Hearing aid manufacturer updates its acoustic measurement systems
21 June 2006
Widex, a pioneer in the hearing aid industry and one of the world’s leading producers of high-quality hearing instruments, is a Danish company established in 1956 by Christian Tøpholm and Erik Westermann. Still family-owned, the company’s hearing instruments are marketed and distributed through an international network of distributors in 80 countries. Some 97 percent of Widex’s production is exported.
The relationship between Widex and Bruel & Kjaer started 39 years ago, so Widex’s search for a new measurement platform to replace the legendary Type 2012 naturally included Bruel & Kjaer. The new instrumentation would not only have to accommodate Widex’s current needs but also represent a secure investment for the future.
The challenges of hearing aid design
The ultimate goal for hearing aid designers at Widex is to give users the same opportunities for communication as people with normal hearing. Hearing aid designers take into consideration a long list of expectations, and corresponding challenges such as improving speech intelligibility in noise, reproducing Nature’s sounds, ensuring that soft sounds are audible and loud sounds are never uncomfortably loud, effecting optimum music reproduction, and improving the user’s perception of his or her own voice.
Although no hearing aid can restore normal hearing, recent advances in digital electronics, acoustics and audiological science have combined to make today’s instruments of greater help than ever before. Widex believe it has the products and technology to help the hard of hearing to get the most out of everyday situations.
Keeping it in-house
Widex is a self-sufficient company, doing all of its research and development, testing, design and production in-house. This knowledge-based company is at the cutting edge of innovation within hearing aid technology, earmarking considerable resources for audiological and technological research to yield state-of-the-art, reliable hearing instruments. Like Brüel & Kjaer, Widex has been in the business of innovation from the beginning. For example, it developed QUATTRO, the first hearing system making use of remote control, and Senso, the first fully digital in-the-ear hearing aid, up to the award-winning Senso CIC (completely-in-canal) model.
When a company of Widex’s calibre decides that its current acoustic measurement platform can no longer fulfil its technical requirements, huge effort is put into an intense investigation of all possible solutions on the market. Only the best is good enough.
Open and flexible solution required
Widex’s main requirement was a solution able to make the traditional standardised electroacoustic measurements performed on hearing aids. For many years, Widex has successfully made these measurements using the Type 2012 with its own dedicated software. However, a technology-driven company such as Widex also required a solution that was open and flexible enough to perform measurements not previously possible with the Type 2012. And measurements such as noise floor, directivity, EMC immunity, etcetera, were also considered to be important.
Introducing the PULSE platform
Brüel & Kjær presented a solution fulfilling the essential requirements, and introduced the PULSE platform to technicians, engineers and management at Widex. It is easy to imagine how attractive the PULSE platform must have appeared to a customer familiar with the user interface of the Type 2012. However, Widex’s Measuring Engineer R&D, Søren Christensen, responsible for finding the replacement, was initially cautious.
Shortly after the introductory meeting, Widex engineers attended two days of PULSE training at Bruel & Kjaer University in Denmark, with Bruel & Kjaer engineers on hand to provide all the support needed. The primary objective of this training was to ascertain to what extent a standard PULSE system could replace the Type 2012. PULSE SSR Analysis Software Type 7772 went a long way to satisfying the requirements, leaving only two tasks outstanding which could easily be resolved with the help of VBA (Visual BasicH for Applications) programming.
Out with the old, in with the new
Widex is the first customer to use PULSE 9.0, and in the months after delivery Bruel & Kjaer following its progress closely, helping it to successfully make the transfer to PULSE.
The measurement system supplied to Widex includes the PULSE Electroacoustic Test System, PULSE Data Recorder, PULSE Time File Management, and PULSE Data Manager, 5-user. This set-up allows Widex to make a comprehensive range of measurements on hearing aids.
Gain and output measurements include output sound pressure level response, full-on acoustic gain, frequency response, the effect on gain with different battery impedance or voltage settings, and OSPL90 with different battery impedance or voltage settings. Measurements of amplitude non-linearities include harmonic distortion with different battery impedance or voltage settings, and intermodulation distortion with different battery impedance or voltage settings. Measurements of internal noise generated are determined by 1/3-octave analysis. Induction pick-up coil measurements include frequency response and harmonic distortion.
Automatic gain control measurements include input/output characteristics for sinusoidal signals and dynamic output characteristics for speech signals at different levels.
Special Test Mode measurements include the effect of band gain control on the basic frequency control, group delay, and phase and amplitude characteristics. Real Mode measurements include input/output characteristics at different bands and filter settings, attack and release time, oscillator frequency sensitivity and range, and absolute gain level check microphone noise squelch at different bands.
The future for Widex looks bright indeed. With untiring commitment to R&D, and now with the help of the PULSE platform, Søren Christensen and his colleagues can only succeed in their quest to break new ground and enhance hearing aid performance.
Contact Details and Archive...