The following is some information and observations about clavichord listing cloth,  its functions, applications, useful working characteristics, and the interdependency of these elements.
 

FUNCTIONS

I believe the primary function of the cloth is to dampen the vibrations of the pre-lengths and to dampen the sounding length when the tangent is dropped from contact with the string.

A secondary function, or one at least which the cloth is sometimes required to fulfill, is to increase the resistance of the strings to the tangent’s push by tightly weaving neighboring pairs together.  If woven too tightly the impact of a tangent hitting a string pair will be transmitted through the entire string band, united by the tight listing, to the bridge and emerge through the soundboard as a thump or whunk kind of noise usually pitched at the lowest cavity/soundboard resonance pitch.  For this reason it is better if other elements are used to determine the touch resistance of a clavichord (string gauges, pre-lengths, key leverage points, and perhaps listing rails [more about that topic in the future I hope]).

Sometimes a listing cloth strip is woven between the post-lengths to quiet the sympathetic vibrations excited there.  With a good design this is probably a mistake since it reduces a great amount of tone reinforcement and perceived sustain, making for a rather dry sound.  With a bad design it may be necessary.
 

CHARACTERISTICS

The properties of the cloth needed will depend somewhat upon the way in which it will be applied (see below).  Overall, however, it needs to be absorbent(but not too thick) and “unstiff” so that it doesn’t deform string distances when woven between the string bands.  Unwoven felt cloth can be used, but does not usually hold up well to being repeatedly pulled through the strings, as happens when weaving it.  Woven cloth holds up better to this, but care has to be taken in selecting it since it is often stiffer than is desirable.  Ribbon with one velvety surface is sometimes recommended for weaving, but care must be taken when pulling through since it has virtually no “give” and will easily pull strings out of position and keep them there.
 
 
 
 

APPLICATIONS

Weaving strips of cloth (usually approximately ¼” to 3/8” wide) between pairs of strings seems to be the oldest, and most common method, to achieve the primary function of the cloth.  There are several approaches to this method:  1)  close weaving - where the weaving is done in parallel strips lying side by side, or 2)  open weaving - where the successive returns of the weaving cloth are spaced apart so that they zig-zag across the string band, or 3)  combination -  usually the bass is close woven to help control the damping of the heavier strings and the rest is open woven.

Another historical method, but with only about 100 years of precedence, is where a fairly wide strip of cloth (approximately 2” wide) is pushed down in between pairs of strings to form short loops above and below the string band.  This seems to have been most likely invented by Arnold Dolmetsch when he revived clavichord building at the turn of the century.  This has the advantages of being quick to install and remove, and of often allowing the instrument to have a louder voice than if it were close woven.  (Strange as this may seem, it has been confirmed by several people working independently that often more listing makes a clavichord quieter.  Perhaps since the tangent is not really a termination point for the vibrating string, but may act sufficiently as a fulcrum point so that mass added to the pre-length may actually have a dampening effect on the sounding length side.)  This poked through method does not allow the possibility of increasing the touch resistance as the woven method does.

Experimenting with the “more is quieter/less-is-more” discovery mentioned above, a couple of people and myself have developed a third method of applying listing cloth - as an underlay.  I am not aware of any historical precedents with clavichords for this, but it certainly is used with fortepianos and pianos.  With this method a strip of cloth is laid on top of the hitchpin rail underneath the strings.  If this distance is wide enough there is sufficient contact with the cloth for the string to be damped when the tangent drops, and enough contact with the pre-length even when it is being played loudly to damp that portion during play.  As the string mass increases descending into the bass, and the hitchpins transfer to the left hitchpin rail with insufficient space for enough cloth, some other method needs to be used to augment damping in the bass and low tenor.  If this underlay approach is added to clavichords not designed for it, care has to be taken that the cloth doesn’t lift the strings too much and reduce the down angle to the bridge.

The amount and method of applying listing cloth to a clavichord can often dramatically effect its volume, timbre and sustain.  Just because the present manner of listing is the way the instrument was sold, or is a way it was done historically, does not mean it is necessarily the best way to maximize a particular instrument’s musical potential.
 

Paul Y. Irvin, Oct. 28, 1996