The instrument referred to in "The Beatles: Recording Sessions" is most probably
the "zarb" or "tonbak". They are usually about 17 to 20 inches tall and 12 inches in diameter with a glued on goatskin head. To make a tonbak, a section of a mulberry tree log is taken and turned on a lathe until the desired shape is reached. The inside and outside are then finely finished. It takes a skilled and knowledgeable artisan to make a really good sounding tonbak. The instrument's final appearance will vary from artisan to artisan.