In reaction to the often poor sound quality at live music events and subsequent issues of noise pollution, Davies Roberts, founder of loudspeaker manufacturer Flare Audio, has developed a new type of speaker which produces a much ‘purer’ sound than those currently used within the live music industries. The following blog post introduces the first of two white papers authored by Roberts and argues that the standards of audio testing should be raised in order to create a better audio experience for artists, audiences, and, ultimately, local residents.
The first paper in the series suggests that the audio industry should test its products to a higher standard and publish the results in its sales material. The paper, welcomed by the Institute of Sound and Communications Engineers (ISCE), argues that a test currently used extensively by audio professionals to measure the sensitivity of loudspeakers does not tell the whole story about loudspeaker sound quality. It claims that a less well-known test, Waveform integrity (Wi), allows artists, audio professionals and the listener to compare the sound reproduction of different products much more effectively.
Loudspeakers should provide ‘as pure a sound as possible’ to enable an unaltered reproduction of the sound created by the musician. The white paper defines a sound as ‘pure’ if it is the exact copy of the original source material and loses none of its detail in the transmission from artist to listener in the process of audio reproduction.
The paper explains how most loudspeaker designs damage sound through resonance and internal reflection within the cabinet. It also describes how manufacturers have traditionally compensated for this, particularly in the last two decades, by the use of digital correction techniques using digital signal processing (DSP).
A Waveform integrity test, on the other hand, measures a sound wave at its point of origin and also as it emerges from the loudspeaker. The more closely the two waves resemble each other, the better the quality of sound reproduction. A Wi test is carried out with a dual channel oscilloscope (ideally, high resolution) and an RTA microphone. By adopting this test, purchasers will be able to initially judge the quality of a loudspeaker simply by comparing Wi measurements in marketing material, prior to hearing a product first hand.
The Waveform integrity test is not intended to replace other testing methods. Instead, it is designed to provide further information to the user in order to better evaluate the sound quality of a loudspeaker. I believe that both the user and the industry will benefit from the application and disclosure of Waveform integrity tests. This white paper puts forward the case for European and International standards boards to raise the standard of disclosure to users by requiring that Waveform integrity test results be included in user information for every loudspeaker sold. Ros Wigmore from the ISCE has backed the proposal, stating that “ISCE welcomes this further understanding of this possible new testing”.
The next white paper will be on Sound Propagation and Dispersion, to be released early 2013, and will also be posted on the Live Music Exchange website. Based on new understanding of sound control, the second paper will highlight that aerodynamics is the fundamental principle behind the directional capability of sound, and how by using an approach of Waveform Integrity all sound can become more directional. It will provide new understanding on how events could thrive in noise sensitive areas, which is crucial if the event industry wishes to continue to see growth.
 One such test is the commonly used technique of a Simple Frequency Response Graph; this is a measure of sound uniformity, however, not of quality.
 Waveform integrity (Wi) is a new term coined by Flare Audio
 Graphs demonstrate how Wi provides a true measure of sonic quality with or without DSP correction
 Audio professionals will be able to initially judge the quality of a loudspeaker simply by comparing Wi measurements in marketing material, prior to hearing a product first hand.