Playtest: Head Sonic Pro Edge
By Greg Raven
Sonic Pro Edge is a new version of the well-known Sonic Pro from Head, the most obvious difference being that Sonic Pro Edge is a five-sided geometric monofilament, where Sonic Pro is a more traditional cylindrical monofilament.
In addition to its pentagonal cross-section, Sonic Pro Edge features uniquely processed co-polymer polyester, which is a specially-formulated combination of resins and fibers. According to Head, Sonic Pro Edge offers maximum spin and control, increased power for a polyester string, exceptional touch and feel, and increased durability.
Sonic Pro Edge is designed for players looking to create extra spin and control with polyester.
Sonic Pro Edge is available in 16-gauge only in anthracite. 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. Be sure to read the conclusion for more information about your free set.
In the lab
We tested the 16-gauge Sonic Pro Edge. The coil measured 40 feet. The diameter measured 1.28-1.33 mm prior to stringing, and 1.25-1.27 mm after stringing. We recorded a string bed stiffness of 73 RDC units immediately after stringing at 60 pounds in a Wilson Pro Staff 6.1 95 (16 x 18 pattern) on a constant-pull machine.
After 24 hours (no playing), string bed stiffness measured 67 RDC units, representing an 8 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 Edge added 16 grams to the weight of our unstrung frame.
The string was tested for five weeks by 36 USRSA play testers, with NTRP ratings from 3.5 to 6.0. These are blind tests, with play testers receiving unmarked strings in unmarked packages. Average number of hours play tested was 24.6.
Installing Sonic Pro Edge is a little different from installing most other polyester strings. We did note that some of the edges on the mains became worn during the installation of the crosses, but this is normal for geometrics that have well-defined apexes between the facets.
One playtester broke his sample during stringing, 10 reported problems with coil memory, four reported problems tying knots, and four reported friction burn.
On the court
Even before we had all the results to tabulate, the positive comments by members of the playtest team gave notice that there was something special about this string. Once all the results were in, they echoed the other feedback we received: Sonic Pro Edge is a winner.
Of the 168 strings we’ve playtested to date for publication, Sonic Pro Edge tied for second for Control, placed fourth overall for Spin Potential, came in 14th overall in Durability, and placed 20th overall in Resistance to Movement. That’s four top-20 finishes for a co-polyester string.
“Tied for second for Control” is plenty impressive, but wait until you hear the details. The other string with the same score is a premium multifilament, and the number one string in this category is a premium natural gut product. Did we mention that Sonic Pro Edge is a co-polyester string?
It seems almost anticlimactic to mention that Sonic Pro Edge also garnered excellent scores in Tension Retention and Power, and well-above-average scores in Playability, Comfort, and Touch/Feel.
Overall, Sonic Pro Edge is the third-highest-scoring string we’ve ever playtested.
Four of the playtesters broke the sample during the playtest period, one each at 6, 8, 14, and 25 hours.
As of now, three of the top-four strings we have playtested are polyester-based. While it may be comforting to traditionalists to see that natural gut is firmly ensconced at the top of this short list, it is clear that manufacturers such as Head have made tremendous strides in the design of polyester strings, with Sonic Pro Edge being the most recent impressive example.
Head is so confident the USRSA members will like Sonic Pro Edge that it is including a free sample set with this magazine for all USRSA members in the United States.
“This is comfortable for a monofilament, with excellent control. It might be time to switch to polyester.” 4.0 male all court player using Prince EXO3 Red strung at 48 pounds CP (Gamma TNT2 Pro Plus 17L)
“This is a soft poly with no downsides. It has great spin, control, and power. It is very durable without trading away much playability. Spin artists look no further!” 3.5 male baseliner with moderate spin using Prince Thunder Rip OS strung at 58 pounds LO (Tourna Big Hitter Blue Rough 17)
“Solid all-around performance. Excels in every area. This string is definitely playable enough to be used as a full set.” 4.5 male all court player using Prince EXO3 Tour (18x20) strung at 54/57 pounds LO (Prince Lightning XX 16)
“This is a comfortable string! Compared to other polys, it has good power. Given the very predictable and solid-feeling response, I find myself wanting to play with it more than other strings. It lasted twenty five hours without a noticeable loss in playability!” 4.5 male serve-and-volley player using Wilson K Three strung at 57 pounds LO (Babolat RPM Blast 16)
“Great spin, power, and feel without sacrificing any control. I can take full cuts without worrying about the ball sailing unpredictably. This is a must try for players who like to hit with power and spin.” 4.0 male all court player using Wilson BLX Six One (16x18) strung at 53 pounds CP (Genesis Typhoon 16)
“This is a soft co-poly with a very precise response. The sharp edges bite into the ball and create great spin. This string definitely goes in my ‘top ten’ list.” 5.5 male baseliner with heavy spin using Vortex ES 100 strung at 52 pounds CP (Spintex Exclusive HD 16)
“Where have you been hiding this one? This is a control string that manages to have great touch. It performs well at slow and fast swing speeds. It has spin, power, and feel. Every now and again you play with a string that separates itself from the pack. This is that string.” 5.0 male all court player using Wilson BLX Six One Team strung at 50 pounds LO (Prince Synthetic Gut w/Duraflex/Luxilon Savage 16/16)
“This is the perfect string for those in search of more spin. It’s one of the best geometric polys I’ve hit. Power and spin come effortlessly. My hitting partners have commented on the heaviness of my shots. Serves are not quite as powerful, but spin is excellent. This could become my new ‘go-to’ string.” 4.5 male baseliner with heavy spin using Yonex RDS 002 Tour strung at 50 pounds CP (Topspin Cyber Twirl 16L)
“I keep waiting for this string to lose tension and playability, but it will not die. Given how stiff it handles, the feel is quite soft. The durability and tension maintenance are among the best I’ve experienced.” 6.0 male all court player using Wilson BLX Steam strung at 56 pounds LO (Luxilon M2 Pro 16L)
“Like the top polyesters, this string has phenomenal spin and control. It isn’t just for baseliners with heavy top; it has the comfort and playability to work across ability levels and stroke styles. I recommend it to just about anyone looking for more control and spin.” 5.0 male all court player using Head Youtek IG Prestige Mid strung at 50 pounds LO (Solinco Tour Bite 16L)
“This is the best string I’ve tested. It has the control, spin and durability of a poly, but somehow manages to have the soft response of a multi. It gives me confidence to swing big from the baseline. It’s tad stiff off-center, but not as bad as most polys.” 5.0 male all court player using Head Youtek Speed MP 315 (16x19) strung at 54 pounds LO (Luxilon TiMO/Wilson NXT 18/17)
“This is a very crisp string with excellent touch, feel, and control. Tension maintenance is exceptional. I could get away with lowering the tension even more.” 4.0 male baseliner with moderate spin using Dunlop Biomimetic 600 Lite strung at 56 pounds LO (Wilson Sensation 17)
“I love playing with this string! It gives me more power on serves along with crisp volleys and good bite. I typically avoid polyester because it is too stuff, but this string has changed my mind. It has great feel. My touch volleys are simply better with this string.” 4.0 male all court player using Babolat AeroPro Drive Cortex strung at 62 pounds CP (Wilson Sensation Control 16)
“This is a crisp poly with good power and control. With its sharp edges, the spin potential is great. Very little string movement.” 4.5 male all court player using Wilson Pro Staff 6.1 strung at 50 pounds CP (Ashaway Dynamite 17)
“This should appeal to players who favor the softer feel of nylon or synthetic gut.” 4.5 male all court player using Volkl Boris Becker 10 strung at 60 pounds CP (Gamma Synthetic Gut 16)
“Even at low tensions, this one strings up firm. After a short break-in period, playability improves. It seems designed to appeal to players who prefer Babolat RPM Blast or Technifibre Black Code.” 5.0 male all court player using Babolat AeroPro Drive GT strung at 53 pounds CP (Tecnifibre Black Code/Babolat VS Touch 17/16)
“Very precise response. It holds up quite well over time. High marks for comfort.” 4.5 male all court player using Wilson BLX Six One Tour strung at 45 pounds LO (Luxilon Alu Power/Wilson NXT Tour 16L/16)
“Impressive comfort and feel. Best suited to big hitters who make their own power but could use a softer, more playable poly.” 5.0 male all court player using Head MicroGEL Extreme Team OS strung at 57 pounds LO (Head Sonic Pro 16)
“Great spin. Not as stiff as most polyesters.” 4.5 male all court player using Babolat Pure Drive GT strung at 56 pounds LO (Babolat RPM Blast 17)
“This is a good option for those who want a durable string that does not skimp on playability and power. Similar to many Luxilon strings, this gives you excellent pop and bite. The feel and touch are above average for the breed.” 5.0 male serve-and-volley player using Wilson BLX Pro Staff Six One strung at 58/55 pounds LO (Wilson NXT 17)
“This is a solid poly with excellent spin. The feel is fairly comfortable. I bet it would work great in a hybrid too.” 4.0 male baseliner with heavy spin using Yonex V Core strung at 52 pounds LO (Gamma TNT2 16)
“For a shaped poly, installation is quick and painless. This string provides superb spin and fantastic feedback. The lack of power makes it ideal for players who generate their own pace. Touch is above average.” 5.5 male baseliner with heavy spin using Wilson BLX Pro Open strung at 58.5 pounds LO (Luxilon Alu Power 16L)
“This is actually one of the few monofilaments that I’d recommend in a full bed. The fact that it provides more spin than other polys is a nice bonus.” 4.0 male baseliner with heavy spin using Dunlop 200G (Muscle Weave) strung at 52 pounds CP (Prince Synthetic Gut w/Duraflex 16)
“Great spin and control with above average playability and power. Good stuff!” 3.5 male all court player using Head Youtek Star Five strung at 50 pounds CP (Solid Core Nylon 16)
“I typically play with a softer string, but this poly has truly piqued my interest. Despite having flat strokes, I find myself hitting with more spin. This is a very playable, arm-friendly poly.” 5.0 male all court player using Wilson BLX Blade strung at 54 pounds LO (Wilson SGX 16)
“The shaped profile provides great bite. Though I’m impressed with the durability, tension maintenance and resistance to movement, the comfort and feel are not quite on par with a nylon multifiliment. This is definitely a string that would suit players looking for the ideal combination of durability, spin, and playability.” 4.5 male all court player using Prince O3 Blue strung at 55 pounds LO (Gamma Professional 17)
“Above average tension maintenance and decent comfort. Recommended to poly players who want a slightly softer ride with a more user-friendly feel.” 5.0 male all court player using Wilson Juice 100 strung at 55/58 pounds CP (Luxilon Savage/Wilson Sensation 17/17)
“This is a durable string with low tension loss. Great for string breakers, but a little stiff for my taste. Recommended to big hitters who want a little more milage from their string bed.” 5.0 male all court player using Prince EXO3 Tour (16x18) strung at 60 pounds LO (Multifilament Nylon 17)
“What I gain in control from the baseline, I lose in feel at the net. Though I have some additional spin on the forehand, the string doesn’t provide enough directional control. I have to swing too hard to achieve depth, which is a recipe for a sore arm.” 4.0 male all court player using Volkl Power Bridge 4 strung at 55 pounds CP (Volkl V Twist 17)
“Decent playability, power, and comfort for a firm-handling string.” 4.5 male all court player using Babolat Pure Drive Roddick GT strung at 40 pounds LO (Babolat RPM Blast 16)
“This poly plays stiff and boardy for the first three hours, after which the liveliness, spin, and comfort emerge. I’ll stick with my typical set-up because I don’t like the initial break-in period.” 4.0 male all court player using Wilson BLX Steam strung at 52 pounds CP (Luxilon Alu Power 16L)
“A great option for players who like to swing big. Finesse players or those with compact strokes may find it too jarring on the arm. Not bad for string breakers though.” 4.0 female all court player using Prince O3 Tour MP strung at 48 pounds CP (Tecnifibre NRG2 16)
“Like most polys, this one has excellent spin and durability. The comfort is not on par with a nylon multifilament. Recommended to baseliners with extreme grips.” 5.5 male all court player using Vantage VT002 Black strung at 52 pounds LO (Gamma Professional 17)
“This one feels great right off the stringer. After 3 hours, however, the tension starts to drop and there is more vibration.” 4.5 male all court player using Babolat AeroPro Team GT strung at 57 pounds CP (Babolat Xcel 17)
“Plays lively and comfortable for the first couple of sessions. After that, however, there is a buzzing sound and it feels somewhat dead.” 4.5 male serve-and-volley player using Babolat Pure Drive strung at 58 pounds CP (Gamma TNT2 Touch 16)
“This string loses tension and resilience pretty quickly. I experienced a little elbow pain, which went away when I switched back to my typical set-up.” 4.5 male all court player using Solinco Tour 8 strung at 45 pounds CP (Solinco Tour Bite 19)
(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||21|
|not quite as easy||11|
|not nearly as easy||0|
| OVERALL PLAYABILITY
(compared to string played most often)
|Number of testers who said it was:|
|about as playable||10|
|not quite as playable||12|
|not nearly as playable||3|
| OVERALL DURABILITY
(compared to other strings of similar gauge)
|Number of testers who said it was:|
|about as durable||18|
|not quite as durable||1|
|not nearly as durable||0|
|From 1 to 5 (best)|
|Durability (14th overall)||4.4|
|Control (2nd tie)||4.0|
|Spin Potential (4th overall)||4.1|
|Resistance to Movement (20th overall)||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.