Don't think it's a seal problem. These are full size open, and have measured the stock version with velour pads. I remeasured some other cans I have to double check my rig and things look good.

One may be conditioned by plots. However, I do hear cans before I measure. These did sound a little leaner in the bass area than even my HD558s. I don't think that's how I heard them before though.

Alex mentioned he did more mods to them after the meet, so they should sound different from then. At the meet I though the had more treble and more impact relative to the stock PM-1s. This time around the bass seems mitigated. I think they sound a bit brighter too because of this.

There is some driver dependency, and the impedance does seem to show a resonance at around 60 Hz.

That said, I measured these LCD-2s the same way I measured these cans. And so did the stock PM-1s, HE-500s, and all full size open dynamic cans.

I could however remeasure these with a non-leaky baffle (like I now do stats and closed cans). It would fill up the lower bass in the measurements, but results might no longer be easily comparable to other similar type cans measured with the leaky baffle.

I'll try with the sealed measurements later tonite to see what I get. I think the LCD-X did benefit from sealed measurements, but that seemed more an exception than a rule in regards to full size open orthos. Thanks for the info Tyll and looking forward for your review!

Ultrabike, thank you very much for your measurements and impressions posted. I really appreciate your effort!
    In my own measurements they go to -5db at 30Hz relative to the HF peak at its highest point.  They also have better extension in LF department  then the previous mod you have heard at the meet. Quoting you: Oppo PM-1 (mod) vs PM-1 original - Same as above, but perhaps a little more treble and bass on these. I think more bass you heard at the meet most likely can be attributed to a slight peak around 100Hz the other mod had which is now gone.
   They could still be better especially in LF though if my left driver was as good as the right one but unfortunately as mentioned before in the other thread my beta units came heavily unbalanced and had to be modded differently to match each other better while sacrificing the ultimate extension in both (left had much better top while right was much more extended at the bottom).  I am not sure but suspect one of the drivers in my unit was from beta-1 batch while the other was beta-2, either way when I spoke to OPPO reps couple of weeks ago they were very much surprised my left and right drivers measured so different while I thought it was a norm for a beta test sample :-) . This explains why OPPO wanted to keep all the beta impressions closed, when one deals with a pre-production unit everything should be expected.
   Good thing it looks like all the production units measure pretty consistent not only between left and right but also between different sets which tells a lot about their quality control standards.