Superlux HD 662 F

When I listen to these headphones, I can't believe how much I paid for them. I honestly believe their true value to be twice what it is.
Having said that, these cans aren't spectacular. The plastic is a bit too weak, the rubber covering the wire is easily scratched/cut, and the padding makes me ears a bit sweaty.
Now for the sound quality: The crystal clarity of these cans surprises me every time that I put them on. Also the high end is exactly what I was hoping for, which is to say that it is impactful, clear, sharp, and just a touch harsh.
The mid section is a little too recessed for my liking and the low end is a bit lacking. Both of which aren't a very big deal for me at all, but is you are looking for cans for rap/heavy metal(I had to eq the bass up to make listening to Eminem wholly enjoyable), then look elsewhere. If, however, you plan to listen to classic rock, most alternative rock styles, or anything close to The Gracious Few, then you will be delighted with these cans.
 
*EDIT* That review was with about 40 hours of burn in. I thought that the sound had stopped changing so I wrote that review. However, as I approach the 100 hour mark, the cans are really just now becoming completely burned in. I recommend to anyone that buys these cans: Let them burn in for at least 100 hours before making your decision.
Everything is finally completely settled as far as sound goes(I didn't realize that the sound was still changing).
The comfort has improved as the materials have begun to relax and give more. The highs are still just as sharp, detailed, and beautiful. The bass, however, is what has really changed. The overall quality of the bass has increase(more textured is the best way i can describe the change). It sounds as if the bass now goes further down, it has a deeper quality to it.
I also never feel the need to eq the bass up at any point, even while listening to rap. In other words, the bass has become more pronounced.
The mids I don't think have changed much if at all. However, with the increase in bass, the recessed nature of the mids becomes more apparent. That is my one and only complaint regarding the sound quality.
These cans sound so natural and real. When a snare hits, it sounds like there is an actual snare in the corner, not like a digital reproduction. Bass drums sound like bass drums should, and bass guitars have the texture to them to really allow you to enjoy a nice riff.

 
Construction and comfort
 
Clamping force is rather tight, but not uncomfortably so. It's possible to adjust the force simply by carefully bending the two metal bands keeping other parts together. The metal headband can make annoying (and very audible) sound when it interacts with the plastic part of the band and starts to vibrate. This might not be a problem for persons that have smaller head and it should be easy to dampen these vibrations with some easy modifications.
 
Pads pleather material feels slightly softer and thinner than the ones used in m50 but the general feel is just as good. They will induce some swetting just like any other similar pads. It is possible to change the pads with AKG K-240 pads just like HD668B pads were - I haven't tested their impact to the sound quality yet.
 
Isolation is pretty much the same as ATH-m50 provides, quite good.
 
Sound
 
The sound is clear, well balanced and transparent. Detail retrieval is excellent. All in all, I couldn't find any obvious flaws. As the frequency response is near-flat these phones shouldn't get too tiresome either.
 
Soundstage of 662F is *a lot* wider than ATH-m50. Players seem more closer to the listener with ATH m50 - soundstage is small but well defined. 662F is very spacious in contrast. Maybe even slightly more spacious than 668B! It's hard to believe these cans are closed.
 
Direct comparision to ATH-m50: 662F has less bass rumble but has similar extension. Bass is also tighter. 662F sounds little thinner due to having less lower mid emphasis. It also has brigher highs.
 
Direct comparision to 668B is harder as the cans have pretty similar sound signature. General signature in both is very neutral. 668B seems to have slightly more mid emphasis making 662F sound more "open" but "hollow" in contrast. Without direct comparision its hard to tell the difference though.
 
Currently HD-662F are priced 33€ (~$48) at Thomann.de. I goes without saying that they are huge bargain and similar value as 668B.

Just wanted to make some comments on the CAD MH310 - a rebranded Superlux HD662F. I will be referring to them as HD662F for the remainder of whatever this is im writing to avoid confusion . I bought a pair Superlux HD681 at the same time and will just compare the two, along with a few others.
 
- The MH310's seem solidly built; abit more sturdy than the HD681's and my old Samson SR850's (another rebranded Superlux). They have different pads from the HD681, SR850; they're thicker, softer, and more comfortable. One thing that bothers me a bit, there is very slight driver flex when I put them on or adjust them after a few hours of use. First time ive had this happen to me on a pair of full-sized headphones. Guess it might just be my pair.
 
- Comfort is pretty bad at first, at least for me and my big head =). They clamp pretty hard, but that's easily remedied by bending the top metal wires abit.
 
- Isolation is very good as expected from a closed headphone
 
-Sound:
General signature is slightly v-shaped. The mids on HD662F aren't as recessed as they are on the HD681s
 
= Bass quantity - HD681 = HD662F
= Bass extension - HD681 = HD662F
=== I can hear both go all the way down to 20hz with a similar drop-off between 20-25hz
= Bass impact - HD681 < HD662F
=== The HD662 hit pretty hard. Even harder than my FA-011s. I guess this has to do with the closed design.
= Bass quality - HD681 < HD662F
=== Bass seems more detailed on the 662Fs, again this might be because of the closed design (smaller headstage).
 
- Mids quantity - HD681 < HD662F
--- Mids are a bit under neutral for the HD662F (at least to my ears). Vocals seem more distant on the HD681.
- Mids quality - HD681 = HD662F
--- Mids on both headphones sound...'dry'. I hope im using that term correctly. Vocals seem to have less 'life' in them compared to my FA-011s and DJ100s. Sorry to use such vague language here, im still learning . Good mid detail and clarity on both headphones.
 
+ Treble quantity - HD681 = HD662F
+ Treble extension - HD681 = HD662F
+++ Both extend pretty well up to 16khz, drop off at 17khz and above
+ Treble quality - HD681 = HD662F
+++ Bright, peaky treble for both headphones, same with the SR850 (from what I remember). Im starting to think Superlux wants this as part of their house sound or something. It isnt really bothersome for me as im used to it, but with the HD662F's smaller headstage it can become fatiguing even for me. The emphasized treble creates a sense of air that helps contribute to the overall presentation.
 
@ Soundstage - HD681 > HD662F
@@@ Wider and deeper on the HD681 (SR850 is about the same as HD681 FWIR) because of the semi-closed design. The HD662F's is pretty large, though, for a closed headphone.
@Imaging, separation, layering - HD681 = HD662F
 
 
The MH310/HD662F sound pretty similar to the Samson SR850, just with a smaller headstage. I like them but do prefer the sound of the HD681's more, and will be returning the MH310's.
 

While I think the sound is "good" I would not call them excellent either.

The cable could be rubberized instead of a thin wall stiffer plastic with thin wires inside of it.

Sound isolation IMO really is average at best, just for example, I had kraken V2 pro, with EQ set/tuned for the 662F the V2 volume I only had to have at 25-30 and would more or less completely block out external noise, with the 662 or cloud stinger I have to have volume at 55-57 and even then can hear some background noise leaking in.

the material on the earcups is not "tucked in" like it is or could be on the 681/688 it just goes around the earcup and stays on via tension/tightness, my set is brand spanking new and already had the earcup material come off, which absolutely breaks whatever sound isolation should be there.

The earpads are not very "smooshy" they are comfy enough, but, because of the above mentioned issue and with the material not being squishy while the headband is "tight" enough, the earpads do not seem to either be deep enough, or, they are not squishy enough which breaks the isolation.

I have also found them not the greatest at sound separation. I play white/pink noise constantly, the Razer kraken V2 and the Cloud Stingers do not seem to have a problem blending the noise with games or whatever am doing, the 662F on the other hand seem to make sounds compete with each other.

Am sure if you were to use them for ONLY watching movies, playing games or listening to music (EQ for your ears) they are actually quite decent, but, the earpads need be deeper/squishier, the cups need be thicker (better isolation) and the cable needs to be a bit better made (more flexible and sleeved better IMO)

They are decent no doubt about that, but, the "bargain" factor does not apply as much when try to buy them here in Canada for just under $70 shipped, put in territory many other offerings are available.

That being said, they do come with a free 6.5/3.5mm screw on adapter and the size should allow to work on 90% of people no issues at all.