The Soundcore C40i open earbuds are a fantastic choice for anyone looking to give open-ear a try for the first time, or for returning enthusiasts looking to upgrade the soundtrack for their next workout.
These buds are open-ear, meaning they sit just outside of your ear instead of within it. This allows you to better hear your surroundings when, for example, exercising outdoors, and is also a great solution for those who dislike the sensation of in-ear buds.
The C40i buds attach firmly around your ear using a reinforced joint, which will be undisturbed by running impact or from high intensity gym machines. These buds fit like a dream — so much so that I sometimes forget I am wearing them, making them easily some of the best cheap running headphones.
Far from sacrificing quality for comfort, the C40i open earbuds offer great sound, especially for an open-ear pair. A nifty mobile app allows you to adjust sound profiles on the go, as well as customize the functionality of the tactile button on each bud.
These are one of the best pairs of open earbuds that you can get for under $100, and are a great purchase for anyone looking for a reliable and great sounding set of fitness buds.
Read on for my full Soundcore C40i earbud review.
Soundcore C40i review: Cheat Sheet
- What is it? A pair of open-ear earbuds
- Who is it for? Runners and fitness enthusiasts, or those who don’t like the sensation of in-ear buds
- What does it cost? At $99, these buds are on the pricier end of Soundcore’s lineup, but this a fantastic price for open earbuds of this quality
- What do we like? The sound quality and comfort is exactly what I want from a pair of workout earbuds, and they don’t budge during high intensity exercise
- What don’t we like? I’m not fully sold on the angle of the speaker, and more variety in colors would've been a nice extra
Soundcore C40i review: Price and Availability
You can pick up a pair of the Soundcore C40i earbuds for $99, or £99, from the Soundcore website. At this price, they are much cheaper than a lot of their biggest competitors — they compare fairly well in quality to the Bose Ultra Open earbuds, for instance, which retail for a massive $249, or the OpenRock X buds that will set you back $179.
Soundcore also offers the C30i open earbuds, which feature a similar design albeit with 3 extra hours of battery per charge, a slightly worse microphone, and non-flexible joint. In our Soundcore C30i review, we also noted a few software issues with connectivity and poor spatial audio. The C40i buds iron out the issues with the C30i, justifying the $40 extra spend.
The C40i earbuds are only available in Graphite Black, which have the benefit of not standing out too much, although I would have preferred more variety in color options similar to Soundcore’s Liberty 4 Pro earbuds.
Soundcore C40i review: Design
- Minimalistic and subtle design
- Durable titanium joint
- Simple but rugged case
The buds have a minimalist design, with a single tactile button for controls. And while they only come in a graphite colour, I find this gives them a sleek, sporty appearance, which I really like. They’re by no means as flashy as the Bose Ultra Open Earbuds, but I prefer the subtlety of the C40i buds.
The connection between the front and back pieces is wrapped in a flexible plastic which is as pliable and grippy as rubber. The internal material of the connecting piece is sturdy titanium, so it’ll stand up to heavy use, but allows more than enough flexibility for everyday adjustments.
The case looks fantastic in graphite and is beautifully constructed, with a firm lid that keeps the earbuds secure. The metallic finish gives peace of mind that the earbuds won’t be damaged while being jolted around in my sports bag.
Although the case is a little too big for your pocket, to account for the oddly-shaped size of the earbuds, it won’t take up much space in your bag. A small LED light at the front of the case acts as a power indicator, and there is a small button underneath the case for resetting the buds — both help make the case simple to use and understand.
Soundcore C40i review: Controls
- One button per earbud allows for precise controls
- You can customize them using the mobile app
The open-ear design of the C40i buds might look unusual at first glance, but have no fear: they’re easy to get your head around. The earbuds feature a physical button, replacing the touch-sensitive controls of the C30i. I’ve never been a big fan of touch controls on earbuds, as the slightest nudge or adjustment is enough to unintentionally pause my music.
The control buttons are located on the back of each earbud. This means you won’t knock the button while adjusting the buds, nor will you be pressing the buds uncomfortably into your ear to use the button, which requires only a small amount of force to trigger.
Clicking the button allows you to pause and skip tracks, and holding it down allows you to raise and lower the volume. After a long time of using earbuds with little to no feedback for these actions, I loved the tactile click of the button, which affirms what you’ve done to help you avoid incorrect inputs.
You can also adjust each earbud’s individual controls using the Soundcore app on Android and iOS devices. I’m a big fan of this and made a double tap of the right bud activate my virtual assistant. Controls for calls are unfortunately not able to be changed, although this is a fairly common limitation.
Soundcore C40i review: Comfort
- Very comfortable
- Stay on your ears
- Extra grip sets to tailor fit
The C40i buds ‘clip’ onto the outer ear, with the front and back units pressing together gently to restrict movement. It's an extremely comfortable experience, and will be a great choice if you experience discomfort when wearing in-ear buds or over-ear hooks. I could hardly feel the C40i buds, and they remained firmly attached to my ear whether I was walking or running.
Unlike the C30is, the C40i buds come with two sizes of transparent grips for the back piece of the earbuds, allowing you to tailor the fit if you need the buds looser or tighter. Each earbud weighs just 5.8 grams, or 0.2 ounces, which is hardly noticeable and doesn’t cause any strain on the ears.
Soundcore C40i review: Audio quality
- Great overall sound quality considering the speaker format
- Clear highs, wide ranging mids and great bass
- Elevated further by the app options, such as 3D audio
After hearing about the sacrifices in sound quality that open earbuds usually bring, I was ready for the worst with the C40i buds — so imagine my shock when the sound was on par with some of my favorite earbuds. Sure, the distance between my ear and the speaker definitely made a difference to the overall quality of the sound, but they held up remarkably well for a variety of tracks.
Training to the best new workout music sounded great on the C40i earbuds. “Get Innocuous!” by LCD Soundsystem had a wealth of detail across the soundstage. Everything was well balanced and the beat didn’t drown out the rest of the song, but there was still plenty of punch.
I was really surprised by just how well the speakers were able to carry bass to my ear, despite the distance between the speaker and ear. If you’re after more bass, the app also comes with a dedicated bass boost mode — although generally I found this isn’t needed.
The same can be said for tracks that earbuds often struggle with, such as the heavy “365 featuring shygirl” by Charli xcx. None of the noise is left behind between the speaker and my ear, and the distorted layers of the song all remain in one piece, thanks in large part to the titanium 12 x 17mm drivers.
While the default settings were good, the earbuds were really elevated by switching on the 3D surround sound feature in the companion app. This is always something I avoid on headphones, as it can lead to the sound becoming muddy, but it gave my music a big boost. Moving away from electronic music, indie rock like Car Seat Headrest’s “Boxing Day” sounded amazing with this setting turned on, with plenty of depth.
Soundcore C40i review: Sound leakage
- Affects all open-ear earbuds, no different here
- The outward facing speaker makes this very prominent
It would be amiss to not mention the obvious issue with the open-ear design. The speaker unit is not nestled within the ear, so there’s a lot of sound leakage. Soundcore claims in their marketing that the internal speaker angle minimizes leakage while directing the sound into your ear canal.
This is half-true in as far as the sound is remarkably clear and rich sounding, although your music will be broadcast to everyone in your vicinity. This is just something to be aware of if this is your first pair of open-ear buds.
If you want to wear your buds on public transport or in the office, it could become problematic, and we’d recommend in-ear buds like the AirPods Pro 2, which are sweat resistant and have a transparency mode for you to hear your surroundings.
Soundcore C40i review: Battery
- Slightly weak battery life versus other open earbuds
- But battery comparable to ANC earbuds
You can expect a maximum of seven hours battery life from the C40i earbuds — quite low considering they are not ANC buds. As I mentioned earlier, the C30i has a comparative battery life of 10 hours per full charge, which I would have liked to see on the more expensive model. Other open earbuds achieve even longer battery life, with the OpenRock X buds lasting for 12 hours. This also sits below most bone conduction running headphones, which generally provide longer battery life. One of our favorite pairs, the Shokz OpenRun Pro 2 ($179) offers 12 hours of battery life, for example.
For most people, though, seven hours should still be plenty of charge, and this is comparable to many ANC in-ear buds. With the case’s 21 additional hours, I was able to go 2-3 days without recharging. If you regularly use earbuds on long adventures though, such as mountain hikes, 7 hours might not be enough.
Should you buy the Soundcore C40i?
It’s safe to say that I was shocked by the C40i buds, which show that you don’t have to spend big to get a competent pair of open earbuds. With the nearest rival in sound and build quality being the expensive Bose Ultra Open earbuds, the C40i buds are a great shout if you want decent quality, sound and comfort but can’t stretch beyond $100.
We found that the C30i buds were a tempting budget alternative, especially compared to premium branded earbuds like the Bose Ultra earbuds but ultimately fell short in a number of design aspects. The C40i buds excel in every aspect that the C30i fell behind, and are very impressive for a budget pair.
Soundcore has avoided many of the problems that plague other open-ear buds, namely a high-asking price and sub-par sound, giving you a great reason to give open-ear buds a chance if you have been avoiding them thus far. The C40i buds will deliver no matter your workout playlist, and will certainly be my gym buddies for the foreseeable future.
