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Enhancing Communications For the Hearing Impaired

FM. Enhancing Communications For the Hearing Impaired. Courtesy of AVR Communications Ltd.

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Enhancing Communications For the Hearing Impaired

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  1. FM Enhancing Communications For the Hearing Impaired Courtesy of AVR Communications Ltd.

  2. Everyone has trouble hearing in noise, from a distance, and in reverberant environments.For those with hearing aids, this troublesome trio; Noise - Reverberation - Distancecan make understanding speech, fatiguing at best - and impossible at worst.

  3. Difficult listening situations in which the speaker-to listener distance is about 2.5 feet: • Conversation at a large party • Conversation between a clerk and a customer in a crowded store. • Difficult listening situations in which the speaker-to-listener distance is about 5 feet. • Talking to a waiter at a busy restaurant. • Social gatherings of 5 to 10 people. • Difficult listening situations in which the speaker-to-listener distance is about 10 feet: • Talking to your spouse across the room • A board meeting • Watching TV • Difficult listening situations in which the speaker-to-listener distance is 20 feet. • Taking a class • A lecture or stage performance • Talking with someone across a large room

  4. a 100 90 • Normal Hearing 80 70 PERCENT CORRECT 60 • Hearing Impaired 50 40 30 20 10 0 -6 0 6 12 18 24 SPEECH/NOISE RA TIO Speech discrimination scores as a function of S/N ratio Adapted from Dirks, Morgan, and Dubno 1982 a

  5. The effect of noise and reverberation on speech perception capabilities of hearing impaired people is severe, more so in combination than separately. Hearing Aids only make things worse in a noisy and reverberant environment.

  6. Normal Hearing (Quiet) Unaided Hard of Hearing (Quiet) Aided Hard of Hearing (Quiet) Normal Hearing (S/N=0dB) Unaided Hard of Hearing (S/N=0dB) Aided Hard of Hearing (S/N=0dB) The effect of reverberation and noise Speech Intelligibility Scores Under Different Reverberation Times and S/N Ratios: 100 90 80 70 60 Speech Intelligibility Scores % 50 40 30 20 10 0 0.0 0.4 1.2 Reverberation Time (Sec.)

  7. The effect of Distance on the Speech to Noise Ratio

  8. S/N =+24 S/N =+18 S/N =+12 S/N =+6 S/N =0 S/N =-6 S/N =-12 Speech-to-Noise ratio as a function of distance in a room with an ambient noise of 60 dB SPL 84 78 72 66 60 AMBIENT NOISE SPEECH LEVEL IN dB SPL 54 48 0 4.5" 9" 1.5' 3' 6' 12' 24' MICROPHONE/CHILD DISTANCE FROM TALKER a

  9. The FM Advantage • A well known solution is to use FM technology. • Speech is directed through an FM wireless microphone to a remote FM receiver and the speech sounds as loud and clear as if it originated only inches from the ear.

  10. VC S X10 X100 3’ from Microphone Output120dBSPL115dBSPL Input +Speech:60dBSPLNoise: 55dBSPL Conventional Hearing Aid Hearing aids amplify noise, reverberation and speech the same way. Hearing aids do not change the signal to noise ratio . Gain =60dB 60dB Speech to Noise Ratio +5dB

  11. FM System ANT VC FM Receiver S X100 ANT FM Transmitter 4” from Microphone Output120dBSPL100dBSPL Input +Speech:80dBSPLNoise: 60dBSPL By placing the microphone close to the speaker, an FM system improves the signal to noise ratio . Gain =40dB 40dB Speech to Noise Ratio +20dB

  12. BTE FM Receiver/Hearing Aid FM Microphone Transmitter FM - The Wireless Link

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