How We Test
Multi-faceted testing helps us develop the most effective wind noise reduction products.
We road test in two ways. The first is riding with the product at one ear and without at the other ear. The rides are performed at various speeds. We then summarize the impressions. The second is to instrument cyclists with special in-canal microphones, record wind noise at known speeds (i.e. extracting actual Garmin data), and then calculate the sound pressure level reductions. Our experience shows that while our audio measurements cannot predict exactly how much wind noise reduction a cyclist will experience, they do provide reasonable expectations.
For road testing, we use special probe microphones for accurate in-ear measurements - similar to those used by audiologists. The tip of the probe tube is placed approximately five millimeters from the eardrum. This is the most accurate way to measure wind noise. We have read about people measuring wind noise by placing a microphone at the center of the outer ear. Anyone who has held a microphone in the wind or blown on one knows that they are susceptible to small air pressure fluctuations, causing inaccurate wind noise measurements.
However, instrumented road testing is not without its challenges. Wind direction and wind turbulence levels can change rapidly, and the exact orientation of a cyclist's head can be difficult to control. Because of these issues, we augment our road testing with aeroacoustic testing performed under controlled laboratory conditions.
Wind Tunnel Testing
Most wind tunnels are designed for evaluating aerodynamic effects like drag and are noisy. Aeroacoustic testing requires extensive noise suppression, and these quiet wind tunnels are rare, specialized, and expensive. Cat-Ears designed and built special open jet wind tunnels. With careful attention to sound and vibration damping, they are remarkably quiet for the volume of air moved. In addition, we developed custom aeroacoustic test heads.
We test using multiple helmet brands (Bell, Giro, Bontrager, Rudy, etc.) and retail price points. We also test using different types of eyewear. Different helmets and eyewear combinations can influence the amount of wind noise.
Flow Visualization + Audio
Audio / Performance Analysis
We utilize Sigview professional signal analysis software to evaluate and compare road and wind tunnel audio files.
Multi-faceted testing helps us develop the most effective products.