When I was 12 I noticed electronics. By 13 I was printing circuit boards and assembling all sorts of gadgets such as flash dance, sound and motion detectors, moisture and water level sensors, walky-talky and of course amplifiers, analogue and digital ones. Later on, in university, I studied different subjects, but amplifiers stayed as my favourite subject.
Fast forward 30 years, as I write this post, there is a pair of high-fidelity, super discrete digital amplifiers in my ears! As an electronics enthusiast, and an audiologist with impaired hearing I use the benefit of the doubt in the products that I recommend to my patients, so I always try them for a while to see how they sound.
Digital is the way forward
The direction of hearing aid technologies has been digital for the past 2 to 3 decades. Digital technology brings tons of benefits to designers and product developers. It has enabled hearing aid manufacturers to build algorithms for noise reduction, wind sound control, connectivity and streaming and many other cool features in the advanced hearing aids that have come to the market in the past decade. The latest of all is artificial intelligence (AI), machine learning algorithms and of course telecare which just become a hot feature during the pandemic.
The benefits at a cost
The benefits that digital technology brought to the world of hearing aids were not for free. The sound arrived at the sensitive microphone of the hearing aids is converted to digital, then a lot of processing is done on the signal to bring in those cool features to the wearer, and at the end, the signal needs to be converted from digital to analogue so the wearer can hear the processed sound, hopefully, louder and clearer. The conversion of the signal (twice) and the processing of it in the hearing aids takes time. If the delay (call it latency) is more than 5 milliseconds the wearer would notice the distortion as the amplified sound would interfere with the direct sound received at the eardrum through the vent in open fittings. The combined sound would feel like hollow, with a noticeable difference in sound timbre. The higher the number of channels of the hearing aid and the deeper the processing (e.g. noise reduction) the longer the delay.
The problem is much less of a concern in closed fittings when the hearing loss is large and the wearer needs to receive most of the spectrum of the sound through amplification anyway. However with the majority of the hearing aids being fitted open for patients with mild to moderate hearing loss the latency due to delay in signal processing in digital hearing aids is a major concern in the quality of the sound, hence acceptance and engagement of the patients, well actually until the arrival of Widex Moment.
What is the sound processing difference in Widex hearing aids?
Widex aims to respect all sounds by preserving all details, respecting auditory system functions, and applying extreme sound processing only when necessary.
Widex is the only major manufacturer to make use of a Time-domain filter bank for sound filtering. A Time-domain filter bank has narrower bands in the low frequencies and broader bands in the high frequencies, mimicking the way the cochlea would naturally filter and analyse sound, where low frequencies are more sensitive, requiring more detailed analysis, and high frequencies are less sensitive, requiring less detail.
The full frequency range can therefore be covered with fewer frequency bands, meaning less processing time, no hearing aid delay, distortion or artefacts. The SmartRICs are built upon Widex’s Zero delay technology, Puresound; Setting new industry standards for natural hearing. A huge factor in Widex’s zero delay technology is the use of a Time domain filter bank.
Who wins the race in processing the signal?
In 2020 a group of researchers compared several premium hearing aids in terms of their latency time (full article here). As demonstrated in Figure 1 PureSound technology by Widex provides an average of 0.5 milliseconds, much less of the delay in other advanced hearing aids.
Figure 1
As expected, the latest product by Widex (buy Widex Moment) showed (figure 2) superior showed a smoother and less distorted output signal.
Figure 2
The results of the field test of the PureSound technology did not surprise anyone. As expected majority of the subjects with and without hearing loss chose Widex when tested for the sound quality of the hearing aid when tested anonymously (see Figure 3).
Figure 3
I have a pair of Widex hearing aids, how do I insure my hearing aids?
Please see this link for more guidance on hearing aid insurance.
Conclusion
I am extremely pleased with how my trial Widex Moment hearing aids sound. I am an experienced hearing aid user and you would say that my brain is used to the processed signals. However, in reality, when I do wear a pair of new hearing aids to test them still it takes a couple of days for me to start forgetting about them (not remembering that I am wearing them).
With Widex Moment, I forgot that they are in my ears in a matter of a couple of hours.
Please feel free to share your experience about the latency and distortion of sound in your hearing aids, or your experience with Widex Moment at the bottom of this article.
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