Audio DSPs take the shocks out of sound

New software is designed to mitigate the problems of acoustic shock in products such as communication headsets.

New software is designed to mitigate the problems of acoustic shock in products such as communication headsets.

Offered on the AMIS BelaSigna 200 and 250 audio processing platforms, the new hardware/software combination will allow manufacturers to design products that protect users from injury, and help employers conform to new workplace safety legislation.

Acoustic shock, a growing problem in workplace environments such as call centres where headsets are extensively used, occurs when a sudden peak in sound reaches a person's ears.

Over the course of the day, the user commonly hears shrieks, whistles, feedback, clicks, pops, or high-pitched fax/modem tones.

Prolonged exposure to these high levels of sound can result in serious long-term harm, including conditions such as tinnitus, vestibular disturbance and hyperacusis (sensitivity to everyday sounds).

Starting on 15th February 2006, employers in the EU - which defines acoustic shock as any sound over 118dB - have a legal duty to reduce the risk of damage to their workers' hearing, under Directive 2003/10/EC.

Other governments and international bodies are also working on the problem: the ITU-T P.360 standard places restrictions on the sound pressure which may be generated by a headset; while organisations in North America and Australia are studying a variety of statutory and voluntary measures.

Unlike passive approaches to combating acoustic shock, a DSP-based approach enables the frequency spectrum of each instance of acoustic shock to be analysed and processed differently, resulting in a tailored response depending on the nature of the sound.

This is critical for properly managing long-term exposure.

With this built-in "intelligence", a much wider range of complex sound scenarios can be managed.

Although any level of signal processing results in a time delay in the transmission of speech, the AMIS solution is unique in its ability to analyse and protect against the acoustic shock with extremely low latency.

"Our new solution combines the programmable BelaSigna signal processing devices with sophisticated algorithms in a configuration that can be easily deployed between the telephony system and the headset electronics", said David Coode, Audio Group Manager at AMI Semiconductor.

"Not only can it be used to mitigate acoustic shock, its powerful DSP capabilities can also be used to perform other audio processing tasks such as noise reduction and audibility enhancement to ensure clear communication".

"In addition, its programmability allows a single hardware solution to be used in diverse geographical territories, which may differ in their precise technical requirements".

The BelaSigna 200 and 250 platforms are complete programmable audio solutions that combine high levels of integration with low power consumption.

They include on-chip analogue-to-digital and digital-to-analogue convertors, filters, amplifiers, and power management, all within miniature packaging.

The devices can be supplied with a variety of audio processing software directly from AMIS and its solution partners; or designers can take advantage of a user-friendly suite of development tools to develop their own unique applications.

Back to top