Speech Intelligibility Measurement


SM50 Speech Intelligibility Meter and BTB65 Talkbox

Speech Intelligibility Measurement Kit

The Bedrock Speech Intelligibility Measurement Kit contains everything that you need for speech intelligibility measurements when using the STIPA method, according to most national and international standards. This kit complies with the following standards:

  • IEC-60268-16
  • ISO-7240-19
  • NFPA72 Annex D
  • NEN2575
  • DIN-60849/DIN-VDE-0833-4
  • BS-5839-8


The Bedrock Speech Intelligibility Measurement Kit consists of a Bedrock SM50 Speech Intelligibility Meter and a Bedrock BTB65 Talkbox, calibrated acoustic signal source. Bedrock SM50 is a universal, easy to use speech intelligibility tester, designed primarily for ease-of-use. Additionally, it features a simple, user-friendly touch screen for precise and basic control. The Talkbox is a calibrated acoustic signal source for taking STIPA measurements and more. The Speech Intelligibility Measurement Kit combines both of these devices in a rugged waterproof carrying case.

The functionality of this kit extends far beyond just STIPA measurements, and covers all of the most commonly required acoustic test methods. These acoustic test methods include:

  • STIPA measuring with quick screening mode, or pro mode.
  • Full STI measurements using the direct method in 65 seconds (With firmware 2.0).
  • Speech Level Measurements cf IEC-60268 Annex J. With firmware 2.0.
  • Class 2 / Type 2 sound level meter with fast, slow, A/C.Z-weighting,  and Leq. This conforms to IEC-61672 class 1, and ANSI S1.4 Type 1.
  • Real Time Analyzer – 1/3 and 1/1 octave.
  • FFT analyzer with a detailed frequency analysis up to 32768 lines.
  • RT60 measuring – reverberation times: T20/T30/EDT.
  • Noise Curves – NR, NC, PNC, NCB, RC, RC mark II (With firmware 2.0).
  • Calibrated audio recording.
  • LAeq long-term logging and monitoring.
  • Audio oscilloscope.
  • AC Volt meter for audio line level measurements –  dBU, dBV, V rms (With firmware 2.0)>
  • USB audio device mode – calibrated audio for your PC-based software applications.
  • More functionality will be added through free future firmware upgrades.