Audio analysis for quality control

A UK manufacturer has integrated Prism Sound's Dscope Series III audio analysis platform into a software system that controls the manufacturing process.

Sonifex is a manufacturer of broadcast audio equipment for the radio, TV, security and telecommunications industries.

Sonifex launched a project in the late 1990s to develop its own in-house software system that would form the backbone of the organisation.

This software package was designed to integrate all areas of its operations into a single system, including development, logistics, purchasing, manufacturing, end-of-line test, and shipping, CRM and servicing.

Chris Stills, technical director of Sonifex, said: 'In the late 1990s, we realised that we needed to modify the way we controlled our manufacturing process so that we could incorporate stock control, invoicing and accounts.

'We bought an Exel system called EFACS, which allowed us to do a lot of what was needed in terms of stock control and production planning.

However, the system was very cumbersome and wasn't really suited to the needs of a smaller company where one person usually has more than one task to perform.

'EFACS required the user to open different screens for different applications and therefore it was very clunky if you were trying to multitask.

Sonifex had its own in-house software expert take a look at the system to see how it could be improved.

A new front end was created - ProTest.

This subsequently evolved further, enabling Sonifex to integrate its contacts database for email, its stock control and its works order process.

Stills added: 'Eventually, all we were missing was a way of integrating quality control [QC] tests.

'QC testing relied on the tester manually entering a serial number into ProTest to confirm a unit had been tested, and there was no way of linking that serial number with the unit's test result data.

'We ended up with lots of bits of paper being printed out and photocopied, but not kept in the system.

Every Sonifex product is tested at various stages during the manufacturing process, with these tests covering individual modules and final testing once the finished product is ready to be shipped to the customer.

Sonifex eventually chose Prism Sound's Dscope Series III audio analysis platform, the main deciding factor was that the system could be easily integrated into its ProTest system, enabling the company to develop its own user interface.

Dscope Series III is a measurement system for analogue and digital audio generation and analysis, including digital audio carrier analysis, acoustic transducer testing and testing of Windows sound devices.

This industrial strength audio test and measurement system comprises a Windows PC software application (XP and Vista compatible) coupled with an external high-precision audio I/O processor for equipment-under-test (EUT) connections.

In Sonifex's case, Dscope is automated using ActiveX control from the ProTest software suite.

The net result is very rapid diagnosis and correction of any manufacturing faults, with detailed test records being written directly into the ProTest system, giving a complete record associated with every serial number of every product ever built.

This has, in turn, led to far more effective component batch control of products on the manufacturing lines, and more efficient technical support of products in the field.

A complete test and service record for any individual product can be instantly recalled, and this can be cross-referenced to individual part numbers or batches of raw materials and components.

Stills said: 'The best thing about the new system is that it is very easy to use and gives us full traceability on any component in any of our products.

'PCB bar codes are matched to product serial numbers, so if there is a problem we can not only find it quickly but also see who assembled each part and who inspected it.

'If recurring problems occur, we can address them by designing out weaknesses, improving operator training and by checking products against known fault lists from the previous six months.

Sonifex has thus been able to standardise on the Dscope Series III platform for both development and QC testing purposes, allowing engineers to share results and test procedures between departments.

According to Chris Stills, Sonifex's technical director, there are now 10 Dscope Series III units at the company's facility - four in the research and development department, and six on the production lines.

Simon Woollard, applications engineer at Prism Sound, said: 'Sonifex was originally testing products manually with equipment that could not be automated, and needed a test solution that could be integrated within their own system.

'Dscope was able to provide the features the company was looking for, thus helping to reduce test time and reduce manufacturing costs accordingly.

Chris Stills said: 'Before we implemented our new software and automated test procedures, we were testing each unit individually, which took forever.

'Now we have designed and manufactured our own automated switcher unit that can take up to 24 balanced audio feeds at any one time and present them to any of the Dscope Series III inputs or outputs.

'We have sections of 25-way D connectors with a breakout cable to whatever product we are testing.

'Because many of our products have the same connectivity, it is possible for us to use these cables across a variety of different products under test.

'Occasionally a product will have a bespoke connector, but in that situation we simply make up a new lead.

'For the testers, the procedure is very simple - all they have to do is match up the right colour lead, plug it in and press go.

'Now, if someone needs a specific test result, they can simply call it up as a PDF.

'The whole thing is done automatically,' he added.

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