What is the difference between SNR and NRR, and how do they impact the effectiveness of hearing protection devices?

SNR (Single Number Rating) measures the overall noise reduction of a hearing protection device across all frequencies, while NRR (Noise Reduction Rating) measures the device's noise reduction specifically at mid-frequency levels. SNR provides a more accurate representation of a device's effectiveness across different frequencies, while NRR may not be as comprehensive. Both ratings impact the effectiveness of hearing protection devices by indicating how much noise they can reduce, helping users choose the most suitable option for their needs.