Hertz, Mille Pro MP250 D4.3

Outstanding performance in a compact size, this is the target of Mille Pro car audio subwoofers. On the strength of its know-how acquired with Mille Legend, the R&D team has optimized the production process to offer the “Hertz Sound Experience” to a wider audience using part of the technologies and materials of the flagship line.  The MP 250 D4.3 cone is made by pressing paper pulp with the injection of mineral powders, the same construction technique used for Legend. The V-cone® profile increases rigidity, allowing the cone to function like a piston. Surround materials consist of high-purity IIR-butyl rubber. Like the Legend ML2000.3 and ML2500.3, the Mille PRO subwoofers are built with Boundary Free Surround technology allowing for a greater emission surface with equal diameter, generating higher sound pressure. The compact 6-spoke aluminum alloy anti-resonant basket is the same as the top model ML 2500.3 and contributes to the subwoofer’s mechanical damping, being absolutely transparent to the sound.  The 65-mm 4-layer voice coil is higher than 60 mm and wound in a TIL-P former, thus delivering high linear displacement. The 4 Ω + 4 Ω DVC impedance configuration improves versatility to match any amplifier system. The air cooling and decompression system avoids the need for a centre hole on the bottom plate with three advantages:

– Better thermal inertia to ensure low operating temperatures during musical transients;
– Maximization of the magnetic field induced to the coil with the same overall motor dimensions. Thanks to a greater amount of iron in the pole the likelihood of magnetic saturation decreases exploiting the maximum flux density generated from the magnet;
– Possibility to install the subwoofer right on the box wall, taking full advantage of its minimal dimensions. A damping rubber disk, provided with the product, secures the subwoofer to the box and ensures air exchange for the 10 vents on the bottom.

The holes behind the voice coil winding and the 10 vents on the bottom plate ensure greater air exchange to the coil inner layers and work in synergy with an innovative assembly system. It forces the air to pass through the air gap to keep the coil operating temperature low, even with the most extreme musical programs. The terminal uses solid push connectors with an antishort circuit cover accepting cables up to 8 AWG to provide ultra-low wiring resistance in low impedance configurations (1ohm).

Features

1. Ergonomic, compact design, specifically developed for sealed box enclosures starting at 17 lt volume.
2. CCAW, 65 mm (2,5”) 4-layer voice coil, capable of handling 1200 W musical power. The 4 Ω + 4 Ω DVC impedance configuration improves versatility to match any amplifier system.
3. Voice coil wound on TIL-P material with venting holes behind the winding. This combines efficient heat dissipation with a high Qms factor (low mechanical loss) for bursting dynamic sound.
4. Exponential V-cone® with optimized geometry for high cone stiffness and strong resistance to deformation even at maximum excursions.
5. Boundary Free IIR rubber surround, for higher SPL performance while keeping a nominal external diameter.
6. Mineral-injected paper cone, for superior rigidity and damping.
7. Extremely acoustically transparent anti-resonant aluminium alloy basket with six-spokes standing structure and built-in venting holes underneath the spider.
8. CNC machined elegant diamond-cut basket edge featuring the Hertz logo.
9. Terminal block accepting cables up to 8 AWG to provide ultra-low wiring resistance in low impedance configurations. A plastic cover prevents any accidental short-circuit.
10. Possibility to secure the subwoofer to the box wall, taking full advantage of its minimal dimensions.
11. High performance compact motor with a superior magnetic field transferred to the coil.