Defeating Background Noise
BACKGROUND NOISE & HEARING AIDS
Some people often become frustrated with their hearing aids because they can't hear well in restaurants, in automobiles, in movie theaters or auditoriums, and in most other situations in which there is some degree of background noise and/or some distance to the sound source. The result is that these people think they can't be successfully fitted with aids and they "give up". They stop wearing the aid and never return to their audiologist or dispenser. Here's a flash for those people:
1) Hearing aids can enhance the quality of your life significantly in low noise, "living room" situations.
2) No matter what you have been told or heard, hearing aids will NOT function well, if at all, in higher noise situations, especially background speech noise, or at distances more than 8 feet. The actual distance at which you can hear (and understand) with hearing aids will depend upon:
- The amount of background noise
- Distance to the speaker
- The frequency (tone) of the speaker's voice.
People with a hearing loss need a higher speech-to-noise ratio (SNR) than those with normal hearing. The best way to accomplish this is simply to get closer to the source of the sound. You can do this by putting your ear within an inch or so of the speaker, but this may become embarrassing. Or the speaker may be someone sitting across the table from you in a restaurant. Picture yourself dipping your tie or blouse in someone's soup as you lean across the table to hear. The answer, of course, without getting too much sillier, is the assistive listening device (ALD). These devices provide two important functions, vital to understanding speech:
- They get you closer to the sound, usually utilizing a microphone. This reduces background noise and improves the all important speech-to-noise ratio (SNR) dramatically .
- A good ALD amplifier will enhance the high frequencies, keeping the lower speech frequencies at the same level or attenuating them. This is important for the 95% of us with a high-frequency (sensorineural) loss because obviously we need the highs emphasized. But holding down the low frequencies also helps because the lows tend to interfere with our ability to detect high frequencies. This is a physiological phenomenon called "upward spread of masking".
LONG DISTANCE SITUATIONS : 8+ Feet (yes, only 8 feet is considered long distance): If you had a microphone on a 100-foot cord attached to your hearing aid, you could hear under most circumstances by placing the mic near the sound source. For obvious reasons this is impractical. For long distances (note we are defining this as near as 8 feet) we use two approaches, both utilizing sound transmission, usually FM radio wave, or Infrared light wave.
1) The Classroom/Lecture/Tour-Guide Situation: Personal Amplifiers -- this is where you use a personal portable battery-operated wireless FM transmitter with lapel mic that is carried by the person speaking. A receiver with earphone, headset, CI Cord, or neckloop is used by the listener(s). Maximum operating distance may be as much as 1500'. A system such as this consisting of a single transmitter and receiver can be obtained for under $200. http://www.devices4less.com/PersFM.html#anchor_58
2) The Square Dance/ Movie Theater/Church/Auditorium/ Wide Area Situation: Complete assistive device systems for these situations normally cannot be brought to the facility (church, movie) by you, although many people have donated one to their house of worship. The fixed base transmitter (plugged into an electric outlet) must be installed by the facility itself and connected to their sound system (movie projector, PA system, etc.). The assistive device system is owned by the facility. However you may bring your own receiver (Infrared or FM, depending on the type of system installed) or get one from the facility sometimes surrendering your driver's license or your spouse at the main entrance. A transmitter and four receivers for these "wide area" systems, such as churches, etc. can cost as little as $467.99. http://www.devices4less.com/LanguageTranslation.html
SHORT DISTANCE SITUATIONS - The Pocketalker: Up To about 8 Feet: Hearing with background noise at close distances is easily solved by using a personal amplifier like the Williams Sound Pocketalker, $129.99 Read about it here: http://www.devices4less.com/Audable.html It's excellent for listening in restaurants, cars, at card games, and in small groups. Good amplifiers should provide a very good high frequency audio response with about 50 dB of average gain in the higher speech frequencies. Listening may be with earphone, headphones, neckloop, CI Cord, or any device that you can plug into the Pocketalker which has a 3/8"(3.5 mm) jack.