Good question. It does help diffraction to off-center the drivers. The better way these days is to round over the cabinet edges. I guess once they determined to off-center things, the rest flowed naturally.
You saw a lot of those in the 80s. JBL had some as I recall.
I don't know how old your current speakers are. Many older model speakers had different degree's of end of line testing. This whole MATCHED PAIR was somewhat of a marketing thing & somewhat real world. Most likely Celestion had a fixed end of line testing routine. They smartly decided they could use this test criteria & sell serial numbered & matched pairs. A good marketing ploy..........With most of today's GOOD major companies. I would consider Revel one such company. Well, such companies usually have rigid end of line test criteria. They have a reference standard which is picked from a defined production. The performance of this reference usually falls near the top of the group tested. Then they will put a small tolerance around this Ref. standard. This is the test criteria that will define pass & fail on ALL SPEAKERS!! Speakers that don't pass will simply be rejected & reworked or destroyed! I think both speakers will be very close.........YOUR SHOULD HAVE NO WORRIES!!
Well HFNRR used to test the FR of the two speakers they had for review, and it wasn't always good news.
Well it certainly doesn't hurt to match them. Although that bottom blue one looks kind of broken.
