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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
If you want the lightest, smallest-fitting ANC earbuds in this matchup for small ears, choose Anker Soundcore; if you need real-time translation and the strongest rated noise reduction, choose Anker Soundcore P31i. That's the short answer. The longer answer comes down to what actually annoys you day to day — a bud that slowly works its way loose on a two-hour commute, or a bud that can't handle a call in a foreign city.
• Anker Soundcore (Space A40) — biggest strength: tiny, paper-light shells that Soundcore explicitly says are smaller than all its other ANC earbuds, plus 50 hours total with the case and LDAC Hi-Res support.
• Anker Soundcore (Space A40) — biggest trade-off: Bluetooth 5 and no IP rating listed, so it's the less future-proof and less sweat-friendly of the two.
• Anker Soundcore P31i — biggest strength: adaptive ANC rated to cut noise by up to 52 dB, real-time AI translation across 100+ languages, six mics, IP55, and Bluetooth 6.1.
• Anker Soundcore P31i — biggest trade-off: a heavier, larger case (59 g) and a bud shape that isn't pitched at small ears the way the A40 is.
• Buy the Space A40 if you have small ear canals and want buds that disappear in your ears for long listening sessions.
• Buy the P31i if you travel, take a lot of calls, and want translation and stronger noise cancelling built in.
This is the pair I'd hand to anyone who's given up on earbuds because they keep slipping out. Soundcore's own spec sheet calls the Space A40 smaller than all of its other ANC earbuds and "as light as a sheet of paper," with an ergonomic shape — that's the entire pitch, and it's a good one if you've got narrow ear canals. The rounded-tip silicone design and the sub-1-gram-per-bud feel (in practice, the lightest in this comparison) mean you can wear them through a full workday without that hot, stuffed sensation.
On the features side you get adaptive ANC that detects your surroundings and picks a cancellation level automatically — indoors, outdoors, commuting, flights. Soundcore rates it at up to 98% noise reduction. Battery is a genuine strength: 10 hours per charge, 40 more in the 800 mAh case, 50 total, and a 10-minute top-up buys you 4 hours. That's a commute-week kind of number, not a charge-every-night kind of number. Sound is handled by double-layer diaphragm drivers with LDAC for Hi-Res wireless, and touch controls run through the app.
Who should buy it: small-eared listeners, people who wear buds for hours, commuters who hate charging cables, and anyone who wants Hi-Res audio without a bulky fit.
Who should skip it: you need an IP rating for gym sweat or rain, you want the newest Bluetooth generation, or translation matters to you — the A40 has none of those. Also note the colorway here is purple with a matching purple case, so if you want something neutral, look elsewhere.
The P31i is the more feature-dense earbud, and it's not subtle about it. Adaptive ANC is rated to reduce noise by up to 52 dB — the highest figure in this comparison — and the system re-detects your environment and adjusts on its own. That's a serious number for a true wireless bud, and it's the main reason I'd point a frequent flyer here.
Then there's the headline trick: real-time AI translation across 100+ languages, handled on the fly so conversations stay natural. If you work with international teams, travel for business, or live in a multilingual city, that's a feature you simply cannot get from the Space A40. Call quality gets six AI-enhanced mics with a noise-reduction algorithm plus wind-noise handling, which matters more than people admit — windy-street calls are where most buds fall apart.
Battery is rated 10 hours per charge, 50 total with the case, and 8 hours with ANC on (40 total). A 10-minute charge gives 3.5 hours. Audio is Hi-Res certified with LDAC and an 11 mm dynamic driver, frequency response out to 40 KHz, plus spatial audio. The case is 59 g and measures roughly 5.8 cm square by 29.3 mm tall — compact, but heavier than you'd expect. Build is plastic, rubber and silicone, finished in light blue. Controls are touch-only, with no app listed in the control method — worth knowing if you like deep EQ tinkering. Bluetooth 6.1 and IP55 round it out.
Who should buy it: travelers, call-heavy workers, anyone who wants the strongest rated ANC and translation in one bud, and people who want an IP rating.
Who should skip it: small-eared listeners who prioritize fit above everything, and anyone who prefers app-based control over pure touch gestures.
• Best for small ears → Anker Soundcore (Space A40). Soundcore itself markets it as its smallest ANC earbud, and the rounded-tip silicone shape is built for a snug, low-profile seal.
• Best noise cancelling → Anker Soundcore P31i. Up to 52 dB adaptive ANC versus the A40's up-to-98% reduction claim — the P31i's figure is the more concrete, higher-rated spec.
• Best for calls → Anker Soundcore P31i. Six mics with AI voice separation and wind-noise reduction beats the A40's noise-detecting mic setup for clarity outdoors.
• Best battery flexibility → Anker Soundcore (Space A40). Both hit 50 hours total, but the A40 keeps its full 10-hour single-charge figure regardless, while the P31i drops to 8 hours with ANC on.
• Best for travel and languages → Anker Soundcore P31i. Real-time translation across 100+ languages is unique to it in this pair.
• Best for gym and rain → Anker Soundcore P31i. IP55 is listed; the A40's sheet lists no IP rating.
• Best for future-proofing → Anker Soundcore P31i. Bluetooth 6.1 versus Bluetooth 5.
• Best for app control and EQ → Anker Soundcore (Space A40). Its control method explicitly includes the app; the P31i is touch-only.
• Best for long, all-day wear → Anker Soundcore (Space A40). Lighter shells and an ergonomic small-ear fit win over a longer feature list when you're wearing them for eight hours.
In my opinion, if your problem is that earbuds never fit — that dull ache after an hour, that slow slide out of your ear on the train — buy the Anker Soundcore Space A40. It's the pick I'd make for small ears, and the 50-hour battery plus LDAC Hi-Res sound means you're not sacrificing much to get that fit. But if fit isn't your issue and you want the strongest rated ANC, IP55, Bluetooth 6.1 and live translation, the P31i is the more capable earbud and the one I'd take on a flight. Check the current price on Amazon before deciding, since that gap often settles the argument.
By design, yes. Soundcore states the Space A40 is smaller than all its other ANC earbuds with an ergonomic shape, while the P31i is a standard bud design with no small-ear claim. If fit is your main concern, the A40 is the safer bet.
Yes — it's listed as supporting real-time AI translation in over 100 languages. That's a genuinely different use case from the Space A40, which has no translation feature at all.
The P31i, on paper. It's rated to reduce noise by up to 52 dB with adaptive ANC, while the Space A40 is rated at up to 98% noise reduction. Both adjust automatically to your surroundings; the P31i's spec is the more specific figure.
I'd be cautious. Its data sheet lists no IP rating, while the P31i carries IP55 for dust and water resistance. For sweat and light rain, the P31i is the better choice.
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