Tyco 579-769 specifications Conclusion

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Conclusion

In Closing

Designing Emergency Voice/Alarm Communications Systems for Speech Intelligibility requires awareness of the area dimensions, anticipated background noise level; wall, ceiling, and floor materials; anticipated occupancy, and any other characteristics that may influence the desired acoustical properties. This guide has presented a summary of those considerations in order to better understand the concept of speech intelligibility.

If an area is quite large, or is expected to have significant reverberation characteristics, or has other complicating influences such as high ambient noise, speaker selection and placement will require sophisticated modeling tools to determine the equipment needed for proper speech intelligibility. However, if the areas of concern are easily defined, are relatively small, and are expected to provide minimal reverberation, the methods described in this guide provide a good reference toward understanding proper speaker selection and placement.

Contact your local SimplexGrinnell representative for additional information concerning the STI-CIS Analyzer and for information about the Simplex line of Emergency Voice/Alarm Communications Systems.

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Contents Fire Alarm Audio Applications Guide Page Copyrights and Trademarks Page Table of Contents Emergency Voice/Alarm Communications Systems Glossary of Terms Related Publications Chapter Speech Intelligibility Overview Speech Intelligibility Importance Designing for Topic See Page # Chapter Background InformationBasic Audio Math Equation 2-3. Power RelationshipsEquation 2-1. The Decibel Equation 2-2. Ohm’s LawEquation 2-6. Adding Decibels Equation 2-5. dB and Sound Pressure LevelsRobinson and Dadson Equal Loudness Curves Sound and HearingSpeech Pattern that Illustrates Modulations Nature of SpeechRoom Acoustics Eyring Equation, used when α Sabine Equation, used when αAreas with high ceilings, specify a more directional speaker Equation 2-8. The Inverse Square Law Speaker BasicsEquation 2-9. On-Axis SPL Calculation SPL = Sensitivity + 20 log87dB 6dB/divisionEquation 2-10. Directivity Factor Q for a Conical Source 51º Critical Polar Angle Calculations 104Listener Height = 1.5 Meters Ceiling Coverage Diameter Equation 2-11. Coverage Area CalculationsSPL Variation by Layout Pattern Layout Pattern Selection Guide2x Edge-to-Edge Minimum OverlapDistributed Wall Mounted Systems Opposite Speaker WidthWall Mounted Speakers In Meters Room Coverage Width Edge-edge Minimum-Overlap Full-Overlap Chapter Speech Intelligibility Frequency of Speech Contribution to Intelligibility Influences on IntelligibilityNo Noise With Added Noise Degradation of CIS vs. Signal-to-Noise RatioBackground Noise Reverberation Distortion Correlation of CIS and with STI and %ALcons Measures of IntelligibilityALcons STI method with faster measurement times STI-CIS Analyzer Talkbox Practical Measurement of IntelligibilityTools for Predicting Intelligibility Page Chapter Emergency Voice/Alarm Communications Systems Advantages Typical Emergency Voice/Alarm Communications SystemParts of an Emergency Voice/Alarm Communications System Class a and B Speaker Circuit Wiring Chapter Regulatory Issues From Nfpa 72, 2002 Edition AudibilityHigh Background Noise Large Areas Intelligibility Intelligibility Certification Page Chapter Speaker System Design Method Determine the speaker-to-listener distance D2 Speaker Design MethodRecommendations for Maximizing System Intelligibility ITool Office Space Example Applying the MethodsOffice Space Speaker Location Guide Corridor Design Example Corridor SPL Distribution Corridor Speaker Location GuideITool Gymnasium Example 10. Gymnasium Speaker Location Guide 13. Lobby Example 15. Lobby Layout Applying the Methods Conclusion Page Chapter Glossary of Terms Glossary Glossary Page Index IN-2 Page 579-769 Rev. C