Dorset Sound & Communications

Sound system design for the 21st Century

Sound Tips
Intelligibility

Intelligibility is the ability to hear and understand words. It is a term that has become of supreme importance in the world of sound and acoustics. Intelligibility has only been really understood in the last twenty-five years with the increasing capabilities in instruments to measure and observe acoustic conditions.

Intelligibility is really the ability to distinguish the consonants of speech (B, C, T, D, etc.) which allow us to understand individual syllables for example the difference between "bat", "bad", and "pad". The consonants all lie in the midrange frequencies between 1000 and 4000 Hertz. Intelligibility is hindered by echoes, background noise, bass boominess and frequency dependent cancellations. Cancellations are caused by mic and speaker positions. It is one of our most important design criteria.

There are four acoustic conditions that affect intelligibility.

Echoes in the room that are caused by flat parallel walls bouncing sound energy back and forth.

Reverberation (not the same as echo) or how long sound hangs around bouncing randomly off of the irregular surfaces of the room.

Ambient noise or the background noise from air handlers, traffic, audience noise and machinery.

Speaker placement is important to control echoes, prevent "dead spots" and get the highest level of direct sound to listeners.

Give DS&C a call for help designing, building your sound system and the training to use your sound system effectively. We can also set up preventive measures and scheduled maintenance visits. Don't be caught unprepared. Enjoy effortless sound. Do it now!          

 

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