Could be production variation? We've been down this road before with the K550 where I heard two nasty ones, one kinda bad, and finally one pretty darn good (confirmed via measurements too.)

Don't think it's cables since same behavior happens if I swap them. Also the HD plots are fairly close with the cable swap. Nothing obvious.

I don't think it's the cables either now. When I questioned the cables, it was because of some jacks worked well with replacement cables despite them having only one ring on both sides. Some didn't though, like the jacks used in the O2. I appreciate that you took the time to repeat the measurements. I never questioned the accuracy, only the differences between the ones you took and the ones on IF...

Quote from: Tyll Hertsens on November 18, 2013, 03:25:29 PM

Do you think there may be an acoustic leak from the jack hole?  Maybe try pluging the unused jack with a bit of bluetack and measure. V-Modas come with a rubber plug to seal the unused side. Just curious.

That, was it!

...Which you seem to have figured out? 
Did plugging the hole change the sound any?

Regardless of the outcome, I think the HP50 is a really good headphone as well. I love the bass, it's very well controlled yet with good extension. The treble sounds a little shelved, but it still has enough sparkle and never feels lacking. I'm still thinking it's possible production variation after listening for siblance again in the 3-5k region, which I really don't hear even when compared with other headphones.

Could be production variation? We've been down this road before with the K550 where I heard two nasty ones, one kinda bad, and finally one pretty darn good (confirmed via measurements too.)

FWIW, Paul Barton talk quite at length with me about having to beat the shit out of the manufacturer on an ongoing basis about quality and repeatability issues. Seems to me these shouldn't suffer from unit to unit variations...much.

D'oh! I meant "shouldn't"...fxt.

D'oh! I meant "shouldn't"...fxt.

  Impressions wise, and going by IF's review, I don't think we see these cans that different though: warm, punchy, with well extended and tight bass, good balance in the mids, slight boost in the mid-treble, and not as airy and open as open headphones.

I felt, like Tode, that there was something going on in the upper-mids and lower-treble, but proly not bad compared to other closed type cans.