The Best Soundbar Setup You Can Buy Right Now — No Receiver Needed
If you've been looking for the ultimate two-piece home theater system that sounds like a cinema without the wires, receivers, or ceiling work — you've found it. The Sonos Arc Ultra paired with the Sub 4 is the answer most premium audio buyers in India have been waiting for.
At 8mm, we've installed and evaluated hundreds of home theater systems across 8+ states. When we tell you the Sonos Arc Ultra + Sub 4 combo is something special, it comes from years of hearing what "good" actually sounds like in a living room.
Let's break down exactly what you get — and whether it justifies the price.
What's in the Box: Sonos Arc Ultra + Sub 4
The Sonos Premium Entertainment Set bundles Sonos's flagship soundbar with their most capable wireless subwoofer:
- Sonos Arc Ultra — A 9.1.4-channel Dolby Atmos soundbar with 14 custom-engineered drivers
- Sonos Sub 4 — A wireless subwoofer with dual 5" × 8" force-cancelling elliptical woofers
- HDMI eARC cable, power cables, and quick-start documentation
Both units are available in Matte Black or White, and the packaging is 100% recyclable.
Sonos Arc Ultra: A Soundbar Built Around Dolby Atmos
Driver Configuration
The Arc Ultra is no ordinary soundbar. Inside its slim 1.18-metre chassis sit 14 custom Sonos drivers, each powered by its own Class D amplifier:
- 7 silk dome tweeters (2 upward-firing for Atmos height)
- 6 midrange drivers for imaging and dialogue
- 2 oval woofers with the new Sound Motion technology
The result is a native 9.1.4 audio configuration — something that typically requires at least 13 separate speakers in a traditional setup. The Arc Ultra delivers that from a single bar sitting under your TV.
Sound Motion Technology — The Real Breakthrough
The biggest upgrade over the original Sonos Arc is the proprietary Sound Motion driver system, which uses a uniquely compact but deeply excursive woofer design. This allows the Arc Ultra to produce genuinely powerful, low-reaching bass from a slim profile — something previous soundbars at this size category simply couldn't do. The Arc Ultra can hold its own down to the 50–60 Hz range on its own, which means even without the Sub 4, this soundbar sounds richer and fuller than most competitors in its class.
Dolby Atmos Performance
The Arc Ultra supports the full Dolby Atmos signal chain — Dolby Digital Plus, Dolby Atmos via HDMI eARC, and Dolby TrueHD. Connect it to your TV's HDMI eARC port and you're getting full-resolution spatial audio from services like Netflix, Amazon Prime Video, Disney+, and Apple TV+.
What makes this special is what Sonos calls "custom colinear waveguides" on the left, centre, and right channels, along with optimised up-firing and side-firing drivers that bounce sound off your walls and ceiling to produce a convincing overhead and surround effect. In real-world use with content like Interstellar or Dune, the height channels feel genuinely placed — not simulated.
Dialogue clarity is another area where the Arc Ultra sets itself apart. A dedicated centre channel combined with Sonos's Speech Enhancement mode (with four levels of vocal clarity adjustment) means voices stay crisp even during the loudest action sequences.
Note: The Arc Ultra does not support DTS via a licensed decoder. DTS content passes through in a downmixed format. If your library is primarily Dolby Atmos, this is not a concern.
Connectivity
- HDMI eARC (required for full Dolby Atmos)
- Wi-Fi 6 (802.11ax, 2.4 GHz and 5 GHz)
- Bluetooth 5.3
- Apple AirPlay 2
- Alexa and Sonos Voice Control
- No optical input, no additional HDMI inputs
Sonos Sub 4: Force-Cancelling Bass That Feels Effortless
The Sub 4 is not your typical rectangular subwoofer. Sonos uses a force-cancelling driver alignment — two 5" × 8" elliptical woofers positioned face-to-face inside the cabinet. When they fire simultaneously in opposite directions, the vibrations cancel each other out. The result: extremely low distortion at high output, with virtually no cabinet resonance or "buzzing" feel.
Two Class D amplifiers power these drivers, and the Sub 4 pairs wirelessly to the Arc Ultra via NFC — typically in seconds. No cables required between the two units.
What the Sub 4 Actually Adds
The Arc Ultra already produces surprisingly capable low-end on its own. So what does adding the Sub 4 do?
It adds precision. When you remove bass responsibility from the Arc Ultra by handing it to the Sub 4, the soundbar's midrange and dialogue reproduction become even cleaner. The overall bass becomes more articulate — you feel the difference between a bass guitar and a kick drum, between an explosion and a deep rumble. For music listening, this integration is seamless. Sonos's engineers have resisted the temptation to over-boost low frequencies, resulting in tight, accurate bass that serves the content rather than overwhelming it.
For large rooms and high-volume use, the Sub 4 transforms the system from impressive to immersive.
Setup: Under 15 Minutes, Seriously
The Sonos Arc Ultra + Sub 4 setup is guided entirely through the Sonos app on iOS or Android. Connect the Arc Ultra to your TV's HDMI eARC port, power it on, open the app, and follow the prompts. The Sub 4 pairs automatically.
Once both are connected, Trueplay room calibration kicks in — the system uses your device's microphone to measure your room's acoustics and adjusts the EQ and speaker output accordingly. The difference before and after Trueplay is audible, especially in rooms with mixed surfaces.
Total setup time in real-world conditions: 10–15 minutes.
Sonos App: Controls at Your Fingertips
Once set up, the Sonos app gives you full control over:
- Bass, treble, and loudness EQ
- Sub level (adjust how much low-end the Sub 4 contributes)
- Height channel level (increase Atmos overhead effect to taste)
- Speech Enhancement (4 vocal clarity levels)
- Night Sound mode (reduces peaks for late-night use)
- Trueplay re-calibration anytime
This level of fine-tuning from a mobile app puts the Arc Ultra + Sub 4 in a different category from most soundbars, which offer basic volume and bass toggle at best.
Expandability: This Is a Platform, Not Just a Soundbar
One of the most compelling arguments for the Sonos Arc Ultra + Sub 4 is where it can go from here. The Sonos ecosystem allows you to add:
- Sonos Era 100 or Era 300 as wireless rear speakers for true surround sound — turning the Arc Ultra into a full Dolby Atmos 7.1.4 system
- Sonos Ace headphones with TV Audio Swap for private listening without leaving the ecosystem
- Additional Sonos speakers throughout your home for whole-house multi-room audio
This means your investment today isn't a dead end — it's a foundation.
Technical Specifications
| Feature | Sonos Arc Ultra | Sonos Sub 4 |
|---|---|---|
| Audio Channels | 9.1.4 | — |
| Drivers | 14 (7 tweeters, 6 mid, 2 woofer) | 2 × 5" × 8" elliptical |
| Amplification | 15 × Class D | 2 × Class D |
| Connectivity | HDMI eARC, Wi-Fi 6, BT 5.3 | Wi-Fi, Ethernet |
| Supported Formats | Dolby Atmos, Dolby TrueHD, Dolby Digital Plus, DTS Digital Surround, PCM | — |
| Special Tech | Sound Motion, Trueplay, Colinear Waveguides | Force-cancelling driver array |
| App Control | Sonos App (iOS & Android) | Sonos App |
| Voice Assistants | Alexa, Sonos Voice Control | — |
| Wireless Pairing | — | NFC auto-pair |
| Finish | Matte Black / White | Matte Black / White |
| Price (India) | ₹1,79,900 (combo) | Included in set |
Who Should Buy the Sonos Arc Ultra + Sub 4?
Buy it if you:
- Want a serious Dolby Atmos home theater without a receiver, AV rack, or ceiling speakers
- Value clean design and want the system to disappear into your living room
- Watch a lot of streaming content on Netflix, Prime Video, or Apple TV+
- Want a system that doubles as a premium music speaker
- Plan to expand your system later with surround speakers
Consider alternatives if you:
- Watch a lot of DTS-encoded Blu-ray or content (the Arc Ultra does not have a licensed DTS decoder)
- Need multiple HDMI inputs — the Arc Ultra has only one (eARC)
- Have a room under 200 sq. ft. (the Sub 4 may feel overwhelming without EQ adjustment)
Our Verdict at 8mm
The Sonos Arc Ultra + Sub 4 Premium Entertainment Set is the most refined, best-sounding wireless home theater system in a two-piece form factor available in India today. The build quality, acoustic engineering, and ecosystem depth make it worth serious consideration for anyone investing in their living room audio.
At 8mm, we carry and recommend this system for customers who want the cinema experience at home — without the complexity of a traditional AV setup. If you'd like to experience it before buying, visit our experience centre in Shankar Nagar, Raipur, or get in touch with our team for a personalised consultation.
Frequently Asked Questions
Q: Does the Sonos Arc Ultra support Dolby Atmos?
Yes. The Sonos Arc Ultra supports Dolby Atmos via HDMI eARC, including Dolby Atmos from Dolby Digital Plus and Dolby TrueHD sources. You'll need a TV with an HDMI eARC port to unlock full Atmos decoding.
Q: Is the Sub 4 necessary with the Arc Ultra?
 Not strictly — the Arc Ultra's Sound Motion woofers make it surprisingly capable on its own. However, adding the Sub 4 improves bass precision, depth, and overall scale significantly, especially for movies and large-room use. The Arc Ultra + Sub 4 combo is strongly recommended for the best experience.
Q: Does the Sonos Arc Ultra support DTS?
The Arc Ultra does not include a licensed DTS decoder. It can pass DTS Digital Surround content but does not decode DTS:X or DTS-HD Master Audio. If your home theater library is primarily Dolby Atmos content (streaming or Blu-ray), this won't be an issue.
Q: How does the Sonos Sub 4 connect to the Arc Ultra?
The Sub 4 pairs wirelessly to the Arc Ultra using NFC auto-pairing through the Sonos app. No audio cables are needed between the two units. Both connect to your home Wi-Fi network independently.
Q: Can I add surround speakers to this system later?
Yes. The Sonos Arc Ultra + Sub 4 can be expanded by adding Sonos Era 100 or Era 300 speakers as wireless rear channels, turning the setup into a full Dolby Atmos 7.1.4 home theater without any additional wiring.
Q: What TV connection does the Arc Ultra use?
The Arc Ultra connects via a single HDMI eARC port. This is the only AV input on the soundbar. A TV with HDMI eARC (not just ARC) is required for full Dolby Atmos support.
Q: How does Trueplay work and do I need it?
 Trueplay is Sonos's automatic room calibration technology. After setup, the Sonos app uses your phone's microphone to measure how sound behaves in your specific room and adjusts the Arc Ultra and Sub 4's output accordingly. It works on both iOS and Android and makes a noticeable improvement in most rooms. It is highly recommended.
Q: Is the Sonos Arc Ultra + Sub 4 available in India?
 Yes. The Sonos Premium Entertainment Set (Arc Ultra + Sub 4) is available in India through 8mm, priced at ₹1,79,900.
Q: Can I use the Arc Ultra for music streaming as well?
 Absolutely. The Arc Ultra supports Apple AirPlay 2, Bluetooth 5.3, and directly streams from services like Spotify, Apple Music, and Amazon Music through the Sonos app. It functions as a high-quality music speaker independently of your TV.
Q: How does the Sonos Arc Ultra compare to the original Sonos Arc?
The Arc Ultra delivers significantly more bass thanks to the new Sound Motion woofer technology, a more refined Dolby Atmos presentation with updated colinear waveguides, improved dialogue clarity, and a 9.1.4 vs 5.0.2 driver count. It also supports Wi-Fi 6 and Bluetooth 5.3 vs the older Arc's Wi-Fi 5.
Experience It Before You Buy
The best way to know if the Sonos Arc Ultra + Sub 4 is right for your space is to hear it. Visit the 8mm Experience Centre in Shankar Nagar, Raipur — India's premier dedicated audio-video showroom — where our specialists can walk you through a full demonstration and help you compare it with alternatives.
Shop the Sonos Arc Ultra + Sub 4 Premium Entertainment Set →
Or call us at +91 7440790337 / email contact@8mm.in
Written by Yug Gupta | Audio Specialist at 8mm.in
