Buying Guide・2015-12-15

STIPA Speech Transmission Index Measurement and Electroacoustic/Architectural Acoustic Optimization (Part 1)

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【Written by / Hunk Huang】

In a Public Address system, how do we ensure that the system can clearly transmit voice messages to achieve the goal of "public information broadcasting"? In the past, we used various methods for measurement. For architectural acoustics, we measure the room's Reverberation Time (RT60 for 60dB decay, RT30 for 30dB decay); for electroacoustics, we measure the Frequency Response and Sound Pressure Level (SPL). However, the above values cannot intuitively explain whether the audience actually "understood" the message. The reasons for this include the following: the intensity of the speech relative to the ambient noise, the frequency response of the transmission channel, and the non-linear distortion of the transmission equipment.

The masking of sound reinforcement content by background noise level, and the quality of sound reproduction equipment

Is the speaker energy reaching the audience area direct energy?

Echo (reflection delay > 100ms)

Room Reverberation Time (interaction of sound energy absorption by space) Psychoacoustic effects (masking effect)

The human ear's ability to distinguish words pieced into sentences

Ear fatigue caused by excessive sound pressure levels reduces speech intelligibility

The difference between speech characteristics and noise (e.g., our recognition of native language is higher than non-native language)

Therefore, a measurement technology capable of comprehensively determining whether a public address system can deliver 'public information broadcasting' was identified as a challenge and developed.