Hertz MP 300 Review: 12-Inch Mille Pro DVC Sub in D4.3 and D2.3, Plus the MG 300.3 Grille

The Hertz MP 300 is a 12-inch (300 mm) dual-voice-coil subwoofer from Hertz's Mille Pro range, sold in two versions: the MP 300 D4.3 with two 4-ohm coils and the MP 300 D2.3 with two 2-ohm coils. Both are rated at 600 W continuous and 1,200 W peak with 86 dB sensitivity, and Hertz's sealed box for them is only 28 litres. Each version has an Indian MRP of ₹39,990, the same as the 10-inch MP 250. It suits owners who want serious 12-inch bass from a compact box. See the MP 300 D4.3 listing and the MP 300 D2.3 listing for today's prices.

Quick summary

• Same driver, two coil options: the D4.3 wires to 2 or 8 ohms, the D2.3 to 1 or 4 ohms. Choose by your amplifier.

• Hertz publishes a 28-litre sealed box and a 41-litre ported box, with suggested filter settings for each.

• A 164 mm mounting depth, and the sub can sit directly on the box wall on its supplied damping disk.

• No grille in the box; the MG 300.3 is the matching optional grille, and owner feedback so far is sparse.

Hertz MP 300 specifications

Specification	Hertz MP 300
Type	12-inch (300 mm) dual-voice-coil subwoofer
Versions	MP 300 D4.3 (4 + 4 Ω), MP 300 D2.3 (2 + 2 Ω)
Power handling	600 W continuous / 1,200 W peak
Sensitivity	86 dB
Voice coil	65 mm (65.5 mm on the D4.3), four-layer CCAW on a TIL-P former
Cone and surround	Pulp with mineral powders, V-cone profile; Boundary Free IIR rubber surround
Xmax / Xmech	D4.3: 17 / 27 mm; D2.3: 16 / 26 mm
Fs / Qts / Vas	D4.3: 24 Hz / 0.42 / 74 l; D2.3: 23 Hz / 0.48 / 88 l
Mounting depth	164 mm
Mounting hole (Hertz box designs)	287 mm
Weight	8.63 kg (D2.3; not listed for the D4.3)
Grille	Not included; MG 300.3 or MPG 300.3 optional
India MRP	₹39,990 for either version

Figures are from Hertz's MP 300 D4.3 and MP 300 D2.3 pages, which match our listings.

Dual voice coils: wiring each version

A dual-voice-coil sub has two windings on one former, so how you connect them sets the load your amplifier sees. Always drive both coils: in series, in parallel, or each from its own amplifier channel. Hertz says the layout is meant to match any amplifier.

Wiring	MP 300 D4.3	MP 300 D2.3
One sub, coils in series	8 Ω	4 Ω
One sub, coils in parallel	2 Ω	1 Ω
Two subs, each in series, then paralleled	4 Ω	2 Ω
Two subs, each in parallel, then paralleled	1 Ω	Half an ohm (avoid)

In practice: with one sub on a mono amplifier rated down to 1 ohm, the D2.3 in parallel extracts the most power; on an amplifier rated to 2 ohms, choose the D4.3 in parallel; on a 4-ohm-only amplifier, the D2.3 in series. For a pair, two D4.3s make 1 or 4 ohms and two D2.3s make 2 ohms. Never go below your amplifier's rated minimum load.

Enclosures: Hertz's sealed and ported designs

Hertz's sealed design is 28 litres with a 48 Hz system resonance, built 450 x 360 x 280 mm in 19 mm board, with a suggested 15 Hz subsonic and a 70 to 80 Hz low-pass, both at 24 dB/octave. In that box Hertz gives the D4.3 a Qtc of 0.82 against 1 for the D2.3, so in theory the D4.3 is slightly flatter and better damped there. The ported design is 41 litres tuned to 35.6 Hz, 620 x 390 x 330 mm, with a 352 x 60 mm slot port 744 mm long, a 20 Hz subsonic and a 60 to 70 Hz low-pass.

Both designs use a 287 mm mounting hole. Hertz also lets you mount the sub right on the box wall using the supplied damping rubber disk, which keeps air moving through the ten cooling vents in the bottom plate. The push terminals take cable up to 8 AWG and have an anti-short cover.

The MG 300.3 grille

Neither version ships with a grille, and Hertz lists the MG 300.3 and MPG 300.3 as optional. Our MG 250.3 / MG 300.3 grille listing sells both sizes: pick the MG 300.3 for this sub and the MG 250.3 for the 10-inch MP 250. Hertz describes the MG 250.3 as a cast aluminium ring with black steel mesh, hidden M5 screws and an included bit driver, but its MG 300.3 page says only that it is a Mille 300 mm subwoofer grille. In a boot where bags slide around, a grille is cheap insurance for the cone.

Amplifier pairing and power

Look for a mono amplifier that delivers up to about 600 W RMS at the load you wire for; Hertz's DP 1.500 is one mono Class D amplifier we stock, so check its rating at your chosen impedance. It draws serious current, so use proper power cable and fusing, and check the battery and alternator cope with the AC on at idle. Our guide to choosing a car amplifier covers the basics.

What owners and reviewers say about the Hertz MP 300

We found no professional review of this generation; this is the owner feedback we found when we checked in October 2026.

UK retailer Four Car Audio shows two top-rated reviews of the D2.3; the one with text, from February 2026, describes deep, authoritative bass with excellent control that stays musical when pushed. The page doesn't say how its reviews were collected or verified. On eBay, the D4.3 has a single five-star rating from June 2025 praising the build quality, written before the sub was installed. Crutchfield has a review page for the D4.3 that didn't load for us. That is not a consensus; if you run an MP 300, tell us how it sounds.

MP 300 vs MP 250 and other Hertz subs

The 10-inch MP 250 costs the same and shares the 600 W rating, but Hertz lists it at 83.5 dB against 86 dB, with smaller boxes (17 litres sealed, 24.5 litres ported) and a 141 mm mounting depth. If boot space is tight, Mille Pro also offers the shallow MPS 300 (₹49,990) and the ready-made MPBX 300 S2 enclosure (₹59,990).

The Cento CS 300 (₹19,990) is a cheaper 12-inch option: a single 35 mm voice coil, a polypropylene cone and 350 W continuous, with a slightly higher 86.5 dB rating. The MP 300's extra cost buys a 65 mm four-layer coil, 600 W continuous and dual-coil flexibility.

Who should buy it, and who shouldn't

Buy the MP 300 if you want a powerful 12-inch sub in a compact sealed box, have or plan a mono amplifier of around 600 W, and value being able to match its load exactly. Look elsewhere if your boot can't spare a 28-litre box, you want a ready-built enclosure, or your amplifier makes far less power.

Installation notes for Indian cars

Measure the boot first: the sealed box is 450 x 360 x 280 mm and the ported one 620 x 390 x 330 mm, which matters if a CNG cylinder takes space. Strap or bolt the box down for broken roads, and keep the vents under the magnet clear in summer heat. VA3 Car Studio in Ghaziabad offers professional installation.

Price and where to buy

The MP 300 D4.3 and MP 300 D2.3 each carry an MRP of ₹39,990, and the MG 250.3 / MG 300.3 grille listing is ₹4,990. VA3 Car Studio often sells below MRP, so check the current offers on the D4.3 (4 + 4 ohm) page, the D2.3 (2 + 2 ohm) page and the MG grille page.

Check today's price at VA3 Car Studio

The bottom line

The Hertz MP 300 packs a 65 mm four-layer coil and 600 W continuous handling into a sub that Hertz pairs with a 28-litre sealed box, and the two coil options let you match almost any mono amplifier. Owner feedback is thin, so pick the version by your amplifier, follow Hertz's box designs, and add the MG 300.3 if the cone will be exposed.

Hertz MP 300 FAQ

Should I buy the Hertz MP 300 D4.3 or D2.3?

Choose by your amplifier. One D2.3 wires to 1 or 4 ohms and suits 1-ohm-stable or 4-ohm mono amplifiers; one D4.3 wires to 2 or 8 ohms and suits 2-ohm amplifiers. For two subs, D4.3s give 1 or 4 ohms and D2.3s give 2 ohms.

What box does the MP 300 need?

Hertz publishes a 28-litre sealed box with a 48 Hz system resonance and a 41-litre ported box tuned to 35.6 Hz with a 352 x 60 mm port 744 mm long. Both use a 287 mm mounting hole and 19 mm board.

Does the MP 300 come with a grille?

No. Hertz lists the MG 300.3 and MPG 300.3 as optional grilles. We sell the MG 300.3 through our MG 250.3 / MG 300.3 listing, where you choose the 300 mm size for this subwoofer.

Buy the Hertz MP 300 D4.3 Mille Pro in India

You can buy the Hertz MP 300 D4.3 Mille Pro online from VA3 Car Studio with pan-India shipping. See more Hertz subwoofers, compare other car subwoofers, or book subwoofer installation in Ghaziabad.