Modal parameter variability in industrial electric guitar making: Manufacturing process, wood variability, and lutherie decisions

• Quality assessment at the end of a production chain.
• Quantification of modal parameter variability of electric guitars in an industrial context.
• Comparison between variability due to lutherie decisions and due to the making process.

Recent studies showed that mechanical coupling between structure and strings can alter the sound of the solid body electric guitar. Modal frequencies and damping ratios of the structure can explain some sound differences between instruments. These vibratory parameters can vary because of lutherie decisions (e.g. intentionally fitting guitars with different woods for sound quality purposes), wood intrinsic variability, or making process variability. Yet the vast majority of solid body electric guitars comes from an industrial mass-production: the manufacturing process is designed for producing guitars that are the most similar possible. However, musicians and makers know that guitars of the same model both share features, and still have some individual properties. The experimental quantification of the modal parameter variability of nominally identical electric guitars in an industrial context is the aim of this article. This variability is assessed on one guitar set, and compared to other industrial objects. A second guitar set is investigated: it consists of guitars with maple or rosewood fingerboard, all other specifications being identical. This second set allows the comparison between making process and wood variability, with the variability due to an intentional lutherie decision: the change of the fingerboard wood.