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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-09-21 · 7 min read · Independent comparison
• Avantree Relay & Clan biggest strength: it separates the wireless part from the listening part. The Relay is a Bluetooth 5.3 transmitter with a dual 3.5mm adapter, so it plugs into a plane's AUX jack, a gym machine or a TV and sends audio to whatever Bluetooth earbuds or headphones you already carry.
• Avantree Relay & Clan biggest trade-off: the included earbuds top out at up to 24dB of hybrid ANC, which is modest next to a full over-ear design, and the whole kit only makes sense if you own (or plan to own) Bluetooth listening gear.
• Hmusic MS04 biggest strength: a 4-mic hybrid ANC system rated at up to 40dB of noise reduction, plus up to 80 hours of playback (50 with ANC on) and a foldable over-ear build with a travel case.
• Hmusic MS04 biggest trade-off: it is a single pair of headphones weighing 270g, it cannot stream Bluetooth while wired (ANC and buttons shut off in wired mode), and it has no transmitter function at all.
• Who each is for: Avantree Relay & Clan is for frequent flyers and commuters who already love their own earbuds. Hmusic MS04 is for people who want one pair of big, quiet, long-lasting headphones for the whole trip.
The Relay is best understood as a bridge, not a pair of headphones. It outputs audio over Bluetooth 5.3 and pairs with essentially any Bluetooth headphone or earbud you own. On the other end it takes audio in through a 3.5mm AUX connection, and the included dual 3.5mm adapter means it works on flights regardless of which connector type the seat has. That one detail is the reason I think frequent flyers should care: you stop gambling on whether your gear fits the armrest socket.
Codec support matters here too. With aptX-Adaptive, the Relay can send high-quality audio at low latency to listening devices that support the codec, which is exactly what you want for lip-sync on a seatback movie or a show on a hotel TV. Where the kit goes beyond a plain transmitter is the bundled earbuds: hybrid ANC rated to block up to 24dB of environmental noise, an Ambient Mode that pipes the built-in mics back in so you can hear announcements or traffic, and a charging case with a battery display so you can see levels and charging status at a glance. The color is orange, and the stated minimum operating system version is iOS 13.
Hmusic MS04: Who It's For
The MS04 is the opposite philosophy: one self-contained pair of over-ear headphones that tries to cover the entire trip. The headline number is the noise cancelling. Four microphones (two internal, two external) drive a hybrid ANC system rated to reduce ambient noise by up to 40dB, and the brand's own description frames that against real-world noise floors: roughly 65–85dB on planes, 75–100dB of subway track friction, 60–75dB of cafe chatter. The claim is that ANC pulls your environment down toward 70dB so music stays clean and your ears get a break. There's also a Transparency Mode for when you need to hear what's happening around you.
Battery is the other big story. A full charge takes 3.5 hours and is rated for up to 80 hours of playback, or 50 hours with ANC on. A 30-minute top-up is rated at 20 hours of listening. For a long-haul itinerary, that's the kind of number that means you stop thinking about charging entirely.
The build details are aimed at long wear. The headband extends 7cm total (3.5cm per side), the oval earcups are wrapped in breathable protein leather, and the design is meant to spread pressure evenly rather than clamp. It folds down and ships with a travel case. The drivers are 40mm dynamic units with a 20Hz–20,000Hz range, 32 ohm impedance and a stated 40ms latency, over Bluetooth 5.3 with a 10m range. There's a 3.5mm jack, but note the catch: plugging in the cable switches the headphones to wired mode and powers them off, so Bluetooth and ANC stop working. ANC also can't run standalone — the headphones auto-off after 5 minutes without a Bluetooth connection. The color is cream white, weight is 270g, and there's a 1-year warranty.
Buy it if you want one pair of headphones to handle a flight, a train, an open office and a cafe, and you hate charging. Skip it if you want to keep using your own earbuds, or if you plan to listen wired most of the time, because wired mode strips out every smart feature.
• Best for maximum noise reduction → Hmusic MS04. Up to 40dB hybrid ANC with four mics versus up to 24dB on the Relay's earbuds.
• Best for battery life → Hmusic MS04. Up to 80 hours (50 with ANC), and a 30-minute charge is rated for 20 hours.
• Best if you already own Bluetooth earbuds → Avantree Relay & Clan. It turns them into a wireless system for any AUX source.
• Best for airplane seatback audio → Avantree Relay & Clan. The dual 3.5mm adapter covers either connector type; the MS04's own wired mode kills ANC and Bluetooth.
• Best low-latency movie and TV audio → Avantree Relay & Clan. aptX-Adaptive support with a low-latency transmission path is built for that job.
• Best for all-day comfort on a long trip → Hmusic MS04. Adjustable headband, protein-leather over-ear cushions, foldable with a travel case.
• Best for staying aware of announcements → both. The Relay's earbuds have Ambient Mode; the MS04 has Transparency Mode.
• Best for packing light → Avantree Relay & Clan. A small transmitter and a charging case beat a 270g over-ear pair in a bag.
In my opinion, the Hmusic MS04 is the better buy for most people, because it does the whole job alone: strong 40dB-class ANC, 80-hour battery, comfortable over-ear fit and a travel case. The Avantree Relay & Clan only wins if you're already committed to your own earbuds and mainly need to feed them airplane and TV audio — for that narrow job it's excellent, and the dual 3.5mm adapter plus aptX-Adaptive support make it a smart travel tool. If you're starting from nothing, I'd take the MS04. Check the current price on Amazon before deciding.
For raw quiet, yes — its hybrid ANC is rated up to 40dB versus up to 24dB on the Relay's earbuds. But if you want to watch seatback entertainment with your own earbuds, the Relay's dual 3.5mm adapter and transmitter design are the more practical pick.
Charging isn't restricted by the specs. Wired is the limitation: plugging in the 3.5mm cable switches to wired mode, powers the headphones off, and disables Bluetooth, ANC and the buttons. ANC also can't run without a Bluetooth connection — the headphones auto-off after 5 minutes disconnected.
Hmusic MS04 by a wide margin: up to 80 hours of playback, or 50 with ANC on, with a 30-minute charge rated at 20 hours. The Avantree Relay & Clan is a compact kit whose battery levels you monitor on the case display, so it's built for shorter sessions rather than marathon listening.
That depends on what you already own. If you have Bluetooth earbuds you love, the Relay adds wireless audio to planes, TVs and gym equipment for very little bulk. If you need a complete headphone, the MS04 gives you ANC, 80-hour battery and over-ear comfort in one purchase. Check the current price on Amazon for both before you commit.
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