2009 Winter Symposium Papers:Sound Quality in Loudspeaker Design and Manufacturing
Our call for papers is now closed. The following have been selected for presentation:
How to cope with production noise during end-of-line testing -
Stefan Irrgang, Wolfgang Klippel, Klippel GmbH Abstract:
Achieving fast, accurate and repeatable QC / EOL measurement in the presence of high level, disturbing ambient noise at the end of a production line is a challenge. Loudspeaker defects have very low energy; 80-100 dB below the fundamental may be still audible. Thus even moderate production noise is in the same magnitude as the defects and has to be detected reliably to avoid wrong pass/fail decisions. The following topics will be discussed:
Detection of critical ambient noise
Repeating and merging tests
Noise cancellation
Using signals immune against noise
Test enclosures and design rules.
Loudspeaker Production Variance - Steve Hutt, Laurie Fincham, THX Ltd.,
Abstract:
Loudspeaker assembly processes and sub-components vary considerably across loudspeaker driver production batches. This should be well understood by loudspeaker designers and users, however ignoring and underestimating these variances and their causes is prevalent. The potential for excessive variation of sensitivity, bandwidth, frequency response and distortion characteristics (etc.) warrants close investigation of expectations, causes of variance and tools and remedies to diagnose and minimize production variance.
Woofer Design using non-linear BL(x) curves - Peter Larsen, Loudsoft Abstract: Drivers can either be designed for target Thiele-Small (TS) parameters or target system response in several ways. And the sound quality depends on excursion, shape of the BL(x) curve, Voice Coil offset, amount of steel, compliance linearity, high power stability and so on. In addition there is a demand for cost savings as the material prices have increased drastically. Practical design examples considering all these aspects will be given.
