Sennheiser Consumer Audio CX 400BT True Wireless Earbuds - Bluetooth In-Ear Headphones for Music and Calls - with Noise Cancellation and Customizable Touch Controls, White

Of all the audio upgrades I have bought in my life, these earphones were the best $100 I have ever spent. There are only two things I wish were improved or included. First is the battery life. They will realistically give 5-6 hours per charge in real world use. This is from full charge to the devices shutting off from low battery. They charge quickly in the case or even faster with the case plugged in. Still, longer battery life would be welcome. The second is the lack of Adptx HD codec. They only support AAC, SBC, and Adptx LL. The audio quality of these earphones warrants the best codecs and I'm surprised that was not included. With that said, there is little to fault in the sound quality. When I first put them in and paired them, they presented the worse sound I have ever heard from earphones. Even airplane throwaways sounded better. Then I remembered reading another comment about the same thing and stating they needed to be broken in. Being familiar with high end audio I figured I would break them in for two charge cycled. I parked them with my phone and streamed Tidal until they went dead, charged up and repeated. When I charged them up and put them on. I was presented some of the best audio I had ever heard from an earphone. The sound was incredibly detailed, accurate but slightly heavy in the high end. Bass sounded thin but very accurate. This turned out to not be the case. I opened the Sennheiser app and reduced the high end by 3db. That was just what was needed and they smoothed out and sounded very detailed but not hard it edgy like before. As for the bass, I did nothing but listen to several tracks I was extremely familiar with. When the track calls for bass it is there. Tight, controlled, not boomy or elevated as most headsets are, and very deep. In other words they deliver what is in the recording, not equalized to sound bass heavy. The more I listened, the more I heard what an incredible sounding ear buds these are. I did not want ANC. I feel it has its place in certain applications like travel, but I only have these to listen to music. The isolation is very good and minimal ambient noise gets in. Even outside or walking with traffic they seal very well. I hear more audio artifacts from noise canceling that bother me than a little bit of ambient noise. After all, if listening to speakers you hear everything anyway, even in a quiet living room. These are worn often, sometimes 12-13 a day. Phone calls sound amazing and while the mics are not the most noise canceling for cell calls out there, I have only heard a few people afk if I was outside when there was string winds. But all say voice quality is excellent. To get any better audio quality many times more money has to be spent and even in the $400-$500 range I have heard nothing that that is any better sounding. Better than Bose, WAY better than air-pods. This is based on audio quality only. If you MUST have ANC or longer battery life for some reason these will not work for you. If you are looking for unbeatable sound,there is nothing close to these without getting into the over $750 range and up. For $100, these are the audiophile bargain of the year. Will not be sorry if you purchase these.

Sound quality The sound on these things are phenomenal. Even more so for earbuds at this price range. But hey, its Sennheiser. Also, by using the Sennheiser Smart Control app, you can really make these sound how you want. From high bass, to low treble you can really change a lot. It also has the codecs for many different devices so it will sound great on Apple AND Android devices. Mic is decent and never had any problems with people understanding me even on windy high speed bike rides. Touch controls are great and responsive. Just try not to hit them when scratching your ears! One thing to not is that the right earbud MUST be out for use while the left one can be put back in the case. Build Quality: While the case could feel cheap at times as it just made from plastic, its clear to see that money went into the earbuds. They are very well built and fit great for me. While I don't have the largest ears, I found that the normal size worked the bets. They also come with Small, and large size caps. I also recommend twisting the earbuds inwards for a tighter feel. They have stood in during runs, windy bike rides, and vehicles. Battery: Batter is great. I think it gets about 20 hours with he case. You can check battery by pressing the little button on the back. green for high, yellow medium, and red for critical meaning you need to charge very soon. I think you can get about 4 charges with the case but I've had these for about a month now and I've only had to charge these things about 4 or 5 times and I use them for hours! Also. charger uses USB C Problems: While I think these earbuds are incredible, I do have some things I think they could add. Given the price range, I think earbuds like these should have some form of a transparency mode. While I think they have the hardware for it, the software does not support it. Honestly, This is the only area I'd say these things were "lacking". Active noise cancelation would be very nice too for the price but sadly, it is not included. It does have passive noise cancelling and honestly, I don't know the difference. Overall: Overall? Awesome product. These things sound nothing short of incredible and they fit and are built very well. They allow for great customization of buttons and EQ. About as easy to put on as any other earbuds. If you are looking for high quality earbuds, these are it.

I'll be comparing three different pairs of headphones, as any one of them would have top marks by themselves, and my review would be meaningless; With this price point they had better be decent headphones. The headphones I'll be comparing are: Apple AirPods Pro (referred to as "Air" from here on), Sennheiser CX 400BT (referred to as "CX" from here on), and Sennheiser Momentum True Wireless 2 (referred to as "MO" from here on). Moving on. *Sound* All 3 sound great, but the MO was the clear winner, giving the most true-to-life sound, including all of the subtle highs and lows. The Air was a not-too-far-off second; it lacked some depth in the high notes. The CX wasn’t too far behind the Air; it had better sound, however, it had significant issues stemming from noise cancellation, see below. *Noise Cancellation* The Air definitely has the best noise cancellation, for me; it isn’t especially awesome, but it’s adequate for most situations. It’s probably about as good as you can expect in this price range, but cannot compare to over-ear headphones. The MO wasn’t too terribly far behind, and may even have better noise cancellation, but due to fitment issues, below, the seal wasn’t good enough to cancel out most of the noises around me. The CX has no noise cancellation. I didn’t realize how big of an issue this would be, but when I actually manage a decent seal on the ear buds, I can hear my own breathing (not a mouth-breather, by the way!) almost as loud as my music. This was the deal-killer for me. Otherwise the CX would be on par with the others, and at half the price. *Fitment* Both of the Sennheisers fit identically, and are a better fit, in that they actually stay in my ears. However, as stated above, the actual buds don’t fit my ears; I seem to be right between the small and medium buds. The Sennheisers kind of twist into your ear, and hold similar to a sport headphone, which is nice, but also a nuisance. The Air’s buds are a much better fit, but they don’t stay in my ears at all; The slightest movement and they fall out. I bought some “ear hooks” for them, and they stay in my ears perfectly, now. However, the ear hooks add just a hair of silicone to the exterior of the headphones, which caused me discomfort after a few hours (Note: this has nothing to do with the actual headphones). *Battery* I want to say the Sennheisers’ battery lasted way longer than the Airs (a full work day). That said, I did not pay attention to how long it took them to recharge in their case. The Airs seem to only last 6-8 hours (I should mention I have long work days, haha), but I watched their battery level for a couple minutes the first time I charged them, and they were charging about 1% per 10-15 seconds. Assuming it actually keeps that pace, that’s a full charge within 16-24 minutes, which seems pretty good to me. One charge drained the Air’s case by 20%, so you get 5 charges out of it. Unfortunately, I don’t recall most of this stuff with the Sennheisers. *Technology* I’d say that none of them stand out as being better here, just different. The Sennheisers might have a slight upper hand, as they have more controls available to them, but some of them make no sense to me, and there’s no way to reprogram them (as far as I can tell. It may be possible via their app, but I imagine this is specific to the device, and I want them to work the same on all devices. Also, both Sennheisers have issues with the fact that all controls are right on the face of the headphone, and it’s almost impossible to put them in your ears without touching the face. The Airs CAN’T CONTROL VOLUME! For real?! You have to control it from your phone/listening device. This absolutely drives me nuts (at least 20 times a day). The Airs actually has a button on the stem that you have to push for all of the controls. I was under the impression it felt seamless, similar to a touchscreen; Not the case. Lastly, based on their product description and reviews, it seemed that the Airs can only connect to Apple products, but based on their incredibly short manual, it would appear that it can indeed connect to any bluetooth device (unfortunately all I own are Apple products, so I can’t verify this). All 3 headphones pause your music when you take them out, which is nice. I sure wish I could turn them off (without putting them in their case), but none of them allow this. *Summary* For myself, I opted to return the Sennheisers, and plan to stick with the Air. The Sennheisers had more significant issues involving fit and noise cancellation, and the Air has more significant issues with the interface (no volume control), and don’t stay in your ears without outside assistance via ear hooks.

Summary: Better sound quality than most, cheaper than the top-of-the-line active noise cancelling sets, and consistent connectivity. My background - former recording engineer/musician, so my other set of earphones are quad-driver custom molded in-ears. I'm not expecting that level of quality from a set of $2-300 wireless units, but I don't put up with bad sound quality and I like relatively flat response. I've previously tried the Jabra 75t's and other, less expensive units, couldn't deal with the sound quality and dropouts. I'm not a fan of hugely stilted EQ (the Jabras in particular had bass that was incredibly overpowering in a bad way). ** The good ** - Sound quality is great for a set of $200 earphones. EQ adjustment was minimal to get them in the 'sweet spot' where I could hear everything. Highs and transients could be a bit smoother, but everything is there and you can pull the things you want up/down vs just having to correct for massive problems. Soundstage is impressive for something this small and (relatively) inexpensive. - Connectivity is miles better than I've had before. I used to get dropouts riding my bike on other units (3 foot connection distance), and with these I can walk across the room and there's no issue. Time will tell if this holds for other use cases, but so far so good! - Battery life is solid at 7 hours default, plus more with the case. Longer than I'd ever have them in for in one setting, anyways. - USB C charger. Love USB C and use it for most of my other devices, so this is handy. - The Android/iOS app is great and easy to use. Relatively easy setting it up/getting it connected. ** The not-as good ** - Right ear only for solo stuff - doesn't bother me, and they explicitly tell you this in the instructions, but be aware of it if you're a left-ear only type person. - No ANC - I didn't want active noise cancellation, so up to you if you want it or not. The ANC version the Sennheiser makes is $100 more, so up to you. - Slightly wonky firmware updates that take 45 minutes. Hopefully won't have to do this often, so not a big deal to me. Overall, I'm very happy with these - I'd been waiting to see if they'd release a version cheaper than the Momentum Wireless 2's, and this has answered my request! I'll update this review if anything goes haywire down the road, but so far these seem like a keeper.

Wearing my earbuds when I work out I have had many different pairs that do not last more than a few months. When I purchased these over a year ago I was unsure as I was unfamiliar with the brand but I thought I would give it a go. For the most part, I have been pleasantly surprised. The sound quality is decent, the fitment is good, and the noise canceling is better than in my previous pairs. The controls are a bit touchy and allow too many options regulated by a simple touch or series of touches(I didn't sign up to learn morse code). It is not uncommon in the gym while doing overhead presses that my shoulder bumps one of the earbuds wrong and suddenly my music is off and I'm making an unintended call. Now after just over a year, the left earbud has failed, probably not a bad lifespan based on my experience with previous ones, but thankfully it is covered by the Sennheiser 2-year warranty. Now if I can just get Sennheiser to respond to any one of my multiple requests for a warranty claim made over several weeks... Other than product service, seems like a decent earbud.

These are simply the best earbuds I've ever used and ever owned. Crisp sound, great battery life, nice features on the app, comfortable...they are absolutely outstanding. I've used Apple Airpod Pros, Galaxy Buds Pro, Pro Beats by Apple, Jabra 85t Elites, Sony WH-1000xm4s and other mid to high range earbuds and headsets and the sound produced by these topped them all. I realize its down to personal preference but these were my favorites. They've unfortunately died recently so I'm writing this as a memorial to them. I've used these almost every single day for around 18 months for anywhere from an hour to 10-12 hours a day. I've come to love audiobooks (and have consumed many within a day) thanks to these earbuds. Countless hours of music with Spotify, around 120 books from Audible read since these were purchased...If I were able to count the amount of hours I've used these earbuds since July of 2021, I would say these were worth the investment I spent. There is 0 exageration in my review, I've been addicted to these earbuds and I carry them with me everywhere. CX 400 BT's, You will be missed.

Currently reaching out to them for support because something in my right bud has come loose. I have no sound coming out the right but it still connects and can control. Prior to this problem I was actually loving these. The sound was so good and exactly what I was after. The battery life is a bit meh but to be expected. I loved these and I hope customer service pulls through. Update: submitting for warranty is both wonky and to the point. I expected it to be a bit more involved but it was very simple once you find the correct site. There was zero human communication, which I didn't like. But they immediately sent me a replacement without any problems and super quick, which I loved. Unfortunately the speakers in my new ones need broken-in again to get the butter zone back, but at least they function again! Update again: I cannot recommend these. They sound great (imo) but they fit terribly and they just keep breaking. I had my originals for 6months before the internals broke and I got no sound in a bud. They did replace them, but then those also broke the same way in about the same time. They then replaced them with the true wireless ones... Which just broke in the same way. I expected so much better craftsmanship from Sennheiser. I'm so genuinely sad because I enjoyed the sound of these so much, but I can't possibly allow myself to buy these or any others similar from them.

Let's get the obvious out of the way: these buds are larger than you expect, and heavier, in part due to the 7mm driver (same as the more expensive Momentum line from Sennheiser)... but you won't care about the size or weight, because they just sound so, so incredible. That 7mm driver does make amazing sound, better than any wireless earbud I've tried, and for around $100 at the time of my purchase, this has better "quality sound / dollar" than anything I've tried. But there are some odd design decisions. The touch surface for the control on the outside of the big block is hypersensitive (even a quick touch from my hand can trigger a pause, much more sensitive than, say, Airpods Pro). On the good side, you can control volume from these, but it's a bit tricky due to the sensitivity. For all the audio quality, I found I had to set the volume higher with these than with other earbuds on both iPhone and Windows PC Bluetooth (in Windows, go to Sound in the Control Panel (under "Hardware and Sound"), highlight your headphones, click Properties, and select the Enhancements tab. Check "Loudness Equalization" and hit Apply to turn this on, helps a ton). With the plugs in, your do get good isolation from the outside (so "passive" noise reduction), though of course, you now hear every breath and gurgle from inside your body, as you do with any sealed-ear device. Even with a Bluetooth 5.0 connection (they support up to 5.1) on the PC, BT lag is still present; this is really evident watching videos and, to some extent, on video conferences. The buds stick out from your head, and are heavy, so extended wearing became ear-canal sore, but never really painful. The ear tips are silicone, but less flexible than from other vendors: I usually wear a medium in other earbuds, but it feels a touch large for my ears; the small felt too small. I may invest in Comply Foam for the first time. The buds support SBC, AAC and aptX, which is nice for iOS or Android users. Microphone quality is the usual: it's good enough, but not as good as Airpods Pro, and clearly not the primary focus of the buds. It'll be ok, but expect to have to repeat sometimes, as with almost every wireless earbud out there. Also, I missed the auto-shutoff from so many of the other modern earbuds; these just keep playing when you take them out (luckily, due to the hypersensitive touch panels, I accidentally pause when taking them out most times!). Also, an odd design choice means that the "power pads" where the buds connect to the terminals in the case is just rear of the earplug; this puts a ridged surface directly touching one of the folds of the ear. If you push the earpiece all the way in, you are putting the one rough surface directly against your ear. Sennheiser could have easily put this on, say, the rear-facing portion of the block and let smooth plastic touch the ear, but, well, they didn't. You'll get used to it, but it's just an unnecessary design choice. Connection is quick with verbal feedback in the buds. Battery life is as expected, and runs easily the 6 or so hours; the case can give another 12-13. It takes longer than an Airpod Pro to recharge; it's worth charging over a longer break than just the few minutes other products can charge in. The case has a USB-C plug, but the included cable is tiny; throw a normal length one in your cart when you buy this. The case has no wireless charging ability, oh well. The case is larger than expected, a little heavier than an Airpods Pro case, and due to it's rectangular shape and width, a bit pocket un-friendly. The top does have a hinge-helper which holds the top open, something more cases should try. Sennheiser has an app for iOS and Android, and it really is necessary. It allows a firmware update to 2.13.0 that substantially improved connection speed. You can customize almost all the tap patterns; I added "play pause" to the right ear instead of just on the left. It also lets you store different EQ profiles (just 3 bands, so a bit gross, but better than nothing; there's also a "touch and slide" interface but it's really just a layer on the 3 band). The profiles are stored in the bud, and can be changed live via the app, even if you are listening to another source (so, using the phone to adjust the eq while listening to the computer). The app lets you control the connections as well; like most BT devices, you can't connect to more than 1 source hot at a time (aka no multipoint), and switching is still manual (Apple's Airpods ecosystem is more automatic, and Bose has done a nice job of having 2 sources mounted at once and having easy swapping between them). These are not sport buds: they don't quite stay in all that well (in my ears) when moving and have 0 water/sweat protection beyond the usual (a bit will probably be fine, but during a heavy workout, these re not fully protected from salty sweat.) So, other than odd choices in where to put the power connectors, the large size of the main block, the sensitivity of the touch panel, and oddities of the eartips size, the sound quality is amazing, far better than I expected from a Bluetooth connection, esp. for the price. Master and Dynamic has a similar pair that drop in price to around $100, and Yamaha has a nice pair around this price with similar specs, but after trying them all, I'm willing to put up with the odd design choices for that clean Sennheiser sound.