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What environment is best for the HDL300 system's optimal performance?


The following describes the room environment required for good audio conferencing.

Ambient noise

For the human voice to be clear and understandable, the ambient noise in the room should be at least 20 dB lower than the speech. The noisier the room, the less intelligible the voice; the quieter the background noise, the more comprehensible the conversation. Based on average human speech being in the range of 60 to 65 dB SPL, this would mean that the room should have an ambient noise below 40–45 dBA.


Room reverberation is the measure of how reflective the surfaces are within a room. The more absorbing (less reflective) the surfaces are, the better the microphones will pick up the conversations in the room. Higher reverberation and reflections of speech will cause signal interference and more difficulty in understanding the conversation.

We recommend a reverberation time (RT60) between 0.25s and 0.6s.

Items such as glass, concrete and brick are highly reflective and can cause high reverberation in a room, whereas carpet and ceiling tiles are more absorptive. Using fabric acoustic paneling on highly reflective surfaces will help with room reverberation.

Although the HDL300 system’s Microphone Mist™ technology will work in highly reverberant rooms, optimal performance can be achieved by adding acoustic treatments (e.g., acoustic panels, diffusers) to the room to assist the audio quality.

Last updated: January 31, 2019

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