Bolt from flybar for W8L three-way line array speaker, made by Martin Audio, c. 2002

Bolt, with nut and 2 washers, from pre-production prototype flybar for W8L three-way line array speaker, made by Martin Audio, c. 2002. Used for fixing the speaker to the flybar.

A line array is a vertical column of closely-spaced loudspeakers that couple acoustically to act as a single sound source that gives more directional coverage, allowing sound to be propagated to a large audience while maintaining an acceptable degree of intelligibility. Although the principle of line array was published by US engineer Harry Olsen in 1957, it was only in 1993 that a practical, large-scale instantiation of the principle emerged, with L’Acoustics V-DOSC, the first commercially produced line array. Since then the line array has become the most common type of sound system used for large events such as arena concerts and outdoor festivals.

W8L was developed by Martin Audio in the early 2000s especially for larger arenas and outdoor festivals. W8L was world's first three-way, all-horn-loaded line array. While early line arrays adjusted directivity by changing the angles between the units, W8L was the first to also use digital signal processing to adjust the frequency distribution between the line array units to further improve intelligibility.

These particular units are part of a set of eight pre-production prototypes that were sent to Martin’s trusted customer, Audiosky, in Estonia, in 2002, for final testing and evaluation before full production began. The design did not change significantly during this process, although the W8L design did evolve in subsequent years until its withdrawal from production in 2014, in favour of more compact units.