Hertz DP 4.400 Review: 75 W x 4 Hi-Res Class AB Amp for 100 W Speakers
Updated: Oct 6
The Hertz DP 4.400 is the more powerful of the two Dieci Power four-channel Class AB amplifiers we sell, rated at 75 W x 4 into 4 ohms, 105 W x 4 into 2 ohms or 210 W x 2 bridged, at 14.4 V and 1% distortion. Like its smaller sibling it is Hi-Res Audio certified, with a 10 Hz to 45 kHz response, speaker-level inputs and automatic turn-on for factory head units. Its Indian MRP is ₹30,990, the highest of the three DP amplifiers we sell. It suits component sets rated around 100 W, or a front stage plus a subwoofer from a single amplifier. See it on our Hertz DP 4.400 product page.
Key points
75 W x 4 at 4 ohms and 210 W x 2 bridged at 1% distortion, with Hertz quoting 0.01% distortion at 70% of rated power.
Two-ohm stable per channel and bridgeable at 4 ohms, including a three-channel mode for speakers plus a sub.
Factory-friendly: speaker-level inputs, automatic turn-on and full-range front pre-outs.
No owner reviews or professional tests turned up, so judge it on Hertz's published figures.
Hertz DP 4.400 specifications
Specification | Hertz DP 4.400 |
|---|---|
Type | 4-channel Class AB, Hi-Res Audio certified |
Power, 14.4 V, 1% THD | 75 W x 4 at 4 Ω; 105 W x 4 at 2 Ω; 210 W x 2 bridged at 4 Ω |
Three-channel mode | 75 W x 2 at 4 Ω plus 210 W x 1 bridged at 4 Ω |
Power, 14.4 V, 10% THD | 90 W x 4 at 4 Ω; 125 W x 4 at 2 Ω; 250 W x 2 bridged |
Minimum load | 2 Ω per channel; 4 Ω bridged |
Frequency response | 10 Hz – 45 kHz |
Crossovers | High-pass and low-pass: 50–4000 Hz, 12 dB/octave |
Bass boost | 0–9 dB |
Inputs | Pre-in 0.32–8 V RMS; speaker-in 1.6–40 V RMS |
THD / S/N / damping factor | 0.01% / 101 dBA / 130 |
Efficiency | 60% |
Supply / fuses | 11–15 V DC / 2 x 25 A |
Size / weight | 335 x 190 x 50 mm / 2.88 kg |
India MRP | ₹30,990 |
Figures are from Hertz's DP 4.400 page. Hertz doesn't give a centre frequency for the bass boost, so we haven't quoted one.
What the power ratings mean
At 75 W into 4 ohms, the DP 4.400 has 25% more power per channel than the 60 W DP 4.300. In loudness terms that is about 1 dB, a small but useful amount of extra headroom before clipping. Bridged output rises by a similar proportion, from 170 W to 210 W, and Hertz's published refinement figures improve too: 0.01% distortion against 0.015%, a 101 dBA signal-to-noise ratio and a damping factor of 130 against 105.
Hertz also publishes a total-power figure of 1,000 W. It is exactly double the 4 x 125 W quoted at 2 ohms and 10% distortion, so it tells you nothing about what each speaker receives. Use the 1% figures when matching speakers.
Speakers, subwoofers and three-channel mode
This is the DP model for component sets rated near 100 W continuous, such as Hertz's Cento CK 165 (95 W continuous) or Cento Pro CPK 165 (105 W continuous). Use the four channels for front and rear speakers, or for an active two-way front stage controlled by a DSP.
In three-channel mode it drives two speaker channels at 75 W each and puts 210 W into a 4-ohm sub on one bridged channel; check Hertz's manual for which pair to bridge. That suits a 4-ohm sub such as the MPS 250 S4, although that is well under the driver's 500 W rating, so the sub won't be driven to its full rating. For 2-ohm subs or serious bass, add the mono DP 1.500, which makes 500 W at 2 ohms.
Inputs, filters and factory systems
The speaker-level input accepts 1.6 to 40 V, and Hertz says the amplifier can turn itself on and off from the factory speaker outputs, so cars keeping their factory touchscreen don't need a remote lead. Hertz describes both inputs as balanced, with its Universal Speakers Simulator for compatibility, and an aftermarket head unit's RCA outputs (0.32 to 8 V) work too. Full-range front pre-outs can feed another amplifier.
High-pass and low-pass filters run from 50 Hz to 4 kHz at 12 dB per octave, with up to 9 dB of bass boost. These are enough for a simple passive system; for time alignment and per-speaker tuning, a DSP does the job better, as our guide on the need for a DSP explains.
What owners and reviewers say about the Hertz DP 4.400
We checked in October 2026 and found no owner reviews or professional tests of the DP 4.400, so there is no consensus to report.
The only owner feedback we found in the DP range is for the mono DP 1.500, summarised in our DP 1.500 review; it doesn't tell you how this amplifier performs. Until reviews appear, the specifications above are the verifiable basis for a decision. If you've installed a DP 4.400, we'd like to hear about it.
DP 4.400 vs DP 4.300 and DP 1.500
The DP 4.300 is ₹10,000 cheaper at ₹20,990 MRP and smaller, at 290 mm long and 2.43 kg against 335 mm and 2.88 kg. For speakers rated around 60 to 80 W, its 60 W x 4 is enough. Choose the DP 4.400 for 100 W-class speakers or a stronger bridged sub channel.
The DP 1.500 (₹24,990 MRP) is a different tool: a Class D mono amplifier for subwoofers. A DP 4.400 for the speakers and a DP 1.500 for the sub gives a complete amplifier set-up from one range.
Who should buy it, and who shouldn't
Buy the DP 4.400 if your speakers are rated near 100 W continuous, you want headroom for an active two-way front stage, or you want speakers plus a 4-ohm sub from one amplifier.
Look elsewhere if your speakers are rated well under 100 W, where the DP 4.300 saves money and space, or if bass is the priority, where a DP 1.500 with a 2-ohm sub makes more sense.
Installation notes for Indian cars
At 60% efficiency, this Class AB amplifier turns a good share of the power it draws into heat, and a boot in an Indian summer is already hot. Mount it with air around it, under a seat or on a panel, never under carpet or luggage. Hertz rates it for -20 to 60 °C, and at 335 mm long it needs a flat mounting area.
Hertz gives its consumption at 14.4 V into 2 ohms as 30 A at maximum musical power, so don't treat that as a ceiling. It idles at 0.85 A and uses two 25 A fuses, so it needs a properly sized, fused power cable and a good earth. Hertz says it operates from 6.5 to 16.5 V, which should help in traffic when voltage sags with the AC on. Our guide on why a car system needs an amplifier covers the basics, and VA3 Car Studio in Ghaziabad can plan, install and tune the system.
Price and where to buy
The Hertz DP 4.400 has an MRP of ₹30,990 in our current Indian listing. Check today's price and stock on the DP 4.400 product page, and ask us to suggest matching speakers. Every amplifier we sell is a genuine Hertz product.
The bottom line
The DP 4.400 gives Hertz's Dieci Power range a four-channel with more headroom: 75 W x 4 and 210 W bridged, plus the same Hi-Res certification and factory-system inputs as the DP 4.300. Its advantages over the DP 4.300 are real but modest on paper, so buy it for 100 W-class speakers or a bridged sub. We found no owner reviews, so mount it with care for heat and judge it on the published figures.
Hertz DP 4.400 FAQ
Is the Hertz DP 4.400 worth it over the DP 4.300?
It gives 75 W instead of 60 W per channel at 4 ohms, about 1 dB more, plus 210 W instead of 170 W bridged and better published distortion and damping figures, for ₹10,000 more. For speakers rated around 60 to 80 W, the DP 4.300 is enough.
Can the DP 4.400 power a subwoofer?
Yes. In three-channel mode it gives 75 W x 2 to two speaker channels and 210 W to a 4-ohm sub on one bridged channel. A bridged channel needs at least 4 ohms, so use a mono amplifier for a 2-ohm sub.
How much current does the DP 4.400 draw?
Hertz lists 30 A of consumption at 14.4 V into 2 ohms at maximum musical power, so don't treat that as a ceiling. Idle current is 0.85 A, and it uses two 25 A fuses, so plan a correctly sized power cable with its own fuse near the battery.
Buy Hertz Amplifiers in India
You can buy the Hertz DP 4.400 4-Channel Class AB Car Amplifier 500W online from VA3 Car Studio with pan-India shipping. See more Hertz amplifiers, compare other multi-channel amplifiers, or book amplifier installation in Ghaziabad.
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