Some rackets that I've played with make a great "pop" when I hit with them, and some just make a muffled "thud". What exactly causes some to make that sound and others not to? I just recently strung up my racket with some luxilon BB alu, and it just made dull "thud" sounds, but after putting some babolat vs gut in it, I get a fantastic "pop" and it feels like my shots are just better (whether this is an effect of the sound or the string remains a question.) Was the poly just not as good because I didn't generate enough headspeed for it? Is the "pop" sound a good indicator of whether you're hitting a shot well or if a racket is particularly well suited for you? It's just something I've been wondering about a lot lately.