Tailored hearing experiences with Bernafon Alpha
We know that hearing in noise is difficult, even for people with normal hearing abilities. But can you think of the last time that you really had difficulty understanding the person with whom you were speaking? It’s more likely a special circumstance than an everyday occurrence for people with normal hearing. This is because the typical daily listening situations that we encounter are not as loud in terms of signal-to-noise ratio (SNR) as we might think … or are they? Have you ever considered what the SNRs of your daily environments are? It’s information that could be particularly important for your clients.
Life is louder than expected
Widely accepted SNR estimations of typical listening situations fall in a range of positive levels. In 1977, Pearson showed average measurements of speech and noise in various settings. For example, he showed that in primary schools at 1 meter of speaking distance, the SNR was about 1.4 dB, in suburban and urban homes, 1.3 and 1.2 dB respectively, and in department stores 1.1 dB (Pearson, 1977, p. 46). Smeds et al. (2015) reported speech-in-noise situations as having an average SNR of 5 dB. A more recent study measured multiple situations by having participants carry digital recorders for 10 hours a day for 5 to 6 weeks (Wu et al., 2018). This study found that most SNRs fell between 2 and 14 dB, once again, in a positive range.
Based on these estimations one could expect that people with normal hearing should understand the majority of speech-in-noise situations. Although, Moore has written that people with normal hearing generally require an SNR of +6 dB to experience “satisfactory communication” which means that the measured environments mentioned above would still prove challenging (Moore, 2014).
SNR as a fluctuating estimation
But now I will burst the bubble of the positive SNR. A study completed in 2021 took extra steps to achieve more realistic ‘real-life’ SNRs (Mansour et al., 2021). They compared two simulated rooms that were reconstructed to match their actual counterparts of an office and a canteen. They compared the use of a single-channel and two-channel recording system to measure the SNR of the environments and their correspondence with the measurements of the actual environments. The single-channel method consistently overestimated the SNR, meaning that it made it seem more positive than it was. And the results from the two-channel method were not significantly different from the measurements of the actual environments. The real-world estimated average SNRs using the two-channel method were -2.5dB and -0.5 dB for the office and canteen settings (Mansour, et al., 2021, p. 1566). These results appear drastically different than earlier reported SNRs but are in fact consistent with other real-world measures by Culling (2016).
Considering the difficulty with speech-in-noise understanding that people with normal hearing report, and even more so people with a hearing impairment, it’s not surprising that potentially more realistic SNR estimations are poorer than previously thought. Listening environments are diverse and even the same physical locations are dynamic due to varying amounts of people in a setting, the type of noise in that setting, and physical attributes that may change the acoustics and resulting reverberation. Therefore, we can never assume specific levels of SNR, rather accept that they are estimations that will fluctuate.
Hearing aids should adapt to the surroundings and the client
As hearing-impaired listeners require an even better SNR to understand, managing the range of SNRs that one might experience in a typical day requires a hearing aid that quickly identifies and adapts to the changes. Furthermore, hearing-impaired listeners can have completely different hearing experiences despite sharing identical hearing thresholds. Auditory resolution abilities will uniquely dictate the extent to which people can separate the speech from the noise. Likewise, people will have their individual maximum SNRs that they tolerate and that still allow them to effectively communicate in noise.
Tailored listening experiences with Bernafon Alpha
To address speech in noise, Bernafon Alpha hearing aids use Hybrid Noise Management™ that consists of Smart Directionality and Smart Noise Reduction. The directional microphone system and the noise reduction are applied in a manner that is specific to each listening situation to seamlessly manage all types of listening situations. The system constantly analyzes the environment to determine the SNR, the types of noise detected, and the best way to process the signal to keep speech as the primary focus. In addition to these efforts to maximize understanding, are settings that can be adapted to fit individual end user’s preferences. As stated, everyone has a different tolerance for noise, different priorities, and capabilities. Hybrid Noise Management™ gives the HCP the flexibility to create the most appropriate listening experience for each client.
Culling, J. F. (2016). Speech intelligibility in virtual restaurants. Journal of the Acoustical Society of America 140(4), 2418–2426.
Mansour, N., Marschall, M., May, T., Westermann, A., and Dau, T. (2021). A method for realistic, conversational signal-to-noise ratio estimation. Journal of the Acoustical Society of America, 149(3), 1559-1566.
Moore, B.C.J. (2014). Auditory processing of temporal fine structure: Effects of age and hearing loss. World Scientific. Singapore
Pearsons, K. S., Bennett, R. L., and Fidell, S. (1977). Speech Levels in Various Noise Environments (Office of Health and Ecological Effects, Office of Research and Development, US EPA, Washington, DC).
Smeds, K., Wolters, F., and Rung, M. (2015). Estimation of signal-to-noise ratios in realistic sound scenarios. Journal of the American Academy of Audiology 26(2), 183–196.
Wu, Y., Stangl, E., Chipara, O., Hasan, S., Welhaven, A., and Oleson, J. (2018). Characteristics of real-world signal-to-noise ratios and speech listening situations of older adults with mild-to-moderate hearing loss. Ear and Hearing 39(2), 293-304.