# Fletcher-Munson curve We're most sensitive to 3.5kHz. This is the resonant frequency of the ear canal.[^1] This is also approximately the frequency of a baby's cry.[^2] In music school, I learned this is about where the singer's formant is. We're most sensitive to 1-5kHz. This is where consonants live. As the reference level flattens, we hear frequencies fairly evenly.[^1] The curves show us that if 1kHz is played at 20dBSPL, 100Hz would have to be played at 50dBSPL. [^1]: [AV Genius "How to Mix" series - The Fletcher Munson Curve](https://www.youtube.com/watch?v=dGQh5bwm_8s&list=PL1sNd-gBgKcokKS0v14HYieHxmHsQS38V&index=3) [^2]: [[Mixing Audio—Concepts, Practices, and Tools]] pg. 14