Hardware: The FocusLite has a passive attenuation rating but the internal noise level does not always reflect that. Why?

The SNR value is calculated from an average of the passive attenuation across a range of noise frequencies. However, the headset (and all ear defenders) will actually have different attenuation at different frequencies ranging from around 10dB at very low frequencies to 35dB at very high frequencies.

As well as this, the FocusLite also has level-dependant functionality so it will play back the external noise at the same level as the external noise (or quieter depending on the selected volume level) up to 82dB(A).

Please see here for more information on the level-dependant impact from the internal speakers.