We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-09-21 · 6 min read · Independent comparison
If you want a single device that translates 144 languages in real time and doubles as everyday music and call earbuds, choose ANFIER M6; if you need an in-flight adapter that lets two people share one airplane screen on their own Bluetooth headphones, choose Avantree Relay & SoundJet.
• ANFIER M6 — biggest strength: Real-time two-way translation across 144 languages and accents, with offline translation in 11 major languages and no subscription required.
• ANFIER M6 — biggest trade-off: It's a niche tool first and headphones second. If you don't actually need translation, you're paying for capability you'll rarely use, and its battery life (5 hours per charge, 15 with the case) is modest.
• Avantree Relay & SoundJet — biggest strength: It connects two Bluetooth headphones at once to a plane's 3.5mm AUX output, so two travelers can watch the same seatback screen together on their own earbuds.
• Avantree Relay & SoundJet — biggest trade-off: It's a transmitter only. It does not work with TVs, phones, tablets, hearing aids or musical instruments, so its usefulness is almost entirely limited to flights.
• Who each pick is for: Choose ANFIER M6 if language barriers are your daily problem. Choose Avantree Relay & SoundJet if your problem is a long-haul flight and a partner who wants to share the movie.
The ANFIER M6 is built around one idea: put a translator directly in your ear. It handles 144 languages and accents with a claimed 98% accuracy and a 0.5-second response time, which matters because a translation that arrives a beat late breaks the rhythm of a real conversation. The bigger deal for travelers is the offline mode — 11 major languages, including Chinese, English, Japanese, Korean, Russian, German, French, Spanish, Thai, Vietnamese and Arabic, work without Wi-Fi and without a subscription. That last part is the quiet selling point. You buy it once and the translation doesn't become another monthly bill.
Who should buy it? Frequent travelers, businesspeople working across languages, students, and anyone who regularly talks to people who don't share their first language. The in-ear ergonomic shape plus three sizes of silicone tips should suit a wide range of ears, and sound isolation helps in noisy places. Who should skip it? Anyone whose main need is all-day music listening — 5 hours of continuous use per charge and 15 hours total with the case is fine for a workday or a trip segment, but it isn't a marathon battery. And if you never cross a language barrier, the M6 is simply more device than you need.
Avantree Relay & SoundJet: Who It's For
The Avantree Relay & SoundJet R1 solves a very specific, very real annoyance: airplane seatback entertainment that only works through a wired jack. It's a Bluetooth transmitter that plugs into a 3.5mm AUX output and broadcasts audio to your wireless headphones. The standout feature is dual pairing — two Bluetooth headphones or two sets of AirPods can connect at the same time, so couples or travel partners can watch the same in-flight movie side by side without splitting a cheap pair of airline buds.
Audio quality is handled by Qualcomm aptX Adaptive, which is designed to deliver balanced sound and a dependable connection for the length of a flight. Battery life is the other headline: up to 25 hours of playtime on a single charge, which comfortably covers even a long international route with time to spare. Setup is wired on one end (the AUX cable into the seat) and wireless on the other, and it supports Bluetooth-enabled headphones.
Now the honest part. This is a single-purpose tool, and Avantree is upfront about it: it does not work with TVs, hearing aids or musical instruments, and because it's a transmitter only, it won't pair with phones or tablets. That rules out using it at home on your TV or as a general-purpose audio gadget. If you fly a few times a year and already own good Bluetooth headphones, this is a genuinely clever upgrade. If you're a home user looking for a way to send TV audio to your earbuds, this is the wrong product — full stop.
Side-by-Side: Which Should You Choose?
• Best for travel without a signal → ANFIER M6. Offline translation in 11 major languages, no Wi-Fi and no subscription needed.
• Best for battery life → Avantree Relay & SoundJet. Up to 25 hours of playtime versus 5 hours per charge and 15 hours with the case on the M6.
• Best for sharing entertainment with a travel partner → Avantree Relay & SoundJet. Two headphones connected to one airplane seat at the same time.
• Best for everyday music and calls → ANFIER M6. Bluetooth 5.3, Qualcomm chipset, aptX Adaptive Lossless, and hands-free calling in one device.
• Best for reading signs and menus → ANFIER M6. Photo Translation handles text in images.
• Best for home TV or phone audio → neither, with a caveat. The Avantree Relay & SoundJet explicitly doesn't support TVs, phones, tablets or hearing aids, so don't buy it for that.
• Best for a light, versatile travel kit → ANFIER M6. Three functions in one pair of earbuds beats carrying a separate translator.
In my opinion, the ANFIER M6 is the one I'd buy. It covers more of real life: translation when you need it, music and calls when you don't, and it keeps working offline without asking for a subscription. The Avantree Relay & SoundJet is excellent at exactly one job — sharing in-flight audio between two people — and if that's your problem, it's the smarter pick. But for most travelers, a device that speaks 144 languages earns its place in the bag far more often than one that only works on a plane. Check the current price on Amazon before you decide, then match the pick to the problem you actually have.
FAQ
No. It's a Bluetooth transmitter designed for airplane 3.5mm AUX output, and it's not compatible with TVs, phones, tablets, hearing aids or musical instruments. Buy it for flights, not for home audio.
The Avantree Relay & SoundJet, by a wide margin — up to 25 hours on a single charge. The ANFIER M6 gives 5 hours of continuous use and 15 hours total with the charging case, with a 90-minute recharge time.
Yes, in different ways. The Avantree Relay & SoundJet pairs two Bluetooth headphones to one seat, so two people hear the same audio. The ANFIER M6's Free Talk Mode has each person wear one earbud for natural, hands-free two-way translation.
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