Speaker wire selection for inefficient speaker?

@alexb76 , its fine to boost the center, that is why the receiver has that feature. If you want to change speaker wire do an upgrade for all of your speakers, Having said that I doubt the wire is whats causing the volume difference. I would just boost the center like you have and leave it.

A little perspective.  90+% of the problems are associated with too small a gauge wire. This is especially important for inefficient speakers.  So I always use 10awg wire for speaker wires.  From there you can spend thousands of dollars on the last few percent but the key is heavy gauge.

This is not valid advice, in my opinion.  Length times DC resistance per length unit tells you the series resistance a wire will add. A center channel wire under 6 feet long would not cause measurable voltage drop even at 16 ga.  But this kind of thinking made Noel Lee a very wealthy man!

That said, upgrading the wire to use better materials and construction may improve your listening quality…but not just heavier gauge OFC.  For example, Nordost White Lightning or Purple Flare are light gauge wires, but many reviewers recommend them for clarity, smoothness, and musicality.  Spend a few bucks and upgrade all 3 LCRs.  Other brands may suit you.  Look at Cardas too.

That is what the 5db boost is for. To equalize the channels for your seating position..