We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-10-03 · 6 min read · Independent comparison
If you want aptX Adaptive earbuds tuned for music and calls with a familiar, well-supported feature set, choose Amazon Renewed Sennheiser CX Plus; if you need aptX Adaptive earbuds built around low-latency, Auracast sharing and a genuinely huge battery rating, choose Avantalk Infinity.
• Amazon Renewed Sennheiser CX Plus — biggest strength: Sennheiser's TrueResponse dynamic driver plus AAC, aptX, aptX Adaptive and SBC codec support, wrapped in a compact in-ear design with ANC, Transparent Hearing and app-based Bass Boost.
• Amazon Renewed Sennheiser CX Plus — biggest trade-off: It is a Renewed unit with a 90-day limited warranty, and it carries no wireless charging, no Auracast and no semi-open option.
• Avantalk Infinity — biggest strength: Two pairs of earbuds in one case (an ANC pair and a semi-open pair), Bluetooth 5.3 with LC3 and aptX Adaptive, Auracast broadcast support and up to 48 hours of playtime with the case.
• Avantalk Infinity — biggest trade-off: Auracast and LE Audio benefits depend on a compatible phone or an Auracast transmitter, and latency-focused features matter most if you actually watch TV or game on them.
• Who each pick is for: Amazon Renewed Sennheiser CX Plus for the buyer who wants one well-rounded, music-first pair; Avantalk Infinity for the buyer who wants flexibility, sharing and marathon battery life.
This is the simpler, more conventional product of the two, and I mean that as a compliment. You get a single pair of in-ear earbuds driven by Sennheiser's TrueResponse transducer — a dynamic driver — with support for AAC, aptX, aptX Adaptive and SBC. That codec list is the reason this pair belongs in an aptX Adaptive conversation at all: on a source that supports it, aptX Adaptive is the codec you'll want for a balance of sound quality and connection stability, and the CX Plus can take advantage of it.
The feature set is built for everyday personal listening. Active Noise Cancellation handles the drone of a commute, and Transparent Hearing flips you back to the outside world without pulling the buds out. Touch controls are customizable through the Sennheiser Smart Control app, which is also where you adjust Bass Boost and pair the buds. Battery is rated at 8 hours in the earbuds and up to 24 hours total with the case. Four ear adapter sizes (XS/S/M/L) are in the box, which matters more than people expect — a good seal is what makes both the fit and the noise cancellation actually work. IPX4 means sweat and light rain are not an issue.
Buy this one if you want a compact, music-first pair that plays nicely with a wide range of Bluetooth codecs and you're comfortable with Sennheiser's app. Skip it if you need Auracast, a second pair to share, semi-open comfort, or a long warranty — this is a Renewed unit backed by a 90-day limited warranty, and it does not do any of those things.
The Infinity is the more unusual product, and the reason is the box. You get two pairs of earbuds in a single case: an ANC pair ("Infinity NC") and a semi-open pair ("Infinity SO"). One case, two very different listening experiences — closed and quiet, or open and aware. That alone makes it a different kind of purchase than a standard single-pair set.
The tech list is forward-looking. Bluetooth 5.3 with LC3 and aptX Adaptive covers both classic Bluetooth and the newer LE Audio side, and Auracast broadcast support means you can join or start one-to-many audio streams where a compatible source exists. Practically, that's a shared-TV scenario, a public broadcast, or handing audio to two people at once. Latency is the other headline: with LC3 and aptX Adaptive, lip-sync for TV, movies and gaming is the use case Avantalk is clearly aiming at. The app handles EQ, firmware updates and finding nearby Auracast streams.
Battery is the standout number: up to 48 hours of playtime with the case, with a 2-hour charge time. ANC and Transparency are both on board, the driver is dynamic, impedance is 32 ohm, and the enclosure is ABS. Warranty is 24 months, with product registration covering the first 12 months of return shipping, plus chat, email, phone, video tutorial and FAQ support.
Buy this one if you share audio, watch a lot of TV or game on Bluetooth, want one pair noise-cancelling and one pair semi-open, or simply hate charging. Skip it if you only ever want one pair of earbuds and don't care about Auracast — you'd be paying for capability you won't use.
• Best for pure music listening and a familiar app ecosystem → Amazon Renewed Sennheiser CX Plus. TrueResponse driver, wide codec support, Bass Boost and customizable touch controls.
• Best for battery life → Avantalk Infinity. Up to 48 hours with the case versus up to 24 hours on the CX Plus.
• Best for watching TV or gaming over Bluetooth → Avantalk Infinity. LC3 and aptX Adaptive are there specifically for low-latency, lip-synced audio.
• Best for sharing audio with someone else → Avantalk Infinity. Two pairs in one case, plus Auracast broadcast support.
• Best for fit and noise isolation in a single pair → Amazon Renewed Sennheiser CX Plus. Four ear adapter sizes and a closed in-ear design that ANC can actually work with.
• Best for warranty peace of mind → Avantalk Infinity. 24 months versus a 90-day limited warranty on the Renewed Sennheiser.
• Best for future-proofing → Avantalk Infinity. Auracast, LE Audio and Bluetooth 5.3 point further ahead than a codec-focused classic pair.
• Best if you want one pair and nothing more → Amazon Renewed Sennheiser CX Plus. Less to manage, less to charge, fewer compatibility caveats.
My Verdict
what is aptx adaptive headphones
aptX Adaptive is a Bluetooth audio codec that adapts its bitrate to the connection and the content, aiming to balance sound quality with stability and low latency. Both earbuds here support it, so both can take advantage of it on a compatible phone or transmitter. On the Avantalk Infinity it's paired with LC3 for low-latency TV and gaming, while on the CX Plus it sits alongside AAC, aptX and SBC.
Yes. Auracast requires a supported phone or an Auracast transmitter — the Infinity works with Avantree Auracast devices and third-party broadcast sources. If your phone supports Auracast, you can use both pairs at once; otherwise you'll need a transmitter to share audio. The earbuds still work normally over classic Bluetooth without any of that.
It's a Renewed unit, and the data sheet lists a 90-day limited warranty rather than a full-length one. The hardware specs are the standard CX Plus ones: TrueResponse driver, AAC/aptX/aptX Adaptive/SBC, ANC with Transparent Hearing, IPX4 and up to 24 hours with the case. If warranty length matters to you, factor that in.
Avantalk rates it at up to 48 hours of playtime with the case, with a 2-hour charge time. Remember that's the combined figure for earbuds plus case, not a single charge. The Sennheiser CX Plus is rated up to 24 hours total, so the Infinity roughly doubles the rated endurance.
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