Harmon Kardon Classic On-Ear Headphones - Reviews
Pros: Detailed reproduction of the frequencies it does cover. Compact when stored. Attractive. Made of metal.
Cons: Incapable of reproducing bass. Uncomfortable if worn for more than fifteen minutes. Unwelcome iPhone controls.
In my recent quest for a new set of cans, I took a slight detour into the land of flashy prosumer headphones, in the form of the HK CL. The only reason I tried a pair was the price: half off, which equals $99. 
My first impression, upon opening the package, was of a quality product. The CL has a look and feel that makes it seem like the perfect match for an iPhone, iPod or iPad. They are such a good match, they may as well be Apple brand, instead of HK. Before I had a chance to listen, two things had to happen: I had to replace the headband—the package includes two sizes—and I had to let the headphones break-in, because it couldn't possibly be that they so totally lacked any authority in the bass department. Not a pair or sealed, over-the-ear headphones that retail for $200—or could it?
After about forty hours, I had a sneaking suspicion that the understated nature of the CL's bass was... understated. I would even forgive them if a more powerful amp brought back some bass, and that they were not as good a match for the iPad as advertised. No such luck—even relatively benign material like Lindsay Stirling so totally lacked bass that it was as if I was listening to a violin solo. Deadmaus? Forget it. Imaging was good, the sound was relatively uncolored... and the bass response was a slight wisp—just a "hint-o-bass," to whet the appetite of the neophyte.

In this world of bass-heavy headphones, there surely is room for cans that focus of the higher registers, and aim for clarity over boom. The HK CL does that, to a point. But it is inexcusable that they cannot even compete with a pair of B&O Form 2s in the bass department, and overall the design sacrifices too much comfort in order to achieve an aesthetic effect. In the end, they were not worth keeping, even at half-price.
Here's where I stand on bass quantities:
AKG K701 - A bit light
Creative Aurvana Live! - Just right
Sennheiser HD380 - A tiny bit heavy
If your pair faulty? I love the CL for their mid and high but not the bass. However, it is not because it is bass light, its bass is not tight at all. I also own Amperior, Q701, UE900 and other headphones and earphones.
Pros: Wide dynamic range, natural tone, fidelity, handsome casing, durable, class-leading
Cons: midrange can be too bright at times
When a name like Harmon Kardon announce a line of headphones, most people listen very carefully. 
I'm on a tablet computerand don't have time for a full review, but these are great, and mark a very strong début for H/K into the saturated headphone market. I bought these on a whim (solely because I noticed they were H/Ks lol) but i dont regret it at all. The bass is very present and enveloping, though it never overpowers anything else. Lots of resolution and detail in the highs, a warm and clear middle section. Vocals really shine with the CLs. They are built entirely with metal and feature a very stylish and time-honored look. The memory foam ear pads are attached magnetically and can be removed for whatever reason and they're pretty comfortable... though the smaller optional headband can clamp harder than the larger size. (yes, they give you a choice in headbands)
Bottom line: For the price, these are great headphones for listening to on the bus or in the studio hooked up to a nice DAC. They have the stylistic allure of Beats with the aural performance and durability of a nice pair of Sennheisers... witnout their characteristic 'dark' sound.  
I dont see how they've been overlooked as much as they have. These are serious headphones. 
Check these out, whatever you do. 
good review, CL is one of the most under rated headphones
Pros: Wide dynamic range, natural tone, fidelity, handsome casing, durable, class-leading  <<== yes
Cons: midrange can be too bright at times  <<== not quite if you hook it up with decent dac and amp
My only complaint is uncomfortable after 20-20 mins