Soundcore C40i review: More comfort, less battery – a fair trade?

In recent years, open-ear headphones have become quite popular among athletes. I’m definitely on board with the concept, as I think these headphones provide much better audio quality than bone-conduction models often used by runners and cyclists.

The Bose Ultra Open is currently my favourite running headphones. They aren’t designed specifically for sports but work perfectly for exercise. One downside of the Ultra Open is that it’s quite expensive, which might deter athletes on a budget from trying them out.

Enter the Soundcore C40i. Sporting a similar open-ear design, the C40i costs a third as much as the Bose Ultra Open and has a decent sound profile, physical control buttons, dual connectivity and more.

It’s by no means the perfect pair of running headphones, but it offers a lot of bang for your buck and is well worth considering if you’re on a budget. Read my full review below to find out if the Soundcore C40i should be your next running headphone purchase (or not).

Soundcore C40i review

Price and availability

The Soundcore C40i was launched in October 2024 and is available to buy now at Anker US, Anker UK and Anker AU for a recommended price of $99/ £99/ AU$149.99. It’s also available at third-party retailers such as Amazon. It comes in one colour, Graphite Grey.

The buds are more expensive than the Soundcore C30i, its predecessor, which sells for $69.99/ £59.99/ AU$99.99. More interestingly, the C30i comes in two colours, Clarity Black and Radiant White.

Specifications

• Type: Bluetooth open-ear true wireless
• Battery life: up to 7 hours, additional 14 hours in charging case
• ANC: No
• Weight (per bud): 5.4g
• Connectivity: Bluetooth 5.4
• Bluetooth range: 10 metres
• Weather resistance: IPX4

Design and build quality

The Soundcore C40i has an open-ear design and clips onto the ear rather than sitting in the ear canal (e.g., Sennheiser Momentum Sport) or resting on top of the ears (e.g., Beats Solo 4). This allows much better airflow in the ears, making the buds more comfortable to wear over long periods.

The U-shaped design is made up of three parts. The part that sits over the ear canal houses the 12 x 17 mm ‘racetrack’ driver. I believe it’s called ‘racetrack’ because of its oblong shape and the little rim surrounding the titanium-coated diaphragm.

The other end of the buds contains the control unit with the physical push button. The tiny microphones, which help reduce noise during calls, are also located here. One of the key upgrades over the C30i is making these mics AI-powered to enhance call quality. I’ll discuss call quality in the section below.

Connecting the two is a thin bridge that houses a memory titanium wire. According to the brand, this can withstand 10,000 bends to ensure longevity. The addition of the titanium wire is the most significant improvement over its predecessor, which was criticised for its lack of flexibility.

The company included two pairs of silicone ear grips in the box for those who find the buds too loose. For me, it shows that the shape of the buds could be improved to mimic the Bose Ultra Open more. Those buds unfurl, so to speak, which provides a more secure fit no matter the ear shape.

The Soundcore C40i weighs only 5.4 grams (per bud), which makes them lighter than Bose’s Ultra Opens, which come in at 7g per bud. The charging case weighs 52g and, in my opinion, feels a bit bulky. I wonder if it would be easier to store the buds sideways in the case, making the overall design slimmer and, therefore, better suited to carry in a pocket.

Audio performance

Soundcore didn’t significantly change the sound of the C40i. The buds have the same-size driver, and the AI assist is only for calls, so expect a similar listening experience to the C30i. This isn’t negative news, though; the C40i sounds good.

They deliver a balanced audio profile, with clear midrange and high-frequency reproduction, though their open-ear design results in a less pronounced bass response compared to in-ear models.

That’s despite the effort to position the buds towards the ear canal to reduce sound leakage. The truth is that open-ear buds will always let more ambient sound due to their design, which means they sound quieter. Plus, the lack of passive isolation compromises the sound, too.

It goes without saying that this isn’t an issue specifically with the C40i – all open-ear buds suffer from this. The C40i does sound decent, though, even with these limitations.

Call quality received a bit of an AI boost. The new algorithm is said to filter out noises more effectively. Interestingly, the microphones are located on the back of the buds. I find it counterintuitive to pick up your voice, although the placement there works for filtering noise.

Call quality is okay, but nothing to write home about. Your voice sounds a bit distant, and the ambient caller sound is muted too much, making me feel like the other person hung up on me during calls. You want to allow a bit of static to come through to know the call is still live.

It’s possible that the open-ear design muffles the static/background noise; I’m not sure. Considering how much the brand talks about call quality in the marketing material, I wasn’t blown away by it.

Battery life and charging

The Soundcore C40i has a 70 mAh battery, providing a 7-hour battery life. Leaving them in the charging case between uses adds another 14 hours to the total combined battery life of 21 hours. There is no ANC, so unless you use the buds at maximum volume all the time, you can expect the C40i to last approximately as long as it says on the box.

The headphones have a quick charge function – 10 minutes on the charge gives you two hours of listening time. It takes around an hour to charge buds from 0 to 100 per cent, while the charging case’s 460 mAh battery requires a little over two hours to fully replenish.

Strangely, the C30i has a longer battery life; significantly longer, in fact. The buds can go for up to 10 hours, with the case adding another 20 hours. More interestingly, a quick charge adds three hours to the battery life, not two. Considering the C40i uses the same driver, not sure where the battery life goes on the new iteration.

Verdict

The Soundcore C40i offers a solid open-ear listening experience with a balanced sound profile, good battery life, and enhanced comfort thanks to its flexible titanium design. However, the improvements over the C30i are minimal, and the higher price may not justify the upgrade for everyone.

While it’s a good option for budget-conscious athletes seeking open-ear headphones, those prioritising battery life or seeking maximum value might still prefer the previous model. For newcomers to open-ear designs, though, the C40i remains a worthy contender.

A small note on the star rating: I would give the C40i 3.5 stars if we did half stars on T3, but alas, we don’t. And giving it the same number of stars as my colleague Mike did to the Bose Ultra Open feels unfair to the Bose. So, three stars it is.

Also consider

Shokz OpenRun Pro 2: Shokz’s bone-conduction headphones offer a truly open-ear design with better situational awareness and comfort for outdoor activities. While they cost more than the C40i, they excel in durability and fit for running and cycling, though they lack the same audio clarity in midrange and bass.

Bose Ultra Open Earbuds: Similar in design to the Soundcore C40i, the Bose Ultra Open Earbuds provide better sound quality and a more secure fit for sports activities. However, they are significantly pricier, making them a premium alternative for those prioritising sound and brand reputation over cost.

Anker Soundcore Life P3: Another Soundcore model, the Life P3 offers better sound isolation, ANC, and a customisable sound profile at a similar price to the C40i. However, they don’t have the open-ear design, which some athletes might prefer for safety during outdoor activities.