Laprevotte was primarily a violin maker who built his guitars following certain principles of violin design. His maple backs, for example, were carved into an arch and lacked bindings. However, his most radical departure from traditional guitar construction was to abandon fan or ladder bracing in favor of two (sometimes four) longitudinal braces running the length of the soundboard similar to a violin’s bass bar. This arrangement gave rise to a distinctive oval sound hole – a visual trademark of his instruments. 

X-ray of Longitudinal Braces