 2 ? through DVC (dual voice coil) makes the subwoofer flexible enough to keep up with any amplifier system. The air cooling and pressure relief system makes it possible to dispense with a central hole in the base plate.
This brings three advantages: – Better thermal inertia, which leads to lower operating temperatures during musical transients; – The magnetic field induced in the coil is maximized – with the same overall dimensions of the motor.
A larger amount of iron in the pole uses the maximum flux density generated by the magnet, thus reducing the likelihood of saturation magnetization; – With the option of installing the subwoofer directly on the wall of the box, the minimal dimensions are fully exploited.
The damping rubber disc included in the delivery can be used to attach the subwoofer to the box. This allows air to be exchanged for the 10 ventilation holes in the base.
The holes behind the voice coil winding and the 10 ventilation holes in the base plate ensure greater air exchange to the inner layers of the coil and harmonize with the innovative mounting system. The air is directed through the opening to keep the operating temperature of the coil low - even with extreme music programs.
The connection has stable plug connections with a cover to prevent short circuits. The ability to use up to 8 AWG cables ensures extremely low wiring resistance in low impedance (1 ohm) configurations. 

Technical specifications

• Size mm: 250 (10)
• Power handling - Peak W: 1200
• Power handling - Continuous W: 600
• Impedance: 4 + 4 ohms
• Sensitivity dB SPL: 83.5
• Voice coil diameter: mm (inch) 65 (2.5)
• Xmax mm: 17.00
• X-Mech mm (inch): ± 27 (1.06)
• Re: 1.8 Ohm
• Fs Hz: 27.00
• Vas l: 31
• Number: 0.5
• Qes: 0.53
• Sqms: 5.8
• Spl dB: 83.5