The SensGard acoustic chamber seals at the outside of the ear canal. When this happens, the ear canal and the chamber effectively become one long tube — from the inner ear all the way out to the end of the SensGard device.

When sound energy reaches your ear, it naturally follows the path of least resistance. Because the acoustic chamber has a much larger air volume than the ear canal, sound energy is drawn into the chamber instead of into the ear.

Once inside the chamber, three things happen:

1. The sound waves are dampened by acoustic foam

The foam absorbs part of the incoming energy, reducing the intensity of the sound.

2. The remaining sound waves refract off the chamber wall

As the waves hit the top of the chamber, they bend and change direction.

3. The refracted waves cancel the incoming waves

These redirected waves interfere with the incoming sound waves, reducing their energy before they can reach the ear canal.

This is essentially noise cancelling, but without electronics, microphones, or batteries. It is noise cancellation through physics, not circuitry.

The result is:

• Strong reduction of harmful noise

• Clearer speech

• No distortion

• No isolation

• No electronics to fail

Because ZEM® reduces low‑frequency noise more effectively than plugs or muffs, it reduces speech masking and improves intelligibility — one of SensGard’s most important advantages.