[melat0nin]

Hi all
 
I've just received my K451s, bought new from eBay (I know I know, but the seller has stellar feedback so I decided to take the risk and they were only a tenner less than the next cheapest retailer -- possible false economy though!).
 
Anyway, on first listen I'm very disappointed -- the treble sounds incredibly muffled, especially compared with my earphones (RHA MA-350s) which sound crystal clear in the highs, to my ear. I'm wondering if perhaps they need burn in first, or perhaps I've got too used to the bright treble of the RHAs? Maybe this is what a more neutral set sound like... but I'd have expected a set of 'phones that retails at £130 to sound demonstrably better than ones which are a hundred quid cheaper!
 
I've read that the previous model (K450) had a lot of issues with fakes, but I don't know if the same goes for the K451s. The packaging all looks legitimate and the phones themselves feel solid, as do the accessories (the hard case is especially nice).
 
I've emailed the serial number to AKG to ask them to check whether it's in their database, which will obviously be definitive.
 
In the meantime, I wonder if anyone else has had experience with the K451s or has any tips?

 

[melat0nin]

Well I just received a reply from AKG (very quick of them, to be fair) saying they are genuine. Am pretty gutted, I was really looking forward to these being my next workhorse 'phones. Guess that'll teach me to buy before auditioning.

 

[russelk]

My K451s just arrived today, also from an Ebay seller with great feedback. I've also noticed the muffled treble and I've been burning them in for the last 12 hours or so. I will continue to burn them till they reach the 48 hour mark, then try listening again. Has yours improved at all?
 
In my experience, burn-in has not always made a difference to 'cans. In the case of Grado SR125s it made a world of difference, at first they also had muffled treble and a generally lifeless sound. After about 48 hours of burn-in they changed totally and went to having too much treble! The last set I burned in was the Audio Technica ES5 and no amount of burn-in improved these at all. I gave them away eventually.
 
I'm hoping the K451 will improve. I listened to the K518 DJ at a shop and they sounded very good, no muffled treble at all, which gives me hope about the K451.

 

[melat0nin]

Thanks for the reply russelk.
 
I've not been listening to them to be honest - I can't imagine that any amount of burn-in will change the sound as much as it would need to for me to be happy with it, although I guess I am open to it -- how did you get on with burning yours in?
 
After I bought them I did some recce in some local hifi shops and tried some other models (including higher-end stuff like Bose AE2s and Grado SR80s) and that taught me that a don't like the sound of a lot of units I tried some ATH E55s too and they definitely sounded better, but not by much.
 
I've concluded that the sound of the K451s is simply more neutral and balanced than the sort of sound I prefer, which is a more v-shaped signature. My plan now is to ebay the K451s and set about trying the RHA SA950is, which if they are anything like the MA350s I already have, which I love, will be awesome.
 
Moral of the story: high cost is no indicator of (subjective) good sound quality, and listen before you buy!

 

[russelk]

3 days of burn in has made a world of difference, I can now listen to them without cringing. The treble has opened up a lot, although still not as open as I'd like. Ultimately, any headphone maker has to save something for the high-end models, if the K451 was perfect then no one would buy the more expensive ones. For what I paid, I'm happy to use them as my day to day cans. For serious listening I have my Denon D2000. Sometime next week I'm going to take them into that store where they had the K518 and I'm going to compare them.
 
I would still recommend that you run them for at least 72 hours uninterrupted before you decide anything. The first 48 hours don't make much of a difference, I checked on them every few hours. At some point on the 3rd day the sound suddenly changed for the better. I'll continue to run them every night for another week or so.

 

[melat0nin]

Thanks, I'll give that a try. Fingers crossed!
 

 

[mikefromcali]

I purchased the k451s off the manufacturer website harmanaudio.com and I was very disappointed in the quality, very muddy and muffled sounding. I'm in the process of returning them

 

[egale]

I purchased a pair a couple of weeks ago. My problem is with sound isolation. They block out 0% of the surrounding noise and almost seem to amplify it. I can't listen to anything with them unless the room is totally quiet.

 

[scatcatcnut]

I got my 451's a couple of days ago. They are absolute garbage. Too bassy too quiet too distant and dire treble. Am used to sennheiser mx471.Infinitely superior.