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FM Systems with CIs. Purpose of an FM Fitting . Improve speech understanding by optimizing the signal-to-noise ratio (SNR) speaker’s voice is presented at a consistent dB level greater than background noise, regardless of the distance Assist in difficult listening situations Background noise
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Purpose of an FM Fitting • Improve speech understanding by optimizing the signal-to-noise ratio (SNR) • speaker’s voice is presented at a consistent dB level greater than background noise, regardless of the distance • Assist in difficult listening situations • Background noise • Competing conversations • Distant speakers • Rooms with poor acoustics
FM Use in the Classroom: Suggestions for Teachers/Therapists • Precursors to a child’s FM use with their CI: • Approximately 3/6 months of cochlear implant experience • Adequate communicative skills (oral or sign) to provide feedback regarding what they hear • Reliable responses to age-appropriate auditory tasks • Someone trained to perform a daily listening check and troubleshoot the FM equipment • Partnership between teachers, educational audiologists, and cochlear implant audiologists
FM Systems • Transmitter broadcasts FM signal to receiver worn by user • Microphone and transmitter (worn by speaker or placed in middle of a table) • Receiver • Interface cable or headset • Systems tuned to a specific transmitting frequency within a designated bandwidth • Potential problems: • Signals can stray outside of a defined area and privacy cannot be maintained • Other signals can cause interference
Overcoming Common Problems with FM Systems • Interference from outside sources transmitting on the same radio frequency • Use the FCC dedicated transmission band set aside for assistive listening systems! • 216-217 MHz
Connecting to a Personal FM System:Audio-Mixing • Use the sensitivity control of the speech processor to regulate the mix of FM signal and environmental sound • The lower the sensitivity setting, the more dominant the FM signal • sensitivity @ 0 100% FM input 0% environmental • sensitivity @ highest setting50% FM input 50% environmental
Connecting to a Personal FM System:Audio-Mixing • Older processors (MSP and Spectras below SN 34xxx) do not have audio-mixing capabilities and the headset microphone is completely deactivated, regardless of the sensitivity setting • Set the sensitivity to optimal and adjust the FM volume control
Performance Monitoring • Audiologist should perform a functional listening evaluation in the classroom, both with and without the FM system, to measure benefit • Administer an auditory-only task in quiet using the processor alone • Connect the FM system to the speech processor and repeat the task with the transmitter at a distance typical of intended use, ideally in the classroom
Performance Monitoring • Performance should not be poorer when using the FM system • Controls should be adjusted if necessary • Equipment and performance should be monitored regularly
Personal Soundfield Systems • Provide 10-15 dB SNR advantage • No modifications required to equipment • May be less conspicuous and cumbersome • Easy to troubleshoot • Speaker placement is critical • On desk and must be at ear-level of student for optimal effectiveness
Flexibility of Choice on 3G… Wireless
MLCI/MLCI+…. • BW to BTE!
Truly Wireless FM for CI MLx-s MLx
ESPrit 3G MicroLink (MLx) Adaptor • Powered by ESPrit 3G batteries • May reduce battery life by up to 15% • Adaptor + MLx = 3.5 grams
ESPrit 3G MicroLink (MLx) Adaptor Control the mixing HEREnot HERE Microlink Adapter Controls: Monitor earphone socket Mixing function: FM + microphone FM only Microlink FM System Controls: Mixing/volume: Two dot higher level of output One Dot too soft!
ESPrit 3G Accessory Connection • External input • via 6-pin • L-shaped connector “Monitor earphones” will detect headset mic plus accessory input if enabled in software (R126 V2) Inbuilt telecoil enabled via T-switch “Accessory adapter” (Z60121) is required for all accessories and converts 6-pin ESPrit 3G to 3-pin ESPrit connector…or In addition the “Accessory adaptor cable” (Z77081) is required for SPrint accessories using a 3.5mm jack plug
SPrint Accessory Connection Keyed connector for monitor earphones only Monitor earphones will always detect headset plus accessory input External inputvia 3.5mm jack plug for all accessories
Spectra Accessory Connection External inputvia 3.5mm jack plug for all accessories All SPrint accessories with 3.5mm jack plug will directly plug into Spectra 33-series Spectra: No mixing 34-series Spectra: Mixing enabled