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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
If you want an open-ear design that keeps you aware of traffic, voices and everything around you while you train outdoors, choose Purity Air Open Ear; if you need active noise cancellation and a full day of listening from a pocketable, recycled-plastic case, choose Sudio A3. Those two sentences decide most of this comparison. One is built to let the world in. The other is built to shut it out.
• Purity Air Open Ear — biggest strength: open-ear air conduction with 15mm drivers, so audio reaches you without sealing off your ears, plus IPX5 sweat resistance for outdoor workouts.
• Purity Air Open Ear — biggest trade-off: no noise cancellation at all (noise control is listed as "None") and around 6 hours of battery life per charge, so it is a situational headphone rather than an all-day one.
• Sudio A3 — biggest strength: 18dB active noise cancellation, up to 25 hours of total playtime with the case, Bluetooth 5.4 multipoint and a design made from 20% recycled plastics.
• Sudio A3 — biggest trade-off: it seals your ears completely, so you lose all situational awareness, and the sweat/splash rating (IPX4) is a step below what heavy outdoor training usually calls for.
• Who each is for: Purity Air Open Ear for runners, cyclists and walkers who must hear their surroundings; Sudio A3 for commuters, office workers and travellers who want quiet and long listening sessions.
The Purity Air Open Ear is a neckband-style open-ear headphone. You hang it behind your neck, the two speakers rest against the outside of your ears, and you adjust until it sits comfortably. That is the whole idea: nothing goes inside your ear canal. The audio comes through 15mm drivers, which is a large driver for this category, and Purity pairs that with a 20Hz–20,000Hz frequency range and 18-ohm impedance. The brand's positioning is "clear, natural sound" without blocking your ears, and the design backs that up — open ear placement is the entire architecture here, not an add-on mode.
Where it earns its place is movement. IPX5 water resistance handles sweat and light rain, and the neckband format means the headphone stays put through running, cycling or gym work without you fiddling with it. The deliberately open fit also means you hear cars, other cyclists and people around you — which, in my opinion, is the single most important feature for anyone training on roads or shared paths. Dual microphones with environmental noise cancellation handle calls, and Purity's own wording is that they cancel ambient background noise while protecting your voice. Bluetooth 5.3 and a 10-meter range cover normal phone-to-headphone distances.
Sudio A3: Who It's For
The Sudio A3 is the opposite philosophy. These are in-ear earbuds with active noise cancellation rated at 18dB — enough to take the edge off engine drone, office chatter and train noise without pretending to be a full over-ear canceller. They sit inside your ear, seal it, and that seal is what makes the ANC work. The driver is a balanced armature type with 32-ohm impedance, a design commonly chosen for clarity in the midrange and vocals rather than for a booming low end.
Battery is the headline number: up to 25 hours total, made up of 5 hours per charge plus extra from the case. That is a genuine all-day-and-then-some figure for commuting, working and travelling, and the case is described as compact and pebble-shaped. Sudio also gives you Bluetooth 5.4 with multipoint, meaning you can stay connected to two devices at once — phone and laptop, say — and switch between them. If you take calls at a desk and then walk out with the same earbuds, that is a meaningful convenience. The built-in enhanced microphones are positioned for voice clarity in noisy environments, and the whole thing is made from 20% recycled plastics with a Scandinavian-inspired frosted finish and geometric stems.
The trade-offs: in-ear means you are sealed off from the world, so these are a poor choice for road running or cycling where you need to hear traffic. IPX4 covers sweat and splashes but is not built for heavy, sustained outdoor exposure. And the design gives you no way to "open up" and let the environment in when you want to — it is one mode, all the time. Buy it if you want noise cancelling on commutes, long battery life, multipoint switching between devices, and a case you can drop in a jacket pocket. Skip it if you need situational awareness while training outdoors or you dislike the feeling of sealed ear canals.
Side-by-Side: Which Should You Choose?
• Best for situational awareness → Purity Air Open Ear. Open-ear air conduction means traffic, voices and warning sounds come through.
• Best for noise cancellation → Sudio A3. 18dB of active noise cancellation versus none on the Purity.
• Best for outdoor training → Purity Air Open Ear. IPX5 sweat resistance and a secure neckband fit beat IPX4 in-ear buds for running and cycling.
• Best for commuting and office work → Sudio A3. ANC plus multipoint Bluetooth 5.4 is a commuter's toolkit; the Purity has neither.
• Best for calls in noisy places → Sudio A3. Enhanced microphones built for voice clarity in noise, against the Purity's dual-mic ambient cancellation.
• Best for people who dislike things in their ears → Purity Air Open Ear. Nothing enters the ear canal, which also makes it easier to wear for long stretches.
• Best for sustainability-minded buyers → Sudio A3. Made from 20% recycled plastics; the Purity sheet makes no such claim.
If I had to pick one, I would buy the Sudio A3 — but only because my own listening is mostly commuting, working and travelling, and the combination of 18dB ANC, up to 25 hours of playtime and Bluetooth 5.4 multipoint covers more of my day than an open-ear design could. It is the more versatile headphone for general use. That said, if your priority is running, cycling or walking outdoors and staying aware of what is around you, I would choose the Purity Air Open Ear instead, and I would not hesitate — there is no substitute for hearing the road. In my opinion these two are not really competitors so much as answers to two different questions. Before you decide, check the current price on Amazon for both, because the value calculation is the one thing this comparison deliberately leaves to you.
Yes, in my opinion. The Purity is open-ear with IPX5 sweat resistance, so you hear traffic and it survives sweat. The Sudio A3 is in-ear with IPX4, which seals you off from your surroundings during outdoor runs.
Correct. The Sudio A3 lists active noise cancellation at 18dB. The Purity Air Open Ear lists noise control as "None" — its dual microphones handle call noise, not listening noise.
The Sudio A3, by a wide margin. It offers up to 25 hours of total playtime (5 hours per charge plus extra from the case). The Purity Air Open Ear is rated at around 6 hours of battery life.
Yes. The Sudio A3 supports Bluetooth 5.4 multipoint, so you can connect to two devices — such as a phone and a laptop — and switch between them. The Purity Air Open Ear uses Bluetooth 5.3 without multipoint.
I would give that to the Sudio A3, which is built around enhanced microphones for voice clarity in noisy environments. The Purity Air Open Ear counters with dual microphones and environmental noise cancellation, which is a reasonable alternative — but the Sudio's focus on call clarity is the more explicit design goal.
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