I picked these up to have a good pair of IEMs to wear to the gym and ...
938000
I picked these up to have a good pair of IEMs to wear to the gym and at home. I also have a set of Brainwaves ProAlphas and Sennheiser HD280s headphones that I would be comparing the sound to.
Sound:
I've let these break in for a week before comparing them critically to my other IEMs and headphones. After that time the bass is tight, but a hair lacking. The highs are pronounced and detailed, with the mids filling out the rest of the tone. I hope they will relax and get warmer after I've used them more. As with most IEMs, the tips can have a major impact on what you are hearing. The clear silicon tips that came with them worked better for me than the Comply foam tips that I use with my Brainwaves. Where these really shine is the details these IEMs bring out in the music and wide sound stage. When listening to a 24\96 .wav file I can hear a full range from my left to my right, creating an immersive experience.
Construction:
The feel well build. I like the flexible, yet reinforced 1/8" jack arm and cloth covered cable. The covering keeps these IEMs from getting too tangled up, a real problem I have with the Brainwaves. The drivers themselves are light and sleek, although the protection on the cables going up into them is a little on the light side. When wearing them straight down I get some microphonics through the cable, especially when running. This goes away if you wear them over the ear. They don't have an inline control or mic, but I never use any of that, so it doesn't bother me.
Packaging:
The little box HiFiMan ships these in is nice. Older reviews of the RE-400s say they don't come with many tips or a case, but that must have changed. They came with a few different sizes of black or clear silicon tips, an alligator clip, and a case. Simple, yet included everything you need.

Highs- for $50 these are nice sounding IEMs. I really like the sound stage and construction. Very comfortable.
Lows- Right now they are a little sterile. Listeners that want big thunderous bass would be disappointed.
Bottom Line- I really like the details these bring out in my music. I listen to FLACs ripped from CDs or HiDef .wav files that I've purchased, because I enjoy the experience of listening to music. These IEMs do my music justice. I can't say that they will replace my Brainwaves as my go-to for general listening, but they are better at presenting nuances in music.
724350
Good headphones, the sound quality isn't the best but the bass is bumpin which is what you want when you work out. I have small ears so the stabilizer piece hurt and they stay on just fine without it, whether you're lifting or running or doing backflips. Overall I wouldn't have paid the full $130 for them but the sale price of $50 was to good to turn down, definitely worth that price
2250789
I saw these on a musician website the day my Sony MDR-EX85LP broke, so I thought I'd give them a try; I've gone through about 5 Sony ear-buds over about 10 years, but these were cheap enough to see how they were.

The sound is very, very bassy.  I've had to change the EQ on my computer and iPod because of this.  It's almost to the point of muddying up the sound.  I feel like there is some definition lost because of this.  The left side also feels extra bassy.  They are very good at noise cancelling though.

The fit is a bit rough too.  They only come with ONE size of silicon ear fittings; luckily they are the medium size which fit me.  They are very stiff though, so I've already swapped them out for the many I've acquired from my Sony ones.  I don't find myself able to wear them for very long.  I'm an architect and sit for hours listening to music, and my Sony ones have never hurt my ear.  These get painful like the old Apple ear-buds after an hour or two.  The pull from the suction in the ear is also too much.  A plus is they seem to be built sturdily.

I have to say I've already ordered some of my trusty Sony ear-buds, because I can't see myself getting used to these.  They are a good back up when there is downtime between ordering new headphones, but they are not good enough to be my daily players.
2612311
Based on the fact I had a pair of the over ear headphones before I already know these are going to be good.
4242256
I did a bit of research before landing on this pair of headphones, and bought them because of the fit, stability, and sound quality.  I took them out of package wore them for a bike ride with no issues and when disconnecting them from my phone, the wire came loose and detached.  I always take very good care of my electronics, and this was not something that I was putting excessive force on.  Since it's Sony, I don't anticipate that it's a chronic issue with this model, I'm guessing that it was a manufacturing issue for the specific one that I purchased.  Either way, I'm not planning to buy another one of the same model.
1208683
These aren't the best-sounding headphones for my more serious listening, but the sound is plenty good enough for working out in the gym. They're comfortable and they stay in my ear very well, The yo-yo-like cord wrap carrier keeps the cable from tangling up in my pocket or in my gym bag.  And most importantly, my heavy perspiration never seems to bother them -- which is more than I can say for several other brands of headphone that are specifically advertised as being sweat-resistant, which these are not.  The cables are not the strongest, and there are a lot of opportunities to snag them on something while working out, so after six months I wasn't all that surprised that the left channel cable broke... but these are so inexpensive that I really don't care! I bought three more.
3905388
I bought these to go with my phone so I can go to the gym and listen to music while I am running and it worked wonderfully :)
814657
These headphones sound great and are good for the gym. I've been using the same pair for months.
3494904
I'll write a follow-up after using these for a few more weeks, but after only a few days I can say without hesitation that I'm happy with the purchase. The sound isolation is top notch for an IEM (In Ear Monitor), the frequency response is flat without being completely void of low frequencies, and they're surprisingly comfortable for how deeply into the ear canal they're designed to go.

I have owned over a dozen mid to high-quality IEM's (with these being on the upper end of the scale for me), and these sound as good as anything I've tried, but they fit better!

I've already noticed that they've broken-in a bit after about 20-hours or so. The bass is more pronounced (but still tight), and the Mids/Highs are smoothing out. If you take them out of the box and find them lacking bass or a little harsh on the mid/high end, just give them some time... They settle-in nicely with time. I can't wait to hit the 100hr mark and beyond to see how they've improved. More to come...
848838
So I've been on the hunt for some quality earphones that I can use while working out. And by working out I mean long winded workouts on a daily basis. Not the casual here and there workouts that most average reviewers practice.

With that said, I came across a few websites during my search that had these earphones at the top of the list so needless to say I went ahead and purchased them in hopes that I would be a happy customer.

I must note that prior to going on the hunt, I had been using the Monster Livestrong ISport Earphones, which, although not perfect, were far superior to these. But in the end I lost them during a trip recently. They are now discontinued so I am now left to find something new.

So onto the review.

Package was decent enough but nothing special. Earphones come with various sizes of ear inserts that attach to the actual earphones themselves so finding a good fit shouldn't be a problem.

The wiring is a bit flimsy and where it attaches to the actual earphone is somewhat fragile. Although it didn't happen to me in my handful of usages, I can see how over time (not very long at that) the wire could fail from the earphone and either break or lose connection. Most earbuds I've had have a relatively rigid wire at the point where they actually connect to the earphone.

When I put them into my ears It almost felt as if they weren't in all the way. The outer rubber ring is supposedly supposed to secure the earphone to your ear by pushing up against that little bridge of cartilage that runs along the outside of the inner ear. To me, it didn't feel like it was big enough to be pushing up against my outer ear. But during my run during an actual run it miraculously stayed in little to no adjustment required during the entire 3 miles that I ran. And it also felt pretty non existent as others reviews have stated. So in terms of comfort, I definitely give it props as it not only stays put during rigorous activites but it also almost feels like it's not there.

Sound quality was nothing to rave about but was probably about average given it's size and isolation style. However, while running, the wires did bounce quite a bit and the resulting noise from that managed to obstruct the music. I was able to somewhat resolve that issue by using the wire clip to attach to my shirt.  Ambient noise is pretty apparent as well. These earphones aren't meant to block out surrounding noise so if that's what you want then you're out of luck. That or you just max out the volume to hopefully drown out any other noise.

The biggest issue I had with these is that the inline remote wiring was extremely faulty. I may have gotten a defective pair but I need to share my experience nonetheless. On my first run with these I used my newer Ipod Nano. As I started running I immediately noticed that the songs kept on skipping randomly. At first I thought maybe I had the nano set to shuffle when shaken but that was not the case. It kept on doing so until I finally clipped the wire to my shirt to lessen the bouncing of the wires. That helped somewhat but every so often it would still skip spontaneously.

Second run, I decide to use a different older model of nano thinking that it might be an issue with the player and not the headphones. This time around it was worse. Skipping, volume changing, pausing, unpausing...it was basically all over the place. On top of that, the right earphone was going in and out.

In summary, I think the design is great for the purpose (running, working out, etc.) however, the audio and functionality are totally non existent. Even if the wiring on my unit was defective I can only see that a working unit would eventually go bad based on the flimsy wiring alone. I'm no audiophile as well but I just thought that the sound was subpar for headphone at that pricepoint.

Anyhow, I don't recommend these headphones as there were easily more negatives than positives.
1942674
I bought these for working out, as I don't like earbuds while working out and these seemed compact and streamlined. I was pleasantly surprised at the sound quality, and I hardly noticed they were there during my workout. I might get a second pair for everyday use :)
4892581
I have had these headphones for a few months now and I am very happy with them.  I was looking for a pair of Bluetooth headphones to wear for working out at the gym and for running, and when I saw these were getting good reviews from various sites I thought i would try them out.  While the sound isn't quite as good as my wired headphones I previously purchased for about the same price, they are pretty good.  I personally find that the amount of bass from these headphones is more than adequate.  I personally don't find any issues with the headphones when I exercise and am glad that they are one of the more lightweight Bluetooth headphones.  I am sure if you upgrade to the $400 range you can get better sounding headphones, but for the price / weight / sound quality that I get out of them, I am a happy camper.
3339774
The sound quality is good.  The charging case is a plus.  Unfortunately for me I just couldn't get them to stay in my ears.  I tried the stability feature and larger rubber ear fittings.  They just kept falling out which took focus away from my workout.  If you don't plan to workout with them they work great.
1873218
Pretty good sound from these. For an affordable blue-tooth set I am fairly satisfied. Some things to note:

- A good fit is imperative for good sound on this model. There are numerous attachments and accessories which are provided to maximize the likelihood of a perfect fit. I have achieved a good fit,  but it still comes loose during activity. I still need to try more variations on the attachments.

- Sound when you find the good fit is excellent. Bass is strong and clear.

- I wear this to the gym and wear wicking shirts, The rubber band which wraps around your ear sticks to my shirts and adds to the challenge of the perfect fit as it creates additional pull on the earpiece. I needs to be adjusted many times in a normal workout.
4033982
Sometimes I get some feedback and they begin to make my ears sore after long periods of wear (over 30 minutes).  I use them every time I go to the gym!
3768453
These are very decent sound quality - good bass, good balance, good volume, no static after several uses.  I use them when I work out, and the rubber ear piece stays in my sweaty ear too!
3870590
The average/basic sound quality is to be expected for a pair of headphones on the cheap end of the market, but thats actually what I wanteda basic pair that I can throw in my bag and use when not wanting to lug around my bulkier Bose noise-canceling headphones. Theyre comfortable for my ears because they have the ear clip, although I sometimes have to adjust it a couple times to get them to sit correctly on my ears. The one weird thing is that the length of wire going to each earphone is not the same, so one earphones wire dangles more than the other. Im not sure why they designed it that way; its not hugely annoying but sometimes I find I get caught in the longer wire. I like the blue color.