Banjo Head types
Posted: Tue Jan 24, 2012 1:18 pm
In my mind there are two basic types of banjo heads: Tensioned and non-tensioned. Non-tensioned banjos include such things as wood-topped banjos, cookie tin banjos, gas can banjos, etc. They lack the "true" banjo sound because that sound depends on a thin, tight membrane as the sound producer. That brings us to tensioned heads. I can think of three general categories for tensioned heads: Self-tensioned, adjustable tensioned, and permanently tensioned. Self tensioned heads would be featured in such banjos as tackheads and mountain banjos where a natural skin head is installed wet and allowed to shrink tight as it dries, and in other designs using materials that can be shrunk using heat or other methods. I am not aware of another method besides heat to shrink head material, but I would be very interested to find one.
Adjustable tensioned heads are the modern norm in the banjo world. They can be categorized according to the location of the adjustment mechanism - external to the rim, or internal to the rim. Almost all commercial banjos have external adjustment mechanisms - brackets, hooks, nuts, and a tension ring. A few substitute bolts for the hooks and nuts - these are commonly tensioned from the top of the hoop (top tensioned) and have special tensioning rings. Internal adjustment mechanisms are much more rare, and seem to be the province of amateur or small-time builders, who rely on standard hardware rather than specialized banjo hardware, for their tensioning parts. Usually these function by pushing a tension/tone ring up against the banjo head, via some type of screw jack.
Permanently tensioned head designs are in many respects closer to self-tensioned head designs, but with the important difference that the head material is non-elastic and non-shrinking. Instead, during construction of the banjo pot, the material is stretched (if one can "stretch" a non-elastic membrane) tightly over the tone ring or rim, and then fastened permanently into place. This can be accomplished by using a commercially made hand-drum for a pot, or by using some temporary tensioning jig to apply tension while installing the head on the rim.
Here are some pictures of pot designs I have built using the above methods.
Adjustable tensioned heads are the modern norm in the banjo world. They can be categorized according to the location of the adjustment mechanism - external to the rim, or internal to the rim. Almost all commercial banjos have external adjustment mechanisms - brackets, hooks, nuts, and a tension ring. A few substitute bolts for the hooks and nuts - these are commonly tensioned from the top of the hoop (top tensioned) and have special tensioning rings. Internal adjustment mechanisms are much more rare, and seem to be the province of amateur or small-time builders, who rely on standard hardware rather than specialized banjo hardware, for their tensioning parts. Usually these function by pushing a tension/tone ring up against the banjo head, via some type of screw jack.
Permanently tensioned head designs are in many respects closer to self-tensioned head designs, but with the important difference that the head material is non-elastic and non-shrinking. Instead, during construction of the banjo pot, the material is stretched (if one can "stretch" a non-elastic membrane) tightly over the tone ring or rim, and then fastened permanently into place. This can be accomplished by using a commercially made hand-drum for a pot, or by using some temporary tensioning jig to apply tension while installing the head on the rim.
Here are some pictures of pot designs I have built using the above methods.
