A buddy and I were talking about this thread. I sent him the link and he, too, was perplexed by the issue Amir is noting ~600Hz. And, he made a really good point about this being an example of why accepting a single unit for test is problematic for not just the inability to check for QC error but... (his quote):
If he's asking for people to send him a single speaker to test, then for sure they aren't sending it in the original packaging designed for a pair of speakers (FYI the box is huge on the ELAC's because they have thick foam.)
And, honestly, I think he makes a very fair point here. Do we know how the speaker was shipped? Is it possible it was damaged or banged around in transit due to not being packaged in the OEM packaging? And, is something members should be mindful of when sending in a single sample? It just seems
unlikely (not impossible, mind you) this is a QC issue. I'm not trying to make anyone look foolish for bad shipping... crap happens. I wrapped up an amplifier a few months ago like a TANK and it showed up with dented fins and I had to refund the buyer and deal with UPS over it.
(yes, I understand there is additional cost with sending a pair as well as the "hey, if it comes from the factory bad, it's not my issue". Totally get that. But if sending in the OEM packaging, it might not be as bad, especially for bookshelf speakers and would go a long way toward the science of things here in cases just like the one presented here)