First of all, give us a little more info on the history of the tires. Were these tires used before your alignment was corrected? Which tires are on the front? Have you tried to rotate the tires front to back to see if the "hum" follows the es100's or the falkens? I suspect that your tires that are humming were not rotated and balanced properly and/ or your wheels were out of alignment which caused the tires to warp. If you can find which pair of tires are "humming", possibly by rotating , you can replace that pair and fix your problem. I've heard of es 100's giving alot of noise on the road. I put 30k miles on the es 100's and never had a problem with noise but I rotated them at every oil change.
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