I recently felt my strings to be very much less repulsive and explosive sounding after about a month of play. It feels as if I'm playing with a lower tension, unable to hit powerful smashes. The tension is still intact however, because when i push them against my fingers I can still feel that they're tight. But I no longer get the crisp power that I felt when I first strung it. This seems to have affect both my racquets, NS9900 - NGB98 and AT300 - BG66 both strung at 24/26lbs. Anyone have similar experience? Why does this happen?
Yes, 4 knots stringing. The stringer can be said to be fairly experienced. My racquets have never been exposed to extreme temperatures (unless you consider air conditioned room as one). They are always kept in my bag when not in used. And as mentioned, the strings are still as tight as I first strung them. The tension fall isnt that noticable. I read that the strings just lose their crisp feeling after a certain amount of time. That's why the pros restring their racquets all the time even though they are still in perfect condition. Correct me if I'm wrong.
Can you try hitting the string bed onto your palm to test for the resonance pitch? My guess is that the pitch would have dropped from your freshly strung state if you can still remember it or have a similarly strung racquet to refer to. Pushing your fingers into the string bed to feel the tightness is not a good test for the actual tension left in the string bed.
Maybe it's a sign that your technique has improved and now you need higher tension to play properly! Perhaps next time you restring you can increase by 1-2 lbs and see.
I have the same experience with NBG98 as well. I strung it with 25lbs but it lost tension by nearly 2 lbs after 3-4 sessions of play. The repulsion gets very "dead" when the tension become loose. I strung my BG66 with 25lbs too, but it does not seem to lose that much tension as that of NBG98, and the repulsivenss of BG 66 seems to be better when the tension gets loosen.
Almost all string would lose 10% of tension after 1 week. BG80 or zymax would lose 5%. After a month, string performance starts to go down hill. Nylon begin to lost its elastic. Two month it is done. If it isn't broken at this point, its play character is not the same as it was fresh.
Nanogy (both of them, but less so the 98) are notoriously "numb"; I tried each once and thereafter never again, as there was very little connection between hand and racket face. The Nanogies, oddly, get some feel back after they have been played for a while, but there's only one string for which I can tolerate a break-in period, and it ain't Nanogy.
All strings are like that. To me it's like a new spring, it works fine when new, as it gets older it still got some of the qualities but it's not quite the same.