Why can’t I hear well in the car?

Sensioneural Hearing Loss
Image 1: Input vs Perceived loudness level. (Source: Refined Audiometris)

Cars and other motorized vehicles pose as a very challenging listening environment. Hearing in a moving vehicle can be difficult especially for those having sensorineural hearing loss with loudness recruitment.

Recruitment is an abnormal growth of loudness. It refers to the perceptual phenomenon of sounds becoming rapidly louder with increasing sound level, leading to the somewhat paradoxical but common request of people with cochlear disorders “to speak louder” followed by the complaint to “stop shouting” (Moore 2003; Bacon and Oxenham 2004)

Based on the above graph, listeners with hearing threshold at 60dB will not be able to perceive any sounds that is presented below 60dB. When a 70dB (moderate) sound is presented, they will perceive it as soft sound (at 50dB). Meanwhile, when 90dB (loud sound) is presented, they will perceive it as loud sound (90dB).

In a car situation, the speaker needs to speak in a ‘balanced’ intensity or loudness level. Too soft will be inaudible while too loud will be uncomfortable to the listener. This will be difficult especially when the listener is surrounded by the engine and cabin noise.

Other than recruitment and hearing loss issue, speech-to-noise signals are also important for speech understanding. Low speech-to-noise ratio (SNR) means the speech sounds softer compared to the surrounding noise. This situation will greatly impact the speech understanding.

Road noise such as the rumbling of the car, the tires on the pavement, outside traffic sounds, plus the heat or A/C system can all add noise and make it hard to distinguish voices. We tend to have our own strategies to deal with all the noise, but sometimes they fail.

So what can you do to hear better in the car?

First off, try to minimize background noise:

  • Keep windows closed
  • Turn the radio down or off
  • Raise your voice when speaking
  • Avoid competing for conversations at the same time
  • Get the attention of the listener
  • If you’re at the rear passenger seat, lean your body forward when talking to the driver.
  • Stop driving and park somewhere safe when you need to talk about something important
  • Speak slowly and use precise and concise words
  • Use an earbud when having a phone-call

If that doesn’t help, then a diagnostic hearing test is recommended.

Difficulty hearing in noise is a common sign of hearing loss and a diagnostic hearing test is needed to determine if that is the real cause for this issue.

If a hearing loss is found, there are many solutions to help, including hearing aids, of course. Hearing aids are designed to improve speech recognition and listening effort in noisy conditions no matter where the talkers are located either behind or beside the listener.

Modern digital hearing aids provide a clearer speech signal and help suppress ambient noise in relation to speech. This makes it easier to hear others in noisy places including in the car.

NuEar’s Circa AI hearing aids even have a special Car Mode that senses when you’re travelling over 10 mph and automatically adjusts your hearing aids to adapt to the sounds of driving. Additional accessories such as your smartphone, Remote Microphone +, Mini Remote Mic, and Table Mic can help amplify speech sounds and reduce the noise. Your companion can speak into it and have their voices stream directly to your NuEar Circa hearing aids.

To get a hearing test, you can visit our local audiologist and hearing care professional in any one of our outlets. You will get a free hearing aid trial and hands-on during your session too.

Reference:

  1. Moore BCJ. An introduction to the psychology of hearing. 5th edn. Amsterdam, Academic, 2003.
  2. http://refined-audiometrics.com/wordpress1/2016/12/09/hyperrecruitment-and-decruitment-hearing/