Braun Series 9 9517s PRO+ Review: The Ultimate Shaving Experience, Redefined

The quest for a smooth, clean-shaven face is a ritual nearly as old as humanity itself. Our ancestors, tens of thousands of years ago, used sharpened flint and obsidian to scrape away facial hair. Ancient Egyptians elevated this to an art form with bronze razors, viewing a clean face as a mark of civilization and purity. From Roman tonsores to the revolutionary safety razor of the early 20th century, the goal has remained constant: to win the daily battle against our own biology. But why is this seemingly simple task so challenging? And how has modern science transformed it from a risky chore into a sophisticated, comfortable experience?

To understand the marvel of a modern electric razor like the Braun Series 9 9517s PRO+, we must first appreciate the adversary: the human beard. It is a complex landscape of remarkable resilience.

The Whisker’s Challenge: A Biological Battlefield

Facial hair, or keratin, is deceptively tough. An individual whisker has a tensile strength comparable to that of a copper wire of the same thickness. This hair doesn’t grow in a neat, uniform direction. Instead, it sprouts at a variety of angles, creating a chaotic terrain. Furthermore, the density and thickness of this growth vary dramatically across the face—denser and coarser on the chin and upper lip, sparser and finer on the cheeks.

This combination of toughness, multi-directional growth, and inconsistent density presents a formidable engineering problem. A successful shave requires a tool that can cut cleanly through this resilient material without pulling, snagging, or irritating the delicate skin surface just micrometers away. This is where the divergence in shaving philosophy begins, leading us to the two primary modern approaches: manual and electric. While manual razors offer closeness at the cost of potential nicks and recurring blade purchases, electric razors represent a different path—a path paved by advanced engineering, culminating in two dominant designs: rotary and foil.

Rotary shavers use spinning circular blades, which excel at tackling longer stubble growing in various directions. Foil shavers, the category to which the Braun Series 9 belongs, employ a fundamentally different mechanism. They utilize a bank of oscillating blades moving at high speed beneath a thin, perforated metal sheet—the foil. This foil acts as a protective barrier for the skin while capturing hairs in its intricate patterns, guiding them towards the cutting elements. For many, especially those with sensitive skin, the linear cutting motion and protective nature of a foil shaver offer a superior balance of closeness and comfort.

Deconstructing a Modern Marvel: Inside the Series 9 PRO+

To truly appreciate the leap from sharpened flint to a device like the Series 9 PRO+, we need to look under the hood. It’s not just a single tool but a symphony of coordinated technologies, each designed to solve a specific aspect of the biological challenge.

The Cutting Collective: More Than Just Blades

At the heart of the 9517s are its 5 Pro Shave Elements. This isn’t just about having more blades; it’s about mechanical synergy. Each element has a specialized role. For instance, the central ProLift Trimmer is designed specifically to lift and cut flat-lying hairs—often the most difficult to capture. Other foils are engineered with unique patterns, like Braun’s OptiFoil™, to catch hairs of different lengths and growth directions.

The materials themselves are a testament to modern science. The trimmers are honed from surgical-grade steel, a term that signifies a specific type of stainless steel (like 316L) known for its high strength, exceptional corrosion resistance, and biocompatibility, minimizing the risk of skin reactions. One of the cutting elements is further enhanced with a titanium coating. In industrial applications, thin coatings like Titanium Nitride (TiN) are applied via Physical Vapor Deposition (PVD) to dramatically increase surface hardness and reduce the coefficient of friction. For a shaver, this translates to a blade that stays sharper for longer and glides more effortlessly across the skin.

The Physics of Comfort: The Power of Vibration

Perhaps the most fascinating technology at play is Braun’s Sonic Technology, which generates 10,000 micro-vibrations per minute. This isn’t a gimmick; it’s applied physics. These vibrations serve two crucial purposes.

First, they create a cushioning effect that reduces friction. In the field of tribology (the science of friction, wear, and lubrication), this phenomenon helps to momentarily lift the shaver head on a microscopic cushion of air and skin, allowing it to glide rather than drag. This dramatically reduces the potential for redness and irritation.

Second, the vibrations cause the tiny hairs to oscillate and stand more upright, making them easier for the foils to capture and the blades to cut cleanly on the first pass. Imagine trying to mow a lawn where half the grass is lying flat versus a lawn where it’s all standing tall. The vibrations effectively “comb” the stubble for a more efficient and effective cut, reducing the need for multiple passes over the same area.

The Intelligent Edge: A Shaver That Thinks

Beard density is not uniform, so why should a shaver’s power be? This is the logic behind SyncroSonic technology. This is, in essence, a simple and effective closed-loop control system. A sensor within the shaver’s motor constantly measures the resistance, or load. When the shaver moves from a less dense area like the cheek to a thicker patch on the chin, the motor encounters more resistance. The onboard microchip detects this change instantly and signals the motor to increase power. Conversely, it throttles back in sparser areas. This is analogous to a modern car’s cruise control system automatically applying more gas to maintain speed while going uphill. The result is an adaptive shave that delivers optimal power precisely when and where it’s needed, maximizing both efficiency and comfort.

The Unseen Engine: Power and Endurance

The cordless freedom of the Series 9 PRO+ is powered by a Lithium-Ion (Li-Ion) battery. This is the same battery technology that powers our smartphones and electric cars, and its advantages over older Nickel-Cadmium (NiCd) or Nickel-Metal Hydride (NiMH) batteries are immense. Li-Ion batteries offer higher energy density (more power in a smaller, lighter package), they don’t suffer from the “memory effect” that plagued older rechargeables, and they can be charged much more quickly. The 60-minute runtime and 5-minute quick charge option for a single shave are direct benefits of this superior battery chemistry, managed by an internal Battery Management System (BMS) that ensures safety and longevity.

Beyond the Cut: Technology as Skincare

Ultimately, the goal of all this advanced engineering is not just to remove hair, but to do so while protecting the skin. The ability to use the razor wet or dry, for example, is a direct benefit for skin health. Using foam or gel introduces a layer of lubrication that further reduces friction and soothes the skin. The 100% waterproof design, achieved through meticulous engineering with rubber gaskets and sealed components (to standards like IPX7), makes this possible and simplifies cleaning.

Each technological element—from the smooth-gliding titanium coating to the friction-reducing sonic vibrations and the irritation-preventing adaptive power—converges on a single goal: to minimize the stress on the skin. By reducing the number of passes required, preventing pulling, and ensuring a clean cut, the technology actively works to prevent common issues like razor burn and the inflammation that can lead to ingrown hairs.

The journey from a piece of flint to the Braun Series 9 PRO+ is a microcosm of human innovation. It shows our relentless drive to apply principles of physics, materials science, and intelligent engineering to solve a deeply personal, everyday problem. This device is more than just a tool; it’s a pocket-sized laboratory, a testament to the idea that even the most routine aspects of our lives can be a platform for extraordinary science. And as we look to a future of AI-driven personalization and even smarter materials, one thing is clear: the quest for the perfect shave is far from over. It’s only getting sharper.