Buyer beware, these are bad.
589143
Wish I could give them no stars.  Worst designed wipers mounting system I've ever used, basically impossible to install on wiper arm (instructions are basically useless).  I finally just gave up and threw them in the trash.  Note, I'm not exactly an amateur, Ive been working on cars for over 40 years (brake jobs, tune-ups, replace fuel injectors, install exhaust systems, etc.  etc.) and I used to work in the pits for an SCCA race car.  So, if you elect to purchase this brand, just be prepared to return them, or to toss them in the trash.
885017
Boy, I've run into bad headphones before, but these top them all! And the $79.99 retail price? Either someone at Polk is smoking something or this is one big practical joke. Perhaps both.

First the positive, cord seems fairly resistant to tangles and the base of it fits nicely past my iphone case without issues. Also get a 2.5mm adapter and many earplug adapter options.

Now to the horrible:
1) absolutely no bass, everything sounds like a tin cup with a string- music, podcasts, everything. Even laying on the iphone EQ settings didn't help much.

2) Absurdly useless ear clips. I don't know what mammal or fish species was used as a model for testing the fit, but whatever it was it certainly was not a homo sapien. They are flexible material which I suppose are designed to ease the wrap-around connection to the ears. BUT the same flexibility means they immediately start undo-ing themselves as soon as you finally wrangle them around your ears. And don't bother moving, they will fall off and trip you.

Polk should be ashamed to have put their name on this, and I'm embarrassed to have paid $10 on clearance for them. I was warned, looked at the Amazon 1-star reviews and thought "no way they could be THAT bad!". Well, add me to the 1-star reviews, even at ten dollars they are a complete rip-off. To think the office supply store I purchased these at actually had a theft-protection alarm attached to them! Anyone who stole this headset and tried them out would probably drive to the police station and beg to be arrested for grand theft stupidity - yes these headphones will drive you to madness!

Save yourself the time and trouble, avoid any of the Polk headsets in this family- I'm guessing the model down from this has needles in them to stab your eardrums (even that might be an improvement over this model!).
2336549
I bought my first set, and, after taking weeks to get to me (I guess they don't keep a big stock), they went bad within a month.  The wires frayed inside the cable, near the plug.  The left bud gradually went from fully working to cutting in and out when walking to no sound at all.

I exchanged them (they broke within the 30 days), and waited almost a month for the next pair, and the exact same thing happened, only in the right channel.  This time, unfortunately, 1 day to slowly, so now when I return them, I will have to pay the restocking fee.
2440612
I think I finally learned my lesson about these "inflated" Amazon reviews.  Bought these in response to so many positive reviews.  Big mistake.  I would give these no stars if possible.  Sound is horrible, fit is worse.  And the bluetooth connection; worse than that.  Only used them twice, and will not be using them again.  Would not stay connected for more than a couple minutes at a time.  Not worth the trouble to send them back; probably costs more in shipping than its worth.  Maybe next time I'll listen to my son and stop buying this "bootleg stuff."
144386
I received these as a gift and I've honestly tried to like them, but I can't.  There is a constant hiss in the background that can easily be heard when listening to quieter music and podcasts.  There is also an electrical interference noise that can be heard only in the right ear cup.  Additionally, when audio gets quiet enough, the speakers shut off with an audible popping sound - it's absolutely infuriating if listening to a track that fades in and out, or conversions with pauses (a podcast, for example).  I can't recommend these and unfortunately I can't exchange them since they were a gift - oh well.
2983113
PLEASE, I beg of you, DO NOT BUY these reeds.
I bought them because-duh-they're about 10 bucks cheaper than a box of Vandorens (my typical reed). I was low on cash at the time of the purchase, so I figured "why not?"
Worst decision I ever made.
First off, they aren't the correct size for a B flat clarinet. Comparing them to a name brand reed (Rico size 3) reveals that they are about 1-2mm wider than the typical reed, which makes them not "play" or "vibrate".
Second off, they molded practically a day after I received them. I normally soak my reeds in water before using them to soften them, and I've been doing this for years without a single hiccup. So I soaked half, leaving the other half dry. All of the reeds, even the dry ones, began rotting worse than I've ever thought a reed could possibly rot.
I threw them out without taking a picture, so I apologize for the lack of one.
Spend the extra 5-10 bucks on Vandoren or Rico reeds. I've used them for years with no issues at all. Vandoren even has a warranty on their reeds and humidity control packaging.
Definitely never purchasing from this brand ever again. I'd give less than a star if I could.
614462
Cannot express how much trouble these have been.  Sound over Bluetooth was horrible.  Logitech hep was the worst I have ever encountered.  Rude and incompetent.  Took hours before they just sent me a replacement that had the same problem (horrible sound from bluetooth).  Now I am using them with the mini usb and it keeps disconnecting.  Sometimes it will last a week, sometimes an hour, then it will disconnect.  The software for connecting rarely works.  My workaround is to install the other pair thay sent me, then they will work for a while.  When they quit connecting, I connect with the other pair.  Sometimes neither works. Sometimes I have a meeting that requires them and nothing works and I am forced to use my computer mic and speakers.  DO NOT BUY THESE.  IF YOU BUY THESE, YOU ARE AN IDIOT.
49366
Worst headphones i have ever used!

They were cheaply made, sound terrible, uncomfortable, and all around bad.

The build quality was terrible. I have $30 headset that is dying and the build quality is still better then these pieces of trash. I picked them up and they felt more fragile then a baby. I imagine that if you drop these eve once they will break.

They sound worse then those cheap speakers you find in those talking birthday cards. They cant go high, or low. And even the mids sound washed out and gross. When they have to go either high or low they struggle and make a rattling noise. I tried listening to Bohemian Rhapsody by Queen to test them out because the song does all octaves and such and it sounded flat and nasty like they were playing out of those cheap headphones that came with your walkman in the 90's.

They were so light that they felt like they would fall off my head if i sneezed. Light headphones are nice but not this light. And the ear cups have this weird plastic thing inside that push on the tip of your ear for what seems like no reason and its really uncomfortable. And the padding while it looks soft and comfy has no support and its like having just the plastic on your head and ears.

They are just all around a piece of garbage and i feel bad for anyone who bought these at full price. Ive used headphones from a $1 store and they were better than these in every way. To think this is sennheiser's mid/high range headphones makes me worry about the rest of their headphones. I highly doubt these were broken as there was no marking or anything on them and i doubt it was that they malfunctioned or anything because ive heard headphones like that and they didn't sound anything like this. Please, for your sake don't buy these. they are just so bad!
3541188
DO NOT BUY THESES!!!  I had exactly the same experience as many of the other reviewers.  I bought them 12.5 months ago.  They sound great and they sound better and better as they break-in.  The problem is the poor design and poor plastic quality. Reading all the negative reviews I treated them with kid gloves - totally babied them and never so much as set them down on a hard surface.  Nonetheless, the same fine cracks formed around the earcup holders and then a piece just cracked right off.  I can see the tiny cracks spreading.  Denon used to be a highly reputable audio company, but this product is a total lemon.  They should refund, replace or repair for free but they won't as it is just barely out of warranty.  This level of designed self-destruction equivalent to the Microsoft's xbox red-ring-of-death fiasco.  Sadly I will never buy another Denon product.  Back to AKG for me.  Shame on you Denon!

UPDATE!  Wow! It gets worse.  Incredibly Bad Customer Service.  Not only are these poorly designed and manufactured, I was astonished at how bad Denon's customer service is.  They do not stand behind their products at all.  I contacted them and nagged them into giving me a return authorization because the ear-cup holders completely disintegrated 13 months into a 12 month warranty.  I sent it to their repair sub-contractor, Panurgy.  I heard nothing for weeks.  Panurgy would not return emails or phone calls.  I had to simultaneously get Denon and Panurgy on the phone at the same time to get any response out.  Panurgy claimed my headphones never arrived.  But I had detailed tracking information showing that they had arrived weeks earlier.  Then the head guy at Panurgy claimed that the USPS tracking information is completely made up to fool customers and that the USPS routinely lies.  I had to call USPS to verify that their tracking data is valid and not part of a vast USPS conspiracy.  An hour later my headphones miraculously showed up at Panurgy.  They claimed they were dropped off on the loading dock at lunchtime (this is a month after the USPS tracking info said they were delivered).  After several more weeks of being in the dark about the repair progress and having to ping Panurgy and Denon on a weekly basis.  My headphones were returned.  The broken parts were fixed.  However the plug doesn't work correctly anymore.  It was perfectly fine before I sent them in for repair. Every device I plug it into I only get one channel or two channels intermittently.  The plug is sealed so it's not a loose wire.  I hate to be paranoid but it seems like Panurgy vindictively f-'d up the plug to stick it to me.  I have complained about the distasteful, unprofessional, and unethical behavior of Panurgy to Denon.  Denon has not responded at all - even with an apology.  What a bunch of untrustworthy schmucks.  There are too many other audio companies who do great work to justify dealing with these jerks again.  Epic FAIL.
1267122
These are advertised as "hand made."  And they sure are.  As in poor quality control, poor consistency, poor construction, poor sound.  They have all the benefits of a product made by some teenager in his basement.

Quality control is poor.  One of four shredded upon installation before even coming up to tune.  And, yes, I followed the "manufacturer's" instructions to the letter (use pliers to make a sharp 90 degree bend, then cut).  25% waste is not acceptable.

The sound is poor.  These have a tinny sound inconsistent with quality bass strings.  Alas, this is not consistent from string to string, most noticeable on the third string, but also evident on the second.  Not the rich tone of a true round wound, nor the thump of a flat.  As stated, the consistency is poor.  It would almost be better if all four strings had the same tone, because then we could just say they were poorly designed.  These are poorly manufactured ("hand made").

The feel is poor.  I disagree with those who say these need lubrication to handle slides properly.  These feel like mushy round wound strings, although sliding is no problem.  Still, it's hard to get the left hand feel necessary for decent playing.  Basically, they're cheap round wounds dipped in paint.  I haven't played them long enough to see whether the paint stays on or not.  Other reviewers suggest it just chips off after a few days.

These strings only have two things going for them.  First, they are billed as lasting upwards of double the life of an uncoated string.  Maybe so, but given how nasty they feel and sound, that's hardly a benefit.  Second, they look great, especially on my black JT Viola bass.  Shame we have to listen to them as well.  If you want cool looking strings you can hang on the wall, you'll love these.  If you want acceptable sounding bass strings, these are not the way to go.  So let's just look at them and not play them.
1545123
BUYER BEWARE!!  THESE SPEAKERS ARE BAD NEWS.

* Excellent Packaging and Speakers Looked High Quality When Removed from box.
*  Mounting Hardware Consisted Of Two Extra Long Flimsy Pieces Of Wire
*  Needed to Pay A Professional $85.00 To Install Them Because They Were To Wide and My Side Panels Needed To Be Cut To Make Them Fit
*  Virtually No Bass With These Speakers Which Totally Sucks & They Have A Crackling Sound - My 16yr Old Speakers Sounded Much Better. Now I'm Stuck With Them Because I Already Wasted So Much Money Having Them Custom Fit Along With Permanently Damaging My Side Panels.

I REALLY HAD HIGH HOPES AFTER READING REVIEWS AND SEEING THE QUALITY COMING OUT OF THE BOX.

NOW I TOTALLY REGRET THIS PURCHASE.
1283677
(NOTE: The company that is selling these is not BlackBerry. They are a third-party company who has advertised these headsets as BlackBerry brand. Don't be fooled by the link that says, "by BlackBerry," underneath the description above the photo above. Although what you receive looks very similar to the real BlackBerry brand headsets, these are not the real deal.)

Total crap. I ordered 2 of these headsets for spares to have around the house and car because the ones I had ordered here several months before were truly BlackBerry manufactured, which are great. These last 2 pair look and sound like knock-offs. The sound is terrible.

Just to make sure that I could give a legitimate review on these I plugged them in to my tablet to watch the same video I watched with the good set I have from long ago. The difference in sound and quality is immensely disappointing between the first good set and these 2 fakes. In addition to a solid sound check, I tried pulling them apart to inspect them more closely and on closer examination saw that they are NOT what is shown in the picture with this advertisement, although they do look similar enough to fool the average buyer. I am throwing these newest ones out as I am past the 30-day return period.
1056470
I bought 2 pair of these, and after opening the first pair I was sure these were the worst speakers I had ever heard.  So I let them break in for about 100 hours.  Still the worst speakers I have ever heard in my life.  Highs were way overblown and strident, and the bass was lacking.  I experimented with polarity many times and never got these speakers to sound good.  Just for kicks, I decided to open the second pair and they sounded GLORIOUS !  Wow, what a difference.  Even right out of the box they sounded great.  Something is definately wrong with my first pair.  I listened to the second pair for about a week, and then curiously switched back to the first pair, and once again they were awful.  I listen to them for short periods of time  and cannot stand them, so I shut off my music and go do other things.  I will definately be keeping the second pair, but sadly be returning the first pair.  In the end it cost me money as I had already bought a new brand of speakers because the first Wharfedales sounded so bad.  There obviously are some quality control issues at the factory.  I have researched this and found the same problem on a forum.  Most people thought the guy was crazy because everyone likes these speakers so well, but now I know what he was dealing with.  And also, the bad sounding pair came with a damaged tweeter grill right from the factory.  The second pair were wonderful, the first pair are awful.  In the end I am glad I opened the second pair or I would have given a negative review.
4670143
Do not buy. You'll be paying ten bucks for garbage. I have had them for a little over a week and a half, and then all of the sudden it when it plays my music, it keeps switching from my phone speakers to the earbuds, and when it plays from the earbuds the lyrics are barely audible
304016
These are NOT what they say they are! Scam... don't buy!
4683014
I originally purchased the QCY branded QY8 headphones and really liked those.  I decided to purchase another pair and thought I would try this brand...they looked exactly the same and they both said "QY8".  Plus, these were $2 cheaper .  But, they aren't close to being the same.  This came in packaging that looked like it had been opened.  The instruction book was for QY7 earphones. Not all of the extra rubber pieces pictured in the Amazon ad were included.  After charging and turning them on, the "power on"  voice was heavily accented and distorted to the point that it wasn't clear what was being spoken.  When I tried listening to music through these headphones, I couldn't stand to listen for more than a few seconds.  The harmonic distortion is unbearable.  I am talking teeth clinching unbearable.  I mean these earphones don't measure up to a 1960's era handheld transistor radio.  These shouldn't be sold under the category of wireless earphones, they should be sold under the category of wireless torture devices.
4359589
Buy these only if your eardrums are made of Kevlar. These are the worst sound reproduction devices that I've ever heard, scratchy and tinny distortion with no bass. If you suspended them under your house, they might perform as an adequate rodent repellent system. There are plenty of decent earbuds out there for similar cost, that sound exponentially better than these. These were so bad that I just put them back in the envelope after the first listen, and then misplaced the envelope for a while. I got them out and listened again tonight just to make sure. There is no mistaking. These are horrible.
It should be against the law to take money for a product that is as bad as this MEE audio Sport-Fi M6 earbad. Really, really ear BAD.
I'm sorry to say that it's probably too late for me to return them.

An alternative earbud that I have liked much better are the Sentey Oryon, with three different screw on resonant chamber backs to alter frequency response curves.