Luxilon blah blah blah, RPM Blast blah blah blah. I hear those strings all the time but here’s a string you rarely hear anything about. I stumbled across this polyester that’s been under my radar for a long time: Head Sonic Pro 16g.

The data on Head Sonic Pro 16g shows this string has the stiffness of a nylon “synthetic gut” which is quite “soft” for a polyester since most polyesters are MUCH stiffer. But the data also showed a lot of tension loss. So I unfortunately stayed away from it for a while until I got a set from a trade and tested it out. WOW was I surprised.

What the data didn’t show is that after the tension loss this polyester stabilizes and maintains its tension and playability extremely well throughout the rest of its lifespan (polyesters are famous for losing tension AND playability VERY quickly). It’s one of the only polyesters that’s STILL in one of my test racquets because I can still play with it even after hours and hours of use. I kinda love it. Most other polyesters are absolutely garbage once they’ve hit their extremely short playable lifespan. 

I’ve known a lot of stringers who suggest a “soft” polyester such as Luxilon Element. However the data may not show AS MUCH of a lot of tension loss but what it doesn’t tell you is that the tension continues to drop and drop the more you play with it. Leaving you with a fishnet of a racquet. Not Head Sonic Pro. 

I also found Sonic Pro gave me lots of feedback and has amazing feel for a polyester. Many of newest generations of polyesters have a “plastic” and “dead” feeling. But as racquets have more and more “dampening” tech built into them, I think you want a string that gives you as much feedback as you can get. 

I also like that it’s still a THICK string. A true 16g. 1.30mm if you’re into metric measurements. I know the current trend is to use extremely thin polyesters (18g or 1.20mm and thinner) at the moment. But manufacturers thinning their super stiff polyesters and slapping a “more arm friendly” on the label doesn’t necessarily solve the problem. A smaller can of Coke has less calories but it’s still a Coke… but for those who want a durable and hefty string that isn’t ARM Blasting (junior players pay attention), Head Sonic Pro 16g remains one of my favorite.