It's just a small tape covering the bass screw hole in order to tame the bass and give more clarity to the mids, it's just a signature preference change.
You can try it very easy and remove the tape if you dont like the result.
For me I will stay on my rooted V4A Note2 Exynos and wait for more reviews on the new coming DAP's X5, DX90 and Calyx M.
A rooted 3S with V4A and a micro SD slot would have been just perfect for my needs. But the capacity storage has broke my dreams ;)