The entire hearing aid delay (group delay) relies on three stages: input, digital signal processing (DSP) and output stages. Widex has always designed and optimized every stage of the hearing aid to work efficiently for optimal sound quality.
INPUT: At the input stage, where we have led the market with true input technology, not only did we design A/D converters to deliver the largest linear input range in the industry; we also designed them to be ultra-efficient in terms of time delay.
DSP: We are the only manufacturer basing our signal processing core exclusively on a time-domain filter bank, allowing for extremely low delay and signal processing efficiency from the outset. All other manufacturers have built their filter banks in the frequency domain and consequently must live with the timing and delay constraints of such a design. Widex remains with a time-domain filter bank because it is the best premise for high-fidelity sound and offers the minimum time delay in processing.
OUTPUT: We can deliver an ultra-low delay output stage because of our input sampling rate of 33kHz. 33kHz was chosen as the Widex sampling rate because it maintained the maximum sound quality required by Widex design specifications. At the time, it was considered a design innovation as the Widex chipset was able to deliver this sampling rate with no detrimental effect on power consumption.
It is vital in allowing our low group delay because a high sampling rate contains fewer artefacts, which in turn means less cleaning of the signal at the output stage, allowing for an ultra-low delay output stage.
Our classic sound pathway can amplify and process sound with greater speed than any other manufacturer – this gives a sound quality advantage for all fittings. Plus, with the WIDEX MOMENT™ platform we have made special efforts to further reduce delay in the DSP stage of the hearing aid to address the mild-to-moderate hearing loss categories with the Widex ZeroDelay™ pathway. Therefore, in the WIDEX MOMENT™ platform, sound is processed through one of two available pathways:
The Widex Classic™ pathway on the WIDEX MOMENT™ platform, with heritage DSP features. In effect, all specialized signal processing algorithms are processing stages along the transmission line. A new stage, the Personal Gain Integrator, ensures perfect integration of all these differentials in perfect balance with TruAcoustics™ to ensure the perfection of individualized sound at the eardrum (see above section 2 on TruAcoustics™).
The Widex ZeroDelay™ pathway on the WIDEX MOMENT™ platform, with adapted versions of all relevant heritage features to deliver the best sound with next to no comb-filter effect. As this pathway relies on fast delivery of sound, some features are altered in nature but are still targeting signal-to-noise ratio improvements and instant feedback control. The signal processing features in the Widex ZeroDelay™ pathway mirror the intent of the Widex classic features but adapt them to the faster engine and filter gearing. It is important to stress that operating with virtually no delay does effectively change the opportunity space for feature functionality. Widex PureSound™ is a platform feature for WIDEX MOMENT™, which means it is available in all price points 110-440 and is a true alternative to our Universal program throughout the price-point range. The unique design of the Widex ZeroDelay™ pathway means that Widex PureSound™ includes a series of heritage Widex features (see features in Widex PureSound™ below).
Significant contributors to the performance of hearing aids including Widex PureSound™ are the channels, sound classes and other price point features. The granularity of analysis and processing is determined by channels and sound classes just as in previous families. And as always, the higher the granularity, the higher the specificity of processing.
Widex PureSound™ is available in all WIDEX MOMENT™ RIC products (and future BTE products) and promoted for open and vented fittings with appropriate hearing losses. COMPASS™ GPS will make a recommendation for Widex PureSound™ to be included in fittings for candidates within the fitting range for Widex PureSound™ shown in Figure 4. If the HCP follows this recommendation, the hearing aid will be set up with Universal (P1) and Widex PureSound™ (P2). The HCP can choose to reorder the hearing aid programs and/or set up GPS to do this by default. Widex PureSound™ operates as a substitute for Universal, but there may be situations where the more processed sound via Universal may useful. It is therefore not possible to fit a hearing aid with Widex PureSound™ alone.