chicago fire digital project
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Chicago Fire Digital Project. Commander Leonard Edling Chicago Fire Department. Chicago Fire Department. Portable Radio Audio Intelligibility in Noise Testing June 23 - 25, 2009. Test Overview. - PowerPoint PPT PresentationTRANSCRIPT
MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Chicago Fire Digital Project
Commander Leonard EdlingChicago Fire Department
MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Chicago Fire DepartmentPortable Radio Audio Intelligibility in Noise
TestingJune 23 - 25, 2009
MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Test Overview• Test the radio “Transmitted Speech
Intelligibility” while operating in typical fire ground background noise conditions
• Instructions given to test scorers:– Test messages would be a series of fire ground related radio
transmissions. Most transmissions will have noise in the background.score the perceived speech intelligibility of the received transmission.
– Test were not meant to try and score the “delivered audio quality” of the transmission. Rather, the goal is to measure the transmitted speech intelligibility in various operating environments.
MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Test Overview (cont.)Score: Subjective Scoring Definition:
4
5 100% clear and intelligible speech (100% understood what was being said even though noise was present)
Less than 100% but greater than 50% intelligibility
No Received Message
0% intelligibility (speech is present but not intelligible at all)
Less than 50% but greater than 0% intelligibility
50% intelligibility (I could understand about half of the received message)
0
1
2
3
MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Best Practices• Using the “IAFC Best Practices”, transmit
audio quality and intelligibility can be improved significantly
• Keys for improvement– The position and angle of the radio microphone
• Holding the radio microphone 1-2 inches directly in front of the SCBA Voice Port (IAFC Best Practice, Section 1, Recommendation 2)
– The volume level and clarity of voice • Speaking in a loud (not shouting), clear voice produces
the best transmit audio quality and intelligibility (IAFC Best Practice, Section 1, Recommendation 3)
MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Radio Microphone Positioning
STANDARD POSITION• 3”-5” from Voice Port• Hand blocking port• Facing noise source
“BEST PRACTICES” POSITION • Against Voice Port or near
mouth area• Facing away from noise
source
MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Radio Microphone Positioning
STANDARD POSITION(3”-5” from Voice Port,
Hand blocking port)“BEST PRACTICES” POSITION(against Voice Portor near mouth area)
MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Other lessons Learned• Radios should be optimized for use• Accessories Can have a big impact on performance• Noise Suppression software can have significant
impact• Multiple settings may be needed for different types
of users• PASS Alarm Protocol Identified
– 3 Step Protocol1.Turn off PASS device before radio communications2.Cover PASS device with other hand3.Talk between PASS device chirps
• Training needs to be completed for all radio users
MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
Audio Test Recording Samples
Analog:
Digital:
Analog:
K950 Saw Cutting SCBA Low Air + PASS
Digital:
StandardBest
Practices StandardBest
Practices
Noise Shield
2
CurrentCFD
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MABAS CONFERENCECHIEFS AND COMMANDFebruary 21 – 23, 2011
QUESTIONS?
Commander Leonard Edling
312-745-1045