In the late 1970s Elmer Carlson, an engineer at Knowles Electronics, developed what we now call Musicians Earplugs. His design replicated the natural response of the ear canal so that sound heard with these earplugs would have the same quality as the original, just quieter. In 1985, while consulting with the Chicago Symphony Orchestra, Mead Killion, Ph.D., president and founder of Etymotic Research, concluded that there was a real need for Carlson's earplugs. The resulting "Musicians Earplugs," were introduced later that year.

Musicians Earplugs are the highest fidelity earplugs available in the world today. Their accurate real-ear response is achieved by combining Etymotic's patented attenuator buttons with custom earmolds. The buttons have a diaphragm which functions as an acoustic compliance, while the volume of air in the sound bore of the earmolds 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.

Etymotic Research, Inc. is the sole manufacturer of the Musicians Earplug filter buttons. Etymotic tests all attenuator buttons for proper resistance and compliance values before they are shipped to the earmold labs. To ensure the acoustic integrity of finished Musicians Earplugs, each authorized earmold laboratory uses an acoustic mass meter to verify that the earmolds have the correct volume of air in the sound bore to produce flat attenuation when the buttons are in place.