String comparison
Sonic Pro vs Black Code
Head Sonic Pro against Tecnifibre Black Code: ratings, specs and which one fits your junior.
The short answer
Both are polyester strings. Black Code leads on spin, durability and tension hold. They score the same for arm friendliness (3/5). Sonic Pro costs less per set.
Ratings
Power
Spin
Control
Comfort
Durability
Tension hold
Ratings are on a 1–10 scale. The higher score is in bold when they differ.
Pick Sonic Pro if…
- You want to spend less (from $8 vs $12 a set)
- Best for: budget-conscious players wanting poly
- Best for: club players in regular competition
- Best for: those wanting all-round playability
Pick Black Code if…
- You want more spin (8 vs 6 out of 10)
- You want more durability (8 vs 6 out of 10)
- You want more tension hold (6 vs 5 out of 10)
- Best for: aggressive baseliners who control points with heavy spin
- Best for: players wanting shaped poly comfort
- Best for: big hitters who swing hard
Specs side by side
| Spec | Sonic Pro | Black Code |
|---|---|---|
| Type | Polyester | Polyester |
| Construction | Unique co-polymer polyester with soft molecular construction | Pentagonal co-polyester with Thermocore technology |
| Gauges | 16, 17 | 16, 17, 18 |
| Stiffness | Medium | Medium |
| Set price | $8–12 | $12–16 |
| Reel price | $90–120 | $130–160 |
| Arm friendliness | 3/5 · Moderate | 3/5 · Moderate |
| Cost to maintain | 5/5 | 4/5 |
| Recommended from | Age 13 | Age 13 |
| Levels | Intermediate, Advanced | Intermediate, Advanced |
| Play styles | All court, Baseliner | Baseliner, Big hitter |
| Junior tension | 50-54 lbs for juniors. Best in mid-50s. | 48-52 lbs for juniors. |
Sonic Pro in short
Head Sonic Pro combines unique co-polymer polyester with a soft molecular construction for good touch and comfortable feel. "A great all-round string that delivers on its promise of control and comfort." Received remarkably low stiffness scores compared to most polys tested. Power level slightly higher than average for a co-poly. After an hour of hitting it softens up and feels livelier. Best in the mid-50s tension range - at higher tensions it plays too dead, lower tensions lose control. Budget-friendly at $8-12 per set.
Black Code in short
Tecnifibre Black Code is a co-poly with pentagonal profile for spin and Thermocore technology for comfort. "Dangerous in the hands of an aggressive baseliner who likes to control the point with heavy spin." The 5-sided profile provides powerful snapback for spin generation while Thermocore uses heating and cooling phases to soften the string. Playtesters found it "soft, plush and very comfortable for a polyester string" with muted impact feel that doesn't send jarring vibrations on off-center hits. Great value shaped poly.
Sonic Pro vs Black Code: quick answers
Which has more spin, Sonic Pro or Black Code?
Tecnifibre Black Code, with a spin rating of 8/10 against 6/10.
Which is more arm-friendly for a junior?
They score the same, 3/5. Sonic Pro is recommended from age 13 and Black Code from age 13.
Which lasts longer?
Tecnifibre Black Code rates 8/10 for durability against 6/10.
Which is cheaper?
Sonic Pro costs about $8–12 a set and Black Code about $12–16, at typical retail.
The short answer and the "pick if" lists are generated from our ratings and junior data only. Data verified 2025-01 (Sonic Pro) and 2025-01 (Black Code).