In this Article: We will provide an in-depth review of the Hertz Mille Pro subwoofers and the key features we think are important for those interested in purchasing and installing one of Hertz’s MPS subwoofers.

Hertz Mille Pro Shallow Subwoofer Feature Overview

Hertz products have been on our list of best car subwoofers and best car speakers for nearly a decade now. We’ve been installing Hertz products since the late 2000s and have watch them become a mainstream, high-end product lineup in the U.S. The Mille Pro Subwoofers are yet another example of why we’ve been a fan of Hertz for so long!

The Hertz Mille Pro series lineup includes coaxial and component speakers along with a range of subwoofers to provide a whole car entertainment system. The newest model in the lineup is the Mille Pro Shallow or MPS. The Hertz MPS subwoofers are designed from the ground up to take advantage of numerous technologies to enhance the bass in your car while retaining a compact package that is ideal for use beneath rear bench seats in trucks or in any other location where space is at a premium. Hertz MPS subwoofers are available in 10-inch and 12-inch designs and offer either two-ohm or four-ohm resistance values to optimize your system.

Compact Design Features

One of the key reasons why consumers would look to the MPS subwoofers for their system is obviously the incredibly compact design, which allows the subwoofer to be installed in tight spaces. The new 10 inch MPS design measures only 3 1/4 inches deep when mounted compared to 5 9/16 inches required by the concurrent Mille Pro subwoofer design. That matches JL Audio’s 10TW3 in terms of depth, which has always been one of our go-tos for super compact subwoofers.

Most shallow-mount subwoofers are a compromise between power output and space often with predictably disappointing results though. That’s not the case with the MPS. Hertz claims the design offers 20 percent more cone excursion capacity compared to the MP subwoofer. A special suspension design aids the subwoofer in achieving excellent results while remaining relatively shallow compared to other subwoofers.

Hertz calls the technology “smart suspension group design” which moves the magnet group up and allows the subwoofer to function like a traditional full-depth subwoofer.

Air Intercooling Revolution

Hertz Air Intercooling Revolution AIR

Air intercooling revolution (AIR) technology provides a pathway for airflow to prevent internal air compression while ensuring maximum cooling airflow to the magnet and motor structure. The AIR design produces ideal fluid dynamics of the inner acoustic structure for maximum power handling. This design keeps the subwoofer operating within the thermally stable range of temperatures to enhance bass output.

Six-Layer Voice Coils

hertz mps 6 layer voice coil

Voice coils using more numerous layers are intended to reduce overheating by providing more surface area that allows a larger space for heat to be absorbed. The downside of a multi-layer voice coil is the reduction in frequency range above 500 Hz which is not an issue for these subwoofers since they aren’t intended for midrange performance.

The MPS series of subwoofers use single voice coils in 2-ohm and 4-ohm variants. The single design helps to reduce the overall size of the subwoofer. The standard MP subwoofers are available with dual voice coils.

Finite Element Method (FEM) Modeling

The magnet assembly has been modeled using Finite Element Method modeling, which allows the sound engineers at Hertz to custom tailor the sound by using dozens of complex calculations to ensure the proper sound production even at high power handling ratios.

The pole piece has also been fully modeled to produce a design that improves unit force factor thereby improving overall sound quality and balance throughout the range of the subwoofer’s capabilities. By focusing on using the most modern modeling techniques, the engineers at Hertz have built a compact subwoofer that punches well above its size.

Engineered for Compact Boxes

The MPS subwoofers include a woofer cone and spider design that was extensively tested by the R&D engineers at Hertz to ensure that the assembly functions perfectly in the confines of a compact sealed box. The design allows these speakers to be mounted in spots that almost no other subwoofer will fit and still sound like a proper, full-size sub.

Hertz compact sealed boxes

Not only have these subwoofers been modeled and designed to ensure optimal performance in a sealed box, but Hertz also even builds their own sealed designs to provide up firing or down firing performance. The boxes feature special internal baffle and support structures that prevent resonance and distortion while maximizing the volume output of the subwoofer. The boxes offer rounded corners to make installation easy too.

Woofer Cone, Spider, and Surround

The woofer cone of the MPS subwoofers is made from layers of compressed paper that has been injected with minerals to produce a strong, light structure that provides enough dampening to avoid resonance and ensuring accurate, tight bass even while running lots of power.

The unique design of the spider allows the woofer cone to move more than other similarly sized subs, producing deeper and more full bass while remaining compact in depth. The design sits higher up on the magnet structure than other designs, allowing the cone to remain centered no matter how much power is fed.

The surround is a rubber foam construction that is durable but also soft enough to allow the MPS subwoofers to achieve higher-than-average excursion rates.

eID – Elettromedia Identification

We thought this was a cool feature that only a few manufacturers do today with their speakers and subwoofers. The MPS subwoofers provide eID information you can use to trace the build of your speaker throughout its construction. You’ll see the results of every step of the process including the testing of the speaker that ensures it is performing as it should when it leaves the factory. Every MPS subwoofer has a QR code that you can scan to learn all about your speaker.

Key Features

  • Ultra-shallow overall depth
  • Available in 10” and 12” sizes with options for 2 or 4-ohm resistance
  • Optimized for extremely compact sealed enclosure 12-14L (0.4-0.5CF)
  • Air Intercooling Revolution (A.I.R.) prevents air-compression-related limitations
  • Unrivaled mechanical excursion, +20% over traditional designs
  • Six-layer copper voice coil (38mm/1.5 in.) ensures high thermal capacity
  • Non-vented rear design allows reduced enclosure depth
  • Robust screw-less mesh grille included with black screws provided
  • Die-cast aluminum frame
  • Solid horizontal 8AWG spring-loaded terminals
  • EID: Scan, Discover, Identify

Frequently Asked Questions (FAQs)

Will the MPS perform as well as the MP with the same amplifier?

The MPS is designed to work in a compact enclosure and uses special features to maximize the excursion so that you’ll get deep, hard-hitting bass from the subwoofer equal to that which you will get from the full-size MP subwoofer.

What is the difference between two-ohm and four-ohm options?

Two-ohm resistance subwoofers produce somewhat punchier bass and are typically louder than the four-ohm version. Four-ohm versions produce deeper, cleaner-sounding bass. You’ll also want to use two-ohm speakers in series when connected to a four-ohm amplifier.

Will this subwoofer function in a ported or free-air setup?

The MPS subwoofers are designed for sealed boxes and will work with many ported box designs. These subwoofers require the ability to use the air in a box for bass resonance, so they are not intended for free-air systems.

Can this subwoofer be bottom-mounted?

Yes, the Mille Pro Shallow subwoofer can be bottom-mounted. The subwoofer depth when bottom-mounted will increase to slightly over four inches.


The Hertz Mille Pro Shallow continues in the tradition of the Hertz Mille Pro line, using proprietary technology and extensive modeling to ensure the most powerful and hard-hitting bass frequencies while maintaining high sound quality. Up until now, we’ve leaned heavily on JL Audio’s TW3 and TW5 designs for ultra-shallow subwoofers like this, but the MPS series is a serious contender to the legendary TW3 subwoofer design. The Mille Pro Shallow is an ideal choice for mounting beneath the seat of a pickup truck or in the trunk of smaller cars without taking up all the space. We have had good success with he Mille Pro subwoofers and believe the new MPS design will become one of the most popular subwoofer designs to mount in places where an ultra-compact box is necessary.