Gallo Acoustics

Gallo Acoustics don’t make boxy speakers, there’s a better way in eliminating resonance and internal diffraction, the two main causes of loudspeaker distortion.

Speech Intelligibility STI

Speech intelligibility is measured by reproducing a known signal (the STIPA test signal) and measuring the quality of that signal as it reaches each of the measurement positions. The IEC 60268-16 standard for STI defines how any degradation in the signal is measured and the intelligibility result displayed as a single number from 0 (unintelligible) to 1 (excellent intelligibility). Measurement units are STI (Speech Transmission Index) or CIS (Common Intelligibility Scale).

Factors that influence the intelligibility of speech

  • sound pressure level (speech must be loud enough, but not too loud)

  • ambient noise level (e.g. crowds or passing traffic)

  • reverberation time RT60 (sound reflects off smooth surfaces; we need some reflections but not too many)


Also, if a Public Address (PA) system is being used for the announcements


  • frequency response of the PA system (e.g. too much bass)

  • signal-to-noise ratio (i.e. quality of the system)