Advanced three-stage process

This section describes Sordin’s passive models, which are based on mechanical attenuation using three layers of noise-reducing materials. Our electronic hearing protectors are based on the same principle, but are also complemented by digital noise compression technology to ensure a maximum noise level of 82 dB(A).

Different layers reduce different frequencies

Noise is reduced in an advanced three-stage process, gradually bringing down the noise level. As the sound wave passes through the hearing protector, different frequencies are attenuated more effectively by different layers – combining to give the product its total attenuation level, or SNR value.

The three components are called the outer, the middle and the inner layer. Let’s follow an imaginary sound wave propagating through the hearing protector from the outside and in, beginning with the outer layer, or the cups.

Stage #1: The outer layer

The cups are made of ABS polymer and reduce mainly low-frequency noise. The thickness of the absorbing material is the main factor determining the hearing protector’s overall attenuation. The cups efficiently reduce noise entering not only through the ear canals, but through the skull bone around the ears as well – making over-the-ear protection generally more effective than ear plugs.

Stage #2: The middle layer

The middle layer consists of the insert, which is made of polyurethane, or foam. The insert reduces noise of higher frequencies, from 1,000 Hz and above. It also contributes to make the sound image as comfortable as possible for the user.

Stage #3: The inner layer

Finally, right next to the ear, we find inner layer – the sealing rings. Just like the cups, the sealing rings reduce mainly low frequency noise. It is of crucial importance for the product’s overall attenuation capacity that the rings seal tightly around the ear. Sordin’s sealing rings are replaceable and spare foam or gel rings are available as part of Sordin’s hygiene kits