This Month’s Topic for the New Fitter Is… New Fitter News
Directional Microphones Directional Microphones are a proven solution for increasing intell...
This Month’s Topic for the New Fitter Is… New Fitter News
Directional Microphones Directional Microphones are a proven solution for increasing intelligibility and communication in noisy environments with a well fitted hearing instrument.
Monitored Directionality
Adaptive Directionality with Speech Spotter
Adaptive Directionality
Fixed Directionality
1970s
1990s
Mid-2000s
2008 Volume 1, number 7
Directional Microphones, cont.. The interfering effect of background noise is the single greatest problem reported by hearing aid wearers. Directional microphones are the only proven form of signal processing that can improve the signal-to-noise ratio in a way that leads to improved intelligibility. They are available on most hearing instruments: both behind-the-ear and custom styles. The only reason for not choosing a directional microphone is when a patient will only wear a completely in the canal (Invisa) or mini canal style hearing aid (Petite).
New Fitter News – Pg 2
Volume 1, number 7
Directional Microphones, cont.. Fixed Directionality- The earliest type of directional systems; this includes both one microphone with two port openings and the use of two separate one port microphones. Fixed directional microphones do not vary from moment to moment. Although they require a manual switching to the directional setting they do reveal improved intelligibility in a noisy setting. Fixed directional microphones work best when the signal of interest is in front of the listener. Due to low frequency equalization, fixed directional microphones can be perceived to be a little noisier than omni directional microphones.
a. Omni directional microphone b. Two port opening for one directional microphone c. Two separate one port microphones
New Fitter News – Pg 3
Volume 1, number 7
Directional Microphones, cont.. Adaptive Directionality- Unlike fixed directional microphones, an adaptive array varies depending on where an unwanted noise is coming from. The adaptive directional microphone is more effective in canceling out unwanted sounds to the sides of the wearer than the fixed directional microphone. While it still requires manual switching to the directional function, it is more effective in noise. Performs ideally when one noise source is present. Reverberation of sound can decrease the effectiveness of the adaptive array.
Adaptive Directionality with Speech Spotter- Hearing aid automatically switches to directional microphones depending on the analysis of the acoustic environment. Because 30% of users do not change to the directional mode in noisy situations, using Speech Spotter will solve this dilemma. Almost like having two memories in one; one omni directional and the other adaptive directional. Patient does not have to make the decision on which memory to choose.
New Fitter News – Pg 4
Volume 1, number 7
Directional Microphones, cont.. Monitored Directionality- focuses on the functioning of the entire auditory system. Monitored Directionality is the first binaural strategy taking advantage of the natural noisereduction capabilities of an integrated auditory system Many users would like to be aware of the surrounding sound environment and not be cut-off Users require good speech understanding in noise The choice of sound source can change over time Monitoring and focusing at the same time requires an ”asymmetrical” fitting Monitor Ear = Omnidirectional Focus Ear = Directional The monitor ear, fit with the omni-directional microphone, allows the user to still have the peripheral awareness eliminating “tunnel” sensation. The user is still able to attend to signals outside of the standard directional beam width. The focus ear provides maximum directional processing that is instantly available. The overall effect of combining the two allows for the benefits of both, while eliminating all of the secondary problems associated with traditional directional systems. The whole auditory field is available and accessible allowing the user to attend to or disregard signals at their choosing. New Fitter News – Pg 5
Volume 1, number 7
Directional Microphones, cont..
Beltone Circuits
Directional Microphones available
Reach
Monitored Directionality, Adaptive Directionality with Speech Spotter, Adaptive Directionality and Fixed
One/Marq 17
Adaptive Directionality with Speech Spotter, Adaptive Directionality and Fixed
