Turns out, 2 of the (three) drivers on the right unit had died. This was the first time I ever needed to “service” this kind of equipment, so I was relieved when he assured me he could repair/re-shell them without changing the sound signature.
While I was at it, I decided to switch cable interfaces to mmcx because the 2-pin type proprietary cables on the UEs had a horrible track record with me. Because it’s essentially a press-fit design, once it disconnects by accident (for whatever reason) the “grip” is compromised from then on out – so I end up having to struggle with signal dropouts unless I fiddle around with the connector.
Sufficed to say, I was done with the 2-pin design. Some people still prefer or swear by it, but it’s just not for me. Switching to mmcx on the other hand, gives me the benefit of multiple connections/disconnections – which even allows me to swap and test various cables often without worry.
The only drawback with this type of connector is that it’s more prone to buildup (grime, etc.) – which requires you to clean the contacts more often, a compromise I’d gladly take given with what I’ve had to deal with in the past. It’s one of the best decisions I’ve made.
Variations in the graph are just due to the fact that you can’t guarantee mic-ing them exactly the same way. But this this is pretty much the same way UE would’ve done it – he even sourced the exact same drivers and tubes as the original. And I didn’t have to worry about shipping it back and forth from the US.