Playtest: HEAD Sonic Pro 17
By Greg Raven
Sonic Pro is a new polyester string from Head, the first polyester string it has added to its Control line-up. According to Head, Sonic Pro is a uniquely processed co-polymer polyester with extra combinations of resins and fibers. Head tells us that it designed Sonic Pro to be soft enough to give today’s modern, aggressive players the feel and control they want with the durability they need.
Sonic Pro is available in 17 in white only. It is priced from $13 for sets of 40 feet, and $180 for 660-foot reels. For more information or to order, contact Head at 800-289-7366, or visit head.com.
In the lab
The coil measured 40 feet. The diameter measured 1.22-1.26 mm prior to stringing, and 1.19-1.22 mm after stringing. We recorded a stringbed stiffness of 73 RDC units immediately after stringing at 60 pounds in a Wilson Pro Staff 6.1 95 (16 × 18 pattern) on a constant-pull machine.
After 24 hours (no playing), stringbed stiffness measured 64 RDC units, representing a 12 percent tension loss. Our control string, Prince Synthetic Gut Original Gold 16, measured 78 RDC units immediately after stringing and 71 RDC units after 24 hours, representing a 9 percent tension loss. Sonic Pro added 16 grams to the weight of our unstrung frame.
The string was tested for five weeks by 38 USRSA playtesters, with NTRP ratings from 3.0 to 6.0. These are blind tests, with playtesters receiving unmarked strings in unmarked packages. Average number of hours playtested was 23.9.
During stringing, Sonic Pro is similar to other polyesters in terms of stiffness and coil memory. It does have a smooth surface, which is very nice for weaving and pulling crosses. Sonic Pro feels as if it has a very light coating of lubricant, which also facilitates stringing.
No playtester broke his sample during stringing, 14 reported problems with coil memory, four reported problems tying knots, and none reported friction burn.
On the court
Of the 112 published string playtest reports to date, Head Sonic Pro rated in the top 20 in five of our nine categories: 6th overall for Resistance to Movement, 9th overall in Power, 11th overall in Tension Retention, 13th overall in Durability, and 18th overall in Spin potential. Our playtest team also rated Sonic Pro well above average in a sixth category: Control. These ratings are good enough to put Sonic Pro in the top 20 of our published string playtest reports.
One playtester broke the sample, after two hours of play.
Head Sonic Pro does indeed seem to be best suited for big hitters, given its resistance to movement and durability. Players who prefer thinner strings will appreciate the fact that Sonic Pro’s durability comes not from its gauge but from its construction. Finally, its power level, as noted by our playtesters, might even provide an edge over other poly strings.
“This string has no learning curve. It’s very predictable. I never have to worry about tweaking my swing path, head speed or angle of attack. Full swings can be executed without fear of hitting long, and counter punches tend to find their mark. The control and spin inspire confident tennis.” 5.5 male all-court player using Head i.Tour MP strung at 62 pounds CP (Polyester/Nylon 16)
“This is a fun string to use. A full swing is rewarded with tons of spin and control. The comfort is unbelievable. If you have any worries about getting into polyester, start here.” 3.5 male all-court player using Dunlop 200G 95 (Muscle Weave) strung at 60 pounds LO (Nylon 17)
“Excellent control and great bite. More power than I expected. This string’s spin potential allowed me to achieve safer net clearance. The ball rotation is out of this world.” 5.0 male all-court player using Prince Original Graphite OS strung at 56 pounds LO (Head RIP Control 17)
“This string feels extremely solid at impact. Sound mechanics are rewarded with a refreshing amount of pop. Given the resistance to movement, spin control is a constant. This is definitely a string I would stock and use.” 4.5 male all-court player using Prince O3 Speedport Red strung at 70 pounds CP (Polyester 16L)
“This polyester has remarkable softness and comfort. It is on par with the best polyesters on the market. The playability makes it a good fit for a wide range of stroke styles and ability levels. It performs like a fancy multifilament, but with twice the durability. I’m sold.” 4.0 male baseliner with moderate spin using Head i.S2 MP strung at 55 pounds CP (Wilson Natural 15L)
“This string has no major flaws. It plays like a designer, 2nd generation polyester. The playability is fairly high for the breed, but it is not going to convert those who prefer a softer impact. I suspect that most people will use it to add bite and control to their hybrid. In that capacity, it will perform perfectly.” 4.5 male all-court player using Head i.Radical MP strung at 65 pounds CP (Tecnifibre NRG2 18)
“This comfortable polyester has uniquely controllable power. It seems to hit a very heavy ball without requiring a massive, energy draining swing. Polyester fans looking for some pop are advised to check this out.” 4.0 male all-court player using Wilson Hyper Pro Staff 5.0 Stretch MP strung at 54/52 pounds CP (Luxilon Big Banger Timo 18)
“While the string starts out stiff, it breaks in quickly and becomes quite comfortable. The tension maintenance and resistance to movement are top notch. The high level of control gives it a user-friendly predictability, making nearly every shot easy to execute.” 4.5 male serve-and-volleyer using Wilson Hyper Hammer 2.3 Stretch OS strung at 62 pounds LO (Wilson Sensation 17)
“As one who normally prefers soft strings, this polyester intrigues me. The combination of spin and power adds a nice dimension to my game. I’m able to hit penetrating stokes, loaded with spin, without having to worry about hitting long. I found myself aiming for actual spots as opposed to general areas. This is a very precise control string. Definitely worth a second look.” 5.5 male all-court player using Babolat Pure Control strung at 55 pounds CP (Wilson NXT 16)
“This string resists movement as well as any I’ve tried. It has more comfort and playability than most strings in its class. It is very lively.” 4.5 male all-court player using Wilson T3 MP strung at 61 pounds CP (Gamma Live Wire Professional 17)
“This string is great for powerful strokes and heavy baseline exchanges. The control and comfort are immediately apparent. Kick serves definitely have more kick. The extra zip and bite make this a high-end polyester. ” 4.0 male using Tecnifibre T Feel 305 (16x19) strung at 57 pounds CP (Goson Polylon 17)
“For a polyester, this string has great feel. It’s also very easy on the arm. It seems to bridge the gap between overly soft nylons and harsh polyesters. It’s a great option for nylon users looking for a more durable string.” 5.0 male all-court player using Head Flexpoint Prestige Mid strung at 54 pounds LO (Head Synthetic Gut PPS 16)
“During installation, I was convinced that this was going to play very stiff. I was pleasantly surprised. This is an extremely comfortable, very playable string. The spin is even better than its gauge would indicate. The touch far surpasses my expectations.” 5.5 male all-court player using K Six One Team strung at 60 pounds CP (Luxilon Big Banger Timo/Nylon 18/17)
“If you are looking for control, look no further. This string will provide welcome relief to over hitters. The control, power and spin are amazing.” 4.0 male all-court player using Head i.X6 OS strung at 62 pounds LO (Tecnifibre X-One Biphase 17)
“Based on the incredible touch and comfort, I have to keep reminding myself that this is a polyester. This string lacks the boardy feel and harsh off-center feedback typical of stiff strings. It not only has delicate touch, but crisp power on volleys. While the tension maintenance and resistance to movement are impressive, the soft, powerful response will make this a very popular string.” 5.0 male all-court player using Prince O3 Hybrid Tour (16x18) strung at 55/57 pounds LO (Prince Synthetic Gut w/Duraflex 16)
“This is a comfortable, resilient polyester with nice power and great control. Pre-stretching is advised. ” 5.0 male all-court player using Head FXP Prestige Team strung at 58 pounds LO (Polyester/Nylon 18/16)
“This string is comfortable and powerful from the first hit. Serves definitely have extra pop, while volleys have decidedly average control. After 18 hours, there is no sign of wear.” 4.0 male all-court player using Head Flexpoint Radical MP strung at 62 pounds CP (Luxilon Big Banger Alu Power Rough 16L)
“This is an above average polyester with great control. The bite and spin are excellent. The playability and touch are unspectacular, making this more of a heavy hitting groundstroke tool.” 5.0 male all-court player using KSix One (68 Holes) strung at 56 pounds CP (Wilson Ultra Synthetic Gut 16)
“This is the most comfortable polyester I’ve ever used. Control, spin and playability are average. There is very little harsh feedback. This is recommended to string breakers in search of comfort.” 5.0 male all-court player using Head i.S12 strung at 63 pounds LO (Nylon Monofilament 16)
“This string is quite stiff and boardy. Comfort, touch and feel are not up to my multifilament standards. The tension maintenance and lack of string movement are impressive. This is a good string for big hitters with durability concerns, but it’s too stiff for me.” 4.5 male all-court player using Babolat Aeropro Drive strung at 57 pounds LO (Gamma Live Wire Professional 17)
“This is a solid overall string. It is a little hard on the arm and is probably aimed at power baseliners. Very durable with good tension maintenance. Recommended to those looking for durability and power.” 5.0 male all-court player using Babolat Pure Drive Roddick + strung at 58 pounds LO (Gamma Live Wire Professional 16)
“Surprisingly comfortable for a stiff handling string. Control is spot-on. As someone who prefers the resilience of a multifilament nylon, however, this tends to punish slower strokes with a dead hit. This would work well in a hybrid with soft cross.” 4.5 male serve-and-volleyer using Wilson nTour strung at 58 pounds CP (Wilson NXT 16)
“This string is more responsive than other polyesters I’ve tried. It has decent bite on slices and serves. The high power level might cause some control issues for flatter stroke styles.” 5.0 male all-court player using Volkl Tour 10 MP strung at 55 pounds LO (Forten Thin Blend 18)
“As a counter-puncher, I find this string underpowered from the baseline. Control suffers because of too many stroke alterations. The durability, however, is excellent, and volleys are very precise and easily placed.” 4.5 male all-court player using Head Liquidmetal Radical OS strung at 60 pounds LO (Gamma TNT2 17)
“This is a soft polyester with very good spin and control. Feel is great, but it gets a little mushy after 7 hours.” 4.0 male all-court player using Prince O3 Tour MS strung at 58 pounds CP (Luxilon Big Banger Alu Power Rough 16L)
“Excellent durability. Those with control issues should string it a little tighter than usual. I find it slightly more “trampoliney” and less predictable than other polyesters.” 4.5 male all-court player using Wilson Hyper Hammer 6.2 strung at 62 pounds CP (Gamma Synthetic Gut w/Wearguard 15L )
“Very crisp response but a little tough on the arm. Recommended for heavy frames and big hitters. Hard to judge fully, though, because it broke after 2 hours.” 5.0 male all-court player using Wilson nTour strung at 58 pounds LO (Polyester/Nylon Multifilament 16)
“Easy to string for a poly. Comfort and playability are high for this breed, but still a little too firm for me. This would be a great main in a hybrid.” 4.0 male all-court player using Wilson Hyper Pro Staff 5.1 Surge strung at 58 pounds CP (Yonex Tour Super 850 Pro 16)
“This string has great spin and control, but it is a little too stiff for me. It would be much better in a hybrid.” 3.0 male all-court player using Volkl DNX V1 MP strung at 56 pounds LO (Gamma Live Wire Professional 17)
“The high power level requires some adjustments. This string definitely plays like a bouncy, multifilament and it should be strung accordingly. It is recommended to players looking for a durability string with comfort and tons of zip.” 5.0 male all-court player using KSix One strung at 60 pounds CP (Wilson Sensation 16)
“This is clearly a durability string. It is slightly lacking in feel and touch. Spin and control are less than you would expect for this type of string. If you’re looking for a durability string with power, this is a good option.” 4.5 male all-court player using Pro Kennex Kinetic Pro 5g strung at 55 pounds LO (Gamma Live Wire XP 17)
“Typical of most polys, this string has low comfrort and high durability. With every swing, I am surprised by the amount of pop. This is not for finesse players.” 6.0 male all-court player using Prince O3 White strung at 58 pounds CP (Wilson Sensation 16)
“This is a durability string that plays stiff. Tension maintenance and resistance to movement are exceptional. Power is average, but control suffered due to lack of feel.” 5.0 male all-court player using Head Liquidmetal Prestige Mid strung at 58 pounds LO (Prince Synthetic Gut w/Duraflex 16)
“Incredible spin, but not as much feel as I prefer. As someone who relies on feedback, this string makes it hard for me to judge how the ball is coming off the string bed. Touch shots suffer because I cannot get a feel for how hard to swing. Those who prefer a crisp, muted response will like this string.” 5.0 male all-court player using Prince O3 Red strung at 58 pounds CP (Wilson Natural Gut 16)
“Hard to generate power. The feel is lacking and touch shots are tough to gauge.” 5.0 male all-court player using Head FXP Radical Team (Flexpoint) strung at 60 pounds LO (Prince Synthetic Gut w/Duraflex 16)
“This is a “spongy” string. Therefore, control and feel suffer. I recommend stringing it on the tight end. Spin and touch shots are tough to execute because of the unpredictable trajectory.” 4.0 male all-court player using Wilson nSix One (68 Holes) strung at 60 pounds LO (Natural Gut/Polyester 17/18)
“Another poly string with few discernible qualities. I have yet to find a member of the poly family that has adequate comfort and playability. Slower strokes produce little more than a dead hit. This is a niche string for big hitters in search of durability.” 4.5 male all-court player using Volkl DNX 1 w/Power Arm strung at 55/53 pounds CP (Forten Dynamix 16)
(Strings normally used by testers are indicated in parentheses.)
|EASE OF STRINGING
(compared to other strings)
|Number of testers who said it was:|
|about as easy||16|
|not quite as easy||18|
|not nearly as easy||2|
(compared to string played most often)
|Number of testers who said it was:|
|about as playable||8|
|not quite as playable||18|
|not nearly as playable||4|
(compared to other strings of similar gauge)
|Number of testers who said it was:|
|about as durable||16|
|not quite as durable||1|
|not nearly as durable||0|
|From 1 to 5 (best)|
|Resistance to Movement||4.0|
See all articles by Greg Raven
About the Author
Greg Raven is an associate editor for RSI magazine and technical writer. He is certified as a Master Racquet Technician by the U.S. Racquet Stringers Association. He can be reached via e-mail at firstname.lastname@example.org, or through Facebook, LinkedIn, and Twitter. He plays tennis five days a week, and is turning into an avid cyclist.
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