How to optimise helmet acoustic properties?
This certainly is another interesting topic that has often been the subject of heated discussions between motorcyclists! Let’s start by clarifying a few points. All racing helmets are necessarily noisier than sport-touring helmets because they feature various air vents to ensure the right level of ventilation even in most intense usage conditions. Furthermore, speed is a factor that affects significantly the noise level, since the turbulence that forms around the helmet is directly proportional to the forward movement speed.
So, if you expect your top-of-the-range racing helmet to be noise-free at very high speeds (but don’t forget about the Highway Code!) you may be asking too much… Having clarified this different approach to the concept of noise, let’s move on and try to understand if there are variables we can act upon to limit it.
The type of motorcycle can actually determine a greater or lower turbulence on the helmet, thus affecting the noise you perceive. Naked motorcycles almost entirely expose motorcyclists to air, contrary to a maxi enduro, which may even feature an oversized windshield. Also, the posture while driving impacts the noise, since the position of the head determines a different coefficient of aerodynamic resistance. The same applies to the motorcyclist’s height.
As a matter of fact, the taller we are the more we stick out from that sort of aerodynamic “bubble” that forms while the motorcycle moves. The build of a motorcyclist can also affect the level of turbulence around the helmet. The shape and size of your face can have an effect as well. A sharper face in an M size helmet compared to a rounder face in the same size helmet could be exposed to a greater noise level because there is more space where turbulence may form, and also because it may not entirely adhere to the inner padding.
We’ll conclude by saying that, once you’ve identified the right helmet for you, as well as your motorcycle and your driving style, some simple adjustments may reduce the noise perceived and improve your driving experience, like mounting an aftermarket front fairing, purchasing an oversized windshield or simply remembering to use the Stop Wind (where provided) and a neckerchief. Great awareness of your posture on the motorcycle may give you some extra help to curb noise!