The Importance of In-Mask Communications Harvey David Chambers, Motorola Solutions This is not a technical review of BT technology This is about understanding the fire ground environment and its impact on communications and the available technology and BPs to address communications issues

Agenda Radio Audio Quality Overview IAFC Best Practices SCBA Audio Performance Technology Solutions for Fire Ground

Preface Be Proactive Information is the Key Towards Radio Audio Quality Anticipate Possible Audio Issues Vs. being REACTIVE when audio “issues” arise It’s an Investment Information is the Key

Radio Audio Quality Overview Audio Quality vs. Intelligibility Audio Quality Very, VERY subjective What sounds good to one person is different for another Preference, Hearing loss, Operational needs Intelligibility Main Goal in Extreme Environments Can you understand the radio message? Humans can fill the “blanks”

Radio Audio Quality Overview The Challenge: Creating intelligible radio communications in variable, sometimes high noise and extreme environments while accommodating customer preferences and references

Radio Audio Quality Overview Main Issues Affecting Audio Quality & Intelligibility Background Noise Acoustical Feedback Radio Usage RF Radio Coverage

Background Noise Fire Ground Noise Alarms Smoke, Low Air Alert, PASS Mechanical Pump Panel, Saws, Fans Reduction of transmitted speech intelligibility when operating in a high noise environment SNR Signal to Noise Ratio ≤ 0dB SNR (more Noise than Speech) is BAD for a radio vocoder! Sometimes Difficult and Extreme Situations

↑ Sound Loop Gain, ↑ Feedback Acoustical Feedback is a Natural Phenomenon Occurs when a sound loop exists between an audio input (a microphone) and an audio output (a speaker) ↑ Sound Loop Gain, ↑ Feedback 1. The Sound Loop Exists when a signal received by the transmitting microphone is amplified and passed out of the receiving speaker 2. Further Audio Amplification Sound from the speaker is then received by the transmitting microphone again, amplified further, and passed out through the speaker again… MIC SPKR 3. Acoustical Feedback Results Radio users hear a more pronounced Echo and “Crickets” (Digital) or Howling (Analog) noise from the received audio

Radio Usage Radio Best Practices Accessory & SCBA Design User Voice Speaking in a loud, clear voice Annunciation Radio / Microphone Position Distance from mouth to microphone port Angle between mouth and microphone port Accessory & SCBA Design Technology Intended Use Position (IUT) Microphone Location and Porting

Radio Audio Quality Overview Combination of all these Factors! Main Issues Affecting Audio Quality & Intelligibility Background Noise Acoustical Feedback Radio Usage RF Radio Coverage

Developing and Maintaining Good Habits for Radio Communications IAFC Best Practices In an effort to deliver optimal intelligible audio in the presence of high background noise, the use of “Best Practices” as defined by the International Association of Fire Chiefs (IAFC) along with optimal Customer Programming Software (CPS) audio settings in the radio, have shown to be very beneficial in delivering improved communications. Using the “IAFC Best Practices”, transmit audio quality and intelligibility can be improved significantly. Developing and Maintaining Good Habits for Radio Communications Show of hands for who operates with Scott, MSA, Draeger, Survivair

IAFC Best Practices – Section 1 Use the radio for the initial distress call before manual activation of the PASS in a Mayday situation when practical Ensure that the microphone is placed 1 to 2 inches from the mouth or SCBA voice port with the microphone positioned directly in front of the audio source Speak in a loud, clear, and controlled voice to maximize audio intelligibility Shield the microphone from noise sources to improve the intelligibility of the audio in high noise environments When practical consider using a free hand to muffle a mask-mounted SCBA low air alarm when trying to transmit on a radio Consideration should be given to the location of radios and microphones in relation to PASS devices and other noise generating user equipment

Inverse Square Law In a free field the intensity of sound drops by 6 dB for each doubling of distance from the source.

Noise Level Distance from mouth to device Quiet (office) Noisy (Pump Panel) Loud noise (Fans, Saws) 5” or less Confidential talking Clear normal talking Loud firm talking 8” Loud firm talking Extra loud 12” Extra loud talking Move closer!

SCBA Audio Performance Voice Emitters Mask Characterization Level attenuation Distortion of voice Show of hands for who operates with Scott, MSA, Draeger, Survivair

Voice Emitters Typically where the best audio quality is produced for radio communications Scott MSA Drager

SCBA Mask Characterization

Level Attenuation

Noise Level Distance from mouth to device Quiet (office) Noisy (Pump Panel) Loud noise (Fans, Saws) 5” or less Clear normal talking Loud firm talking Extra loud talking 8” Move closer! 12”

Level Attenuation

Distortion of Voice

Distortion of Voice

Technology Solutions Best Practices Noise Suppression Retractable Microphone Attachment Noise Suppression In-Mask Solutions Bluetooth

Technology Solutions Bluetooth Not all solutions are the same Pros Voice isolation Acoustical feedback Best practices Cons Battery Connecting Audio Features

Summary Audio Quality vs. Intelligibility SCBA Best Practices SCBA Mask Characteristics Bluetooth Pros & Cons