Music fans who attend live concerts know well the emotions that low undistorted frequencoes without dynamic compression can arouse.

For this reason, the HertzAudioVideo R&D created Mille car audio subwoofers

Mille PRO Shallow Subwoofers

Mille PRO shallow subwoofers have been designed to achieve exceptional performance even when there is very little space available to install the subwoofer box.

The subwoofers are optimized to work in ultra-compact sealed boxes starting from only 14 Lt (0.49 Cf) for 10′ models (MPS 250) and 22,7 (0.8 Cf) for 12’models (MPS 300). A typical example is a subwoofer enclosure under the rear bench of pickup trucks, where the space – and the height – are limited.

The new MPS (Mille PRO Shallow) subwoofers have a depth/performance ratio never achieved before thanks to the impressive cone excursion capacity which is 20% higher than a traditional design.

This exceptional target has been achieved thanks to the smart suspension group design featuring a dedicated support structure for spider and coil. This solution has allowed to move the magnetic group inwards, reducing the depth and at the same time maximizing cone linear excursion.

500 W continuous power handling is an incredible result for such a compact subwoofer. To accomplish this ambitious goal, the Hertz R&D has developed the proprietary AIR (Air Intercooling Revolution) technology, optimizing the fluid dynamics of the inner acoustic structure and the magnetic group to minimize the internal compression of air and maximize cooling capacity. The 6 layers, 1.5 in. (38 mm) voice-coil with cooling openings on the former contributes to the thermal stability of the subwoofer, making MPS subs ready to face to most demanding high-spl listening session.

The design of the magnetic unit has been FEM simulated to maximize force factor (BxL) symmetry and thus obtain an optimal linearity even at high excursions, perfectly controlling the inductance modulation.

Pole piece geometry has been optimized using a breakthrough simulation model that allowed improving unit force factor.

Hertz R&D also focused on modeling the cone/enclosure behavior: inside a sealed box, air behaves like a spring – a non-linear suspension – whose effect must be compensated to obtain a system as linear as possible at high excursions.

Model lineup

The lineup includes two sizes, 10 and 12 in., each one available in 2Ω or 4Ω voice coils configuration, removing all barriers to creativity with custom installations.

Hertz Mille PRO Shallow Subwoofer MPS 250 grille
Hertz Mille PRO Shallow Subwoofer MPS 250 grille
Shallow 8-spoke aluminum alloy anti-resonant basket

Mille PRO Shallow Subwoofer Boxes

Mille PRO ultra-shallow sealed enclosure are specifically optimized to deliver all the MPS subwoofer performances providing breathtaking low frequency from a box that is only 160 mm (6.3 in.) deep for MPBX 250 S2 and 175 mm (6.89) for MPBX 300 S2.

They are the Ideal choice to be installed under the rear bench of pickup trucks and generally where the space – and the height – are limited.

Hertz R&D department meticulously design the perfect sealed enclosure for MPS 250 S2 and MPS 300 S2 shallow-subwoofer using the most advanced technologies and massive in-car listening sessions to fine-tune the sound.

The panel-to-panel internal bracing on all sides of the box featuring solid corners minimize resonances. The internal sound-absorbing material virtually increase the volume of the box and further damp acoustic resonances. The 15 mm (0,59 in.) wood thickness provides an incomparable robustness.


2S² (2 Sides/2 Sounds) design provides the ability to choose between up-firing install to obtain more punch and definition and down-firing mounting, through supplied feet with Hook-and-loop inserts , to increase the low-frequency extension.


Thanks to SSP (Sub Smart Plug), MPBX feature both Plug-&-Play terminal block and traditional push terminals providing bulletproof connection and quick release.

The robust screw-less mesh grille is included, and the round corners ease the placement.

MP 250.3 Mille PRO features V-cone® and Boundary Free Surround technologies.

Mille PRO Subwoofers

Outstanding performance in a compact size, this is Mille Pro Subwoofer’s target. 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 Mille Pro 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 ML2500.3 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 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). The chart shows the connection diagram for each impedance configuration.

MP 250.3 Mille PRO: 4 layers massive Voice-Coil

MP 250.3 Mille PRO: central pole without hole

MP 250.3 Mille PRO former with venting holes

Model lineup

The use of the most sophisticated FEA (Finite Element Analysis) simulation tools allowed the identification of ideal design solutions for the designated target: outstanding performance in a compact size. The lineup includes two sizes, 10 and 12 in., each one available in 2Ω + 2Ω or 4Ω + 4Ω double voice coils configuration, removing all barriers to creativity with custom installations.

MP 250 with optional grill MPG 250, also available for MP 300 (MPG 300)

eID (Elettromedia Identification) provides the traceability of the

Mille.3 products from their birth on.

eID (Elettromedia Identification) is the exclusive technology providing the traceability of the Mille.3 products from their birth on.

Once the test phase has been passed, the code linked to destination country/market is applied. When purchasing the product, by scanning the code, the user can check through the web the information about the product and can log into the registration page; by filling it out, the user will be entitled to one additional year of warranty coverage*.

This way the user will have the certainty of owning a genuine Hertz product, purchased through the official channel.

*in those countries where the agreement with the partner has been made.