Schematic side view of the ER•15 C = compliance L = inductance R = resistance

What Makes Musicians Earplugs High Fidelity?
Musicians Earplugs replicate the natural response of the ear canal so that sound heard with these earplugs has the same quality as the original, just quieter.

ER•15
ER•15 buttons have a diaphragm which functions as an acoustic compliance, while the volume of air in the sound bore of the custom earmold acts as an acoustic mass. The combination of the two produces a resonance at approximately 2700 Hz (as in the normal ear), which results in a smooth, flat attenuation.

ER•9
The ER•9 has reduced diaphragm stiffness for less attenuation.

ER•25
The ER•25 has an increased diaphragm stiffness and an acoustic-mass channel molded into the button for more attenuation.

Open ear response of the average ear measured in a diffuse field or reverberant room. The response of the ER•15 Musicians Earplug indicates a 15 dB reduction in eardrum sound pressure at each frequency.