David Mason R.H.A.D Hearing Aid Audiologist Ampleforth, York.    Tel: 0800 612 7 812
0800 612 7812

David has now retired and has
handed over the business to
Mr Robert Donnan RHAD.

Please be assured that his service and commitment to his clients are in direct parallel with our own. He has recently opened a branch in Fulford, York and has a number of other highly useful resources that you may find useful in the future. This includes Micro suction.

You can have every confidence in his service and I'm delighted to say that he always treats people with consideration and commitment. If you are interested in the latest hearing instruments he will only be too pleased to organise a free trial.

David Mason - August 2016


York Hearing Practice, 92 Main Street, Fulford, YORK YO10 4PS

Freephone 0800 612 7812

High spontaneous acceptance and
excellent customer satisfaction


The Phonak Adaptive Digital prescription formula has been used for many years in Phonak digital hearing instruments. The algorithm aims to decrease the amount of fine-tuning for the hearing care professional to a minimum and offer a pleasant spontaneous hearing experience to the hearing instrument wearer.

In an international study, the fitting data of approximately10.000 CORE platform hearing instrument fittings was collected. An analysis was conducted to determine the amount of fine-tuning that was performed. It was found that the settings preferred by the clients, on average, did not differ by more than 1-2 dB from the precalculated settings. The results of an internal prototype study using the latest generation Phonak hearing instruments, based on the new SPICE platform, also show a high spontaneous acceptance and a high customer satisfaction with the default prescription settings.


The goal of any prescription formula is to support the hearing care professional when fitting a hearing instrument. It suggests the desired amount of amplification and output based on the individual hearing loss, based on findings of scientific research. Next to the widely known and acknowledged prescription formulas like NAL-NL1 or DSL 5a, which are often seen as standards, many hearing instrument manufacturers offer their own prescription formulas, optimized for their hearing instruments. For many years, Phonak has also offered a proprietary prescription formula the Phonak Adaptive Digital formula. In an earlier study that focused on the usefulness of the Phonak Adaptive Digital prescription formula, it could be shown that the use of this algorithm reduced the required amount of fine-tuning and improved customer satisfaction [1]. The Phonak Adaptive Digital prescription formula is constantly evolving to account for technical achievements and latest research findings in the area of hearing science. Enhancements to this formula are intended to continually optimize the benefit for the hearing instrument wearer and offer an optimal first hearing experience. Further reduction of the time needed for fine-tuning for the hearing care professional is an additional important goal. To evaluate the reliability of the Phonak prescription formula in Hearing Instruments based on the CORE platform, fitting data from 10.416 hearing instrument fittings was collected in an international field study. The data was collected with the assistance of numerous clinics and offices in the USA, Germany, Austria, Australia and Belgium. The data was later analysed to determine how much fine-tuning was performed.

Additionally, the reliability of the prescription formula for the latest Phonak SPICE Generation hearing instruments was evaluated in an internal study by fitting 29 subjects with prototypes of Phonak Ambra. Subjective ratings were collected from the test subjects regarding their spontaneous acceptance of loudness and sound quality.

Study setup

The primary data originated from clinics and dispensing offices in the USA, Germany, Austria, Australia and Belgium. The participating hearing care professionals conducted regular hearing instrument fittings, including fine-tuning. They were not informed about the aim of the study beforehand. After initial precalculation, the applied fine-tuning adjustments in the software were automatically tracked and saved. Client information from collected data was removed to make it anonymous and sent to Phonak for evaluation. An overview of the hearing instruments per family that were used in this study is shown in Figure 1.

Fine Tuning

Fig.1: Overview of hearing instrument models

Additionally, 29 test subjects were fitted with prototypes of Phonak Ambra hearing instruments. The test subjects were interviewed directly after precalculated fitting and subjective data was gathered to assess their spontaneous hearing experiences. They were asked to rate according to a five-step scale. Loudness was rated as very loud, loud, just right, soft or very soft. Sound quality was rated as very shrill, shrill, natural, dull or very dull.


The data show that the amount of fine-tuning applied for BTE and ITE instruments did not differ significantly. Therefore, BTE and ITE hearing instruments were combined and grouped according to hearing instrument families. Figure 2 shows the variation between precalculation and applied fine-tuning for the various CORE hearing instrument families, per frequency channel. The curves displayed show the fine-tuning adjustments for soft, medium and loud inputs as well as MPO adjustments.

Fine Tuning

Fig 2: Vertical axis shows the changes from initial fit over frequency

On average, the hearing care professionals in this study adjusted the prescribed hearing instrument settings by max.3-4 dB in single frequency channels. Figure 3 shows the average applied fine-tuning adjustment over the three evaluated input signals per instrument family. The shape of the curves show two effects; a decrease for low and high frequencies most prominent for loud input signals as well as a significant increase in high frequency amplification especially for soft input levels. The latter is most likely caused not by manual adjustments but rather by conducting a feedback test.

With individual data on feedback thresholds the instruments are able to increase high frequency amplification. The reduction of low and high amplification especially for loud input signals is most likely a result of using the experience manager.

The overall applied finetuning, on average, is less than 2 dB,as seen in Figure 3.

The collected data of the internal prototype study show similar positive results. 90% of the test subjects participating in the internal study rated the initial loudness perception after precalculation as comfortable or just right. The remaining three subjects stated the loudness to be „loud“, none of the participants rated the loudness to be „too loud“ or „too soft“.

Four test subjects rated the sound quality after precalculation as dull, one subject rated the sound to be shrill whereas 83% participants experienced the sound quality to be natural and comfortable.

Fine Tuning

Fig 3: Overview of the average finetuning adjustments per HA family


Even though the 10,416 hearing instrument fittings from the international study were conducted by numerous different hearing care professionals using individual strategies, the use of the Phonak Adaptive Digital prescription formula resulted in only minor gain adjustments overall. This implies very good precalculation targets, independent of the hearing instrument family. It ensures a good initial hearing experience for the wearer and leads to a high spontaneous acceptance. The amount of fine-tuning needed is very low, allowing the hearing care professional to concentrate on other important aspects of the first fitting session like counselling.

All the findings of this large-scale study were used to further improve the precalculation of the Phonak Adaptive Digital formula for the latest SPICE platform hearing instruments, Phonak Ambra and Audéo S. The overall excellent results of the internal prototype study imply that the upcoming SPICE platform hearing instruments will continue to provide the hearing care professional with accurate and reliable precalculation targets, and result in a very positive first hearing impression.


[1] Dipl.-Ing. (FH) Martin Lützen, Focus 35 - How Much Fine Tuning Does a Modern Hearing System Require? https://www.phonakpro.com/content/



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