i cannot quite make sense of this. but here it is: i have two main rackets that i use most of the time. a ARC10 and a 2/3rd gen AT700. when i first bought it from MK, i asked them to be strung at "24lbs". which later on was confirmed to be 23M/25C. the string job is 4 knots. both rackets after the initial string job felt good. lively and powerful. after the strings broke in both, and after i got my WASE, i restrung at the same tension, 23M/25C, 4 knots. i even kept the same pattern. the result feels different, the racket seems dull and not repulsive. it took much more effort in comparison to get the same bounce. so recently, i restring them again. this time i decided to do some experiments. using the same exact pattern and technique, i did: ARC10: 25M/25C AT700: 25M/27.5C the AT700 feels more lively than my previous string job. the repulsion and power is back. i didn't think that an 10% increase in tension would make that much of a difference. the only other difference i can tell is that the C/M ratio is slight higher. C is exactly 10% tighter than M. while previously it was less than 10%. the ARC10 is even more odd. it feels way more lively than before and power was also excellent. the most strange part is that after a hour or two at the gym, the tone of the racket suddenly changed. there is a distinctive "PAK" sound when i try to hit the shuttle hard. it was strange and sudden change. i went and checked that the racket and string are both fine, nothing cracked or shifted. the testing were done in two separate days so there is less likelihood that i just happen to feel good that way. i will continue to use them and see. but meanwhile, anyone can come up with an explanation? i wish i have more AT700/ARC10 so i can do more tension and M/C ratio experiment. but unfortunately i don't. and i am sure some of you remember my previous inquiries on what makes a string job better, most of the recommendation came back as consistency and doing little checks here and there. well this time i didn't do anything different with how i strung the rackets.