This reply is not really helpful to the OP, but it might be helpful for future readers who are toying with buying the AKG K271 MKII 'phones. I was just reading this thread, and after having just bought a pair of the K271 MKII's, I was feeling a little underwhelmed with their performance on the low end (I feel that the upper register & the mid-range are very well done). That being said,
don't underestimate your eq settings!
I found that I loved everything about the MKII's except the low end. I love the comfort, the looks, the features (dettachable mini-xlr, sound-mute switch, auto-adjust headband), & the balance they have between the highs & the mids. There are several posts here at Head-Fi that talk about the MKII's having a fairly neutral sound, and I agree with them. Being a bass player though, I like being able to pick out the bass riffs in songs or to occasionally be driven over my dance threshold (see Christian Finnegan) by a tight sounding low end beat.
I've been listening to my MKII's using my phone (HTC Incredible) & the doubletwist app, and powering the headphones through an iBasso T3. I found that by utilizing the equilizer on the doubletwist app, I could get the low end sound I was looking for. A perfect example of this is listening to Bulls on Parade by Rage Against the Machine. The tone that the bassist is using is absolutely rediculous sounding, and I found that by tweaking my eq, I could get a sound that made me smile. Afterall, I think its fair to say that the enjoyment we get from music is the reason we spend the time & money we do to get the setups we have.
As I said, its not really helpful for the OP, but if you're reading this post & are on the fence about the MKII's because you are concerned about their low end, do what others in this thread have recommended: Buy them, listen to them, play with your eq settings, & decide. You can usually return them to most places if you don't like them. Having played with my settings, these cans aren't going anywhere but on my head!
By the way, an equilzer is not meant to dial up the volume of a particular frequency band so you can hear more bass or treble. Its reason for existence is to compensate for audio inadequacies in a particular set of equipment or in a space. Check these two good reads on frequency response & equilizers.
[size=medium]http://www.ecoustics.com/electronics/products/articles/131062.html[/size]
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