Replaced blown woofer in an A/D/S L620 gen 2. It's not a robust as the other!

Bought a pair a of metal grilled A/D/S L620's know one cab had a blown woofer. I had ohmed out the good one to satisfaction, and bad one indeed was dead, maybe blown voice coil, etc. Bought the exact same part number woofer from ebay, and upon firing up my NAD amp noticed the right speaker needed me to advance the balance control to 1 o'clock for both speakers to sound about equal. I will try other methods like swapping speaker leads around, swapping the rear terminal/crossovers, etc. to see what gives. Anybody out there have any plausible explanations for what I'm seeing, rather hearing! I realize that's what the balance control is for, but all flat is how I grew up to understand how the setup should be. Thank you...this site is tremendous by the way!!!