I thought that I would add my tuppenny worth seeing as there are so few reviews for this product. I was a bit hesitant about buying these because of the lack of reviews but as they seem to be a newer version of the K450's which are very highly rated, I took the plunge.
I specified Superfi as the supplier because the default supplier when you click BUY on Amazon (caraudiosecurityuk) seems to have supplied some fake K450's according to some Amazon reviews.
My review is very subjective because I have not compared them to anything except freebies and the original Sennheiser PX200's which I was never happy with after buying them based on a What HI-FI review about 7 years ago... Golden Rule No. 1 - if you are serious about it, always, always, always listen to audio equipment before you buy! However, that is not practical where I live so I took a chance. Over the years I have spent a lot of money on hi-fi so consider myself a bit of an audiophile but these have been bought for travel/portability so I won't judge them based on home use.
They look good and build quality seems fine while they come with a substantial (if rather large) traveling case. Using the alternative iPhone cord with my HTC smart phone, the mic works and I can pause/play but not change the volume remotely. They seem slightly heavy for their size which adds to the quality feel.
I have had a quick listen with different types of music including classical and soundwise, plugged into my portable devices at home, they are much better than my PX200's. There is definitely too much bass lift but this will probably be beneficial on the plane and can be taken out with an equaliser. Otherwise, the sound without equalisation is fairly smooth. I would say the sound is good, rather than excellent. I am not, "..hearing instruments that I never heard before." but would expect to be spending £100-£150 on some bigger phones to be happy at home. The sound may improve after a few hours burn-in so I will try to remember to report back. Also, as they sit on your ear, positioning is important for sound quality and comfort. The most comfortable position may not be the best for sound. There is quite a lot of pressure from the headband to keep them in place which is less comfortable for me on one ear.
Summing up: Look good, nice build quality, no good for jogging, they press quite hard on the ears, not 'flat' sounding but for on the move and with personal equalisation, should do a good job.
Headphones are a very personal choice but I would recommend these.
UPDATE *** UPDATE *** UPDATE
Ok, it's now 2 weeks after I received these and my first reiew. I have a lot more things to add...
My first review was written within minutes of opening the box and I hadn't given these a sufficient audition and... I nearly sent them back! I should say that I am a critical listener, my current hi-fi having set me back about 10 grand. I like realism and a natural sound. I want to close my eyes and be in the studio with the musicians. I know that you cannot achieve anything close to audiophile performance for under £100 but as What Hifi's headphones of the year, they should be fairly good. I bought these as a 'cheap' travel pair although I still have not tried them on the move, resulting in a more critical evaluation at home.
I set the equalisation to flat on my high-end laptop and flicked thru a bunch of mp3s (ripped at 192 VBR using Exact Audio Copy)) on iTunes - mostly rock, blues and accoustic. The sound was extremely bass heavy and muddy in the higher ranges. So for 2 weeks I have been burning them in for 10 hrs a day with a variety of music plus the jslabaudio.com/burn utility (white/pink noise plus frequency sweeps) and I am relieved to say that they have now redeemed themselves. I guess that I am out of touch with 'consumer' headphones which seemed to be aimed at sounding good for non-critical listeners rather than audiophiles. Bass extension seems to be all that matters.
Rummaging through my drawers I discovered that I had more portable earphones than I thought... 12 year old Koss PortaPros (one earpiece detached but still functioning), Sennheiser PX200's , the original Bose In-Ears, Sennheiser in-ears (not sure which). To summarise in ascending order of sound merit:
PX200 - Just awful. These had a What Hifi award too and I have hardly used them
Bose In-Ear - just ok, but not really hi-fi
Sennheiser in ear - better but not outstanding
Koss PortaPro - Great value for money with a better, more refined and open sound but with an extended bass which doesn't go as low as the AKGs due to open-back design
AKG501 - best of the bunch but only after 2 weeks burn in...
To begin with, the AKGs were extremely bass heavy with muddy mids/highs. Two weeks burn-in seems to have improved everything. Now I would say slightly muddy mids and highs with an over-pronounced, but tight, deep bass resulting in a laid back and entertaining (rather than audiophile) sound if you can throttle back the bass. The damage seems to be at 125Hz. Cutting this by 3 small notches and increasing the 62 Hz by 1 small notch on my laptop equalizer seems to balance this out considerably.
I have also listened with similar results on my Creative Zen, iPod 3G, Sony CD Discman and driving through the headphone socket on a Harman Kardon hi-fi amp using the laptop/Sony Discman as source. With mp3s, a big amp didn't make much much difference so I don't think these a need a portable headphone amp. They seem easy to drive with most devices. I could hear the improvement over mp3 with the CD sources but it wasn't significant enough at this level of headphone.
I would give the AKGs 5 stars at the Amazon price if the sound was anything close to a flat bass response. Not that I use it now, but my Sony CD Discman only has a 3 position bass booster so it would be impossible to use it with these headphones.
If you are a bass-head who doesn't care about getting close to the original sound then these will be a high quality solution. For anyone else, make sure that your device has equalisation facilities.
On the subject of sound leakage. There is not much at normal listening levels although it gets worse if you crank them up. I would wear them on a plane but not sitting next to somebody in a quiet library.
I think that, soundwise, the Koss PortaPros are far, far better value for money at £21 (if they are not the fakes) and it seems that the only difference between the AKG451 and AKG450 (at £41) is an extra cable with contol and mic for an iPhone.
***** FINAL UPDATE *****
What a relief! After 3 weeks of overnight burn-in, the sound has got better and better. It is more integrated and balanced and with less bass exaggeration. I can now listen to some music with the equalisation flat. I have pushed up my rating to 5 stars and my only reservations are that they get a little warm on the ears which is to be expected with this type and the flimsy cables, which have not let me down as yet and can also be replaced. You just wonder how many times you can accidentally jerk or catch it on something which is pretty much unavoidable in normal use.
**** ADDENDUM *****
8-9 months into ownership and with very light use, the pin that connects the left earpiece to the headband broke. It was returned to the supplier, Superfi, who were very quick to send a brand new replacement after assessing the breakage. A big thumbs up to Superfi.
Although it is very subjective, the new phones without burn-in sound as good to me as the pair I sent back. I am wondering if any of the components have changed...