Irish bouzouki when having a longer scale length. The fifth course is usually either a lowest bass course tuned to C2 or D2 on an instrument with a long scale, or a highest treble course tuned to G4 or A4 on a shorter scale. Luthier Stefan Sobell, who coined the term "cittern" for his modern, mandolin-based instruments, originally used the term for short scale instruments irrespective of the number of their strings, but he now applies "cittern" to all 5 course instruments irrespective of scale length, and "octave mandolin" to all 4 course instruments, leaving out bouzouki entirely. Mandolin-family luthiers producing an
Strings (tennis) common changes. Some manufacturers, such as Gosen, label nylon strings with words like "sheep", as in sheep intestine, although such strings contain no gut. Synthetic gut, as it is used for mono-filament nylon strings, is now a misnomer, as the creation of multi-filament strings has provided players with a better approximation of natural gut's performance. Modern "synthetic gut" is actually a multi-filament string that holds its tension extremely well and which has a dynamic stiffness profile that is closest to natural gut, although the industry continues to apply the term to mono-filament nylon strings. Multi-filament strings, known commonly as "multis"