Good guess but I would point out that if it were something as simple as driving them to cone breakup then everyone using the same tests would experience the same thing, or at least higher than the reported 1% of the drop. The K7xyz are not "bass head" cans but they do VERY well with tight, deep, realistic bass just the same. Even at way above "normal" listening levels.
This is a QC issue.
They do VERY well with tight, deep, realistic bass at
lower volumes compared to other, more capable headphones. Because of the open nature of the K/Q7XX headphones, you get very little bass feedback, and because of that, some people are inclined to turn the volume up the hear the bass better. The downside is that these headphones perform poorly when reproducing bass at loud volumes (relatively speaking for these drivers. It's loud for these headphones, but quiet for something like the Beyer COPs). Therefore, for the people who turn up the bass too loud, it will distort earlier compared to other headphones, especially those with some reinforcement on the diaphragme membrane.
I cant agree with you. It dosn't matter that hp are bassy or not. That kind of dissortion is not acceptable.
On normal listening volume level, on this track
http://youtu.be/cQHTcJYJRgQ
right driver in my K7XX its just like "trytytytytyytyt". Thats not OK.
On K550 everything is fine, just clear, deep bass. Is K550 a bassy headphone?
You should.
I tried it, and my left channel rattles. I looked at the driver, and the left channel deforms more than the right channel. As I said, this is normal, and something like this is outside of manufacturing tolerances. If AKG had to test every driver at loud volumes, they'd be throwing away a good amount of them for the sole fact that it rattles 1dB higher than another driver. You can't get a normal listening volume on a bass boosted track anyway. When I first played it, I thought the headphones were too quiet until I heard the boosted bass. As I said, these headphones aren't designed for that type of usage. I wouldn't rank the K550 as a bassy headphone either. More on the warm side, imo. And guess what? The K550's drivers have reinforcement for cone breakup!
Standard K701 driver:
Standard K550 Driver:
As I said, AKG's K/Q7XX drivers are very delicate, and they aren't made for that kind of usage.
I think you don't know what you're talking about. If it was cone breakup the left and right drivers should do it equal or at similar volumes but that's not the case. On my pair I don't have to crank the volume to get the buzzing. It does at at volumes below a comfortable listening level (and I don't listen loudly). It sounds identical to the driver mechanically hitting something as it oscillates.
I know what I'm talking about, and all drivers aren't exactly equal. Therefore, you will have some slight variations to when the drivers start distorting. The same happens to my AD2000MKIV headphones (avatar pic), although at ear hurting volumes.
It doesn't make sense to complain about build quality of a headphone designed for listening to music when it only shows problems outside of what it was designed for; it seems these issues are only found when you play frequencies too loud that normally dont appear in music. This is why warranties only cover manufacturing errors and not misuse or normal wear and tear.
This is another good post. I completely agree.
Driver matching for channel balance =/= driver quality.
