6 Needham Avenue, Chorlton-cum-Hardy, Manchester M21 8AA, U.K.
Phone & Fax. +44 (0) 161 881 8134 ; proprietor: Dr. Ephraim Segerman [USA]
e-mail: email@example.com ; on internet: http://www.nrinst.co.uk
THE BUZZING OF WOUND STRINGS
I: THE PROBLEM
Buzzing occurs in traditionally-made metal-wound-on-gut strings (like those we make at NRI) when the metal windings are loose and they rattle against the core and especially against each other. The metal wire is wound very tightly over the core when the string is made, the wire tension being so great that it presses grooves into the gut core. When a string is put on an instrument and tuned up to pitch, the tension stretches the core elastically and it gets a bit thinner. The windings ride in the grooves as the core stretches and so get separated a bit, with the diameter of their turns decreasing slightly. The core diameter decreases more than the winding diameter, creating some looseness. Some of that looseness is taken up by relaxation of the gut surface that had been compressed during the winding process. The remaining looseness causes a soft buzzing of the windings rattling against the core. As long as the windings are confined to their grooves, so that the much more noticeable buzzing of windings against windings is prevented, a sound results that is considered normal for wound strings. Greater looseness of the windings that will allow windings to slap against windings can result from various circumstances. These can be:
A. The core becomes thinner than it would normally be when just tuned up. This can be because:
1. The gut is dryer than it should be. Gut gets thinner with lower moisture content and thicker with higher moisture content. Its moisture content depends on the relative humidity of the air surrounding it. We dry the gut almost completely before winding, but it picks up some moisture from the air during the winding, ending up with a moisture content that would be in equilibrium with an atmosphere at about 30% relative humidity. So a normal string can buzz if it is played in an extremely dry atmosphere of considerably less than 30% relative humidity. This is very rare. Such buzzing would disappear when the humidity becomes more normal.
2. The gut has thinned because of inelastic stretching. We pre-stretch gut cores at playing tension for about two weeks before winding on them. The criterion for ending the pre-stretching is that we cannot notice any further stretching on successive days. This avoids the wound string experiencing the rapid stretching of gut early in its life. But gut does continue to stretch slowly as long as it is under tension (thinner gut, being closer to its breaking tension, stretches faster than thick gut). This will eventually lead to the string becoming buzzy. There is no way of avoiding this process except by detuning strings when not in use.
B. The windings have a cylindrical diameter that is greater than it would normally be. This can be because:
1. The metal temper was wrong, being too springy to let it wind tightly enough. We check this carefully on every reel of winding wire that we use.
2. The tension put on the winding wire during the winding process was not great enough, resulting in the grooves in the gut made by the wire not being deep enough. The most important aspect of the training of a string maker is to learn to feel the appropriate tension with which to feed each type and diameter of winding wire, which very often is the maximum beyond which the wire stretches by necking and then breaks. Our string makers are well trained and quite consistent.
3. After the string is made, high relative humidity swells the gut core, which stretches the windings to a larger diameter. At this high relative humidity there would be no string buzzing, but when the humidity subsequently lowers and the gut core contracts again, buzzing occurs. This is by far the most common cause for buzzing. The spell at high relative humidity could happen in the obvious way of being exposed to wet weather or the not-so-obvious way of being enclosed in a space at normal temperature and humidity which gets cooled down, reducing the capacity of the enclosed air to retain moisture,and thus automatically increasing the relative humidity. Following are various aspects of string care for avoiding such buzzing from humidity cycling:
a. We seal the string in an air-tight plastic envelope immediately after it is wound. The plastic is highly resistant to the passage of water vapour through it, but it can't be completely so. After weeks in a very high humidity environment, it is possible that enough vapour will pass through the plastic to swell the gut sufficiently to lead to buzzing. If this occurs, it is after we send the string out, since we are careful not to let the humidity get high where we store our string stock.
b. If one opens the string packet before it is needed for the instrument, it becomes much more vulnerable to become buzzy when it is finally used. This should be avoided.
c. After the string is put on the instrument, one can avoid it experiencing high humidity by not taking the instrument out of its case for extended periods of time when the humidity is particularly high. The case would have to be fairly air-tight so the high humidity air cannot get in. The case would also have to be fairly insulating thermally so that its contents do not have the chance to get very cold. Leaving the instrument out of its case in a room that is heated during the day but not at night is particularly dangerous. The relative humidity shoots up as the room cools at night.
d. If a string has become buzzy, one might try to correct this by tightening up the winding. This can be done by detuning the string and turning the peg so that the string goes straight through it (with no turns on it). Grasp the string with the fingers, one hand on each side of the peg. Roll the string between the fingers of both hands as much as one can in the direction of tightening the windings. This is anti-clockwise when looking down the string towards the bridge. While keeping the string in the maximum-rolled condition with the hand on the vibrating side of the string, use the other hand to turn the peg to tune the string up again, thus locking in the new twist. If successful, this will only cure the buzzing until the next time the string is subject to high humidity.
e. If one can't avoid high humidity circumstances, buzzing can be avoided by keeping the string continuously at high moisture. For this one must keep the instrument in a case with a humidifyer included. There are commercial humidifyers sold both for this purpose and for preventing the cracking of the instrument wood which can occur at low humidity. A traditional method involves keeping a piece of cut fruit in the case with the instrument.
C. The grooves in the gut that the windings ride in can be damaged mechanically by handling.
1. This can occur by binding of the winding wires by defective grooves in the bridge or nut when tuning up.
2. It can also happen by bending the string too sharply any time between its being made and its being installed on the instrument. That could be at our workshop before the string is packed, or with the player after taking it out of the packet.
D. Often buzzing has been found not to result from any fault in the string. Though induced by the string's vibration, the buzzing can come from:
1. a badly fitted bridge, where parts of the feet vibrate against the soundboard,
2. a badly cut nut, where the string is supported on the pegs-side of the nut and slaps against the bridge-side,
3. a loose bit of string in the pegbox, vibrating against the pegbox or peg, or
4. bits of the instrument's body that should be glued together are unstuck, and vibrate against each other.
II COMMERCIAL CONSIDERATIONS
In normal commercial relationships the party most likely to be responsible for a product becoming defective pays for its repair or replacement. Our policy has been to take financial responsibilty for replacing strings if they buzz when they are first put on the instrument or very shortly afterwards, and not if it starts after that. The areas in which we can possibly be at fault are covered in A.1., A.2., B.1., B.2., B.3.a., and C.2. above. In each of these possibilities, the buzzing would show up immediately on first tuning up of the string. Because of our controls on string production, we believe that most of the time that the string buzzes when first tuned up, the problem has been in the way that the string has been stored or handled by the customer (mostly B.3.b., C.1., or C.2. above), but we give the customer the benefit of the doubt and replace the string without charge or quibble. If a buzz develops within a week or so after the string has been put on the instrument, we are quite convinced that the problem is not of our making. Yet we understand the disappointment and annoyance of the musician and take financial responsibility while offering advice. If the buzzing happens after that we will offer only advice. Otherwise we would have to raise prices to cover our losses, which would unjustly penalize the customers who take proper care of their strings. We hope that the explanations given here will increase understanding of our position.
III THE MODERN ALTERNATIVE
In the middle of this century a new kind of string construction was invented to avoid the problem of buzzing. In this construction there is a layer of highly compressible plastic floss placed around the gut core before the metal is wound on (the plastic is either wound on or stretched on as a stocking). This prevents the metal winding from making grooves on the gut core and the floss allows the metal windings and the core to freely slip past one another. The metal windings, which are pressed against one another on the string in the packet remain in contact as the string is tuned up to pitch. This prevents the harsh buzzing of windings slapping against windings. It also makes it unnecessary to make the string grooves in the nut and bridge freely slipping. The softer buzzing of the metal windings against the core would be enhanced because of the greater looseness, but this buzzing is cushioned by the plastic floss. The vibrational energy lost in this cushioning reduces the brightness and power output of the string, giving it a different tone colour than a traditional string. This is a price that modern players are willing to pay for insurance against buzzing and the increased pitch stability that this construction provides. The latter is the case because the windings, being against one another, provide an excellent barrier against moisture exchange between the atmosphere and the gut core. An additional advantage of this kind of string construction is that flat metal windings of ribbon shape can be used. The resulting flat surface makes a greater area of contact between the string and the bow hair, quickening response time. Without the plastic floss to dampen and cushion vibrations, ribbon windings on gut always lead to immediate buzzing.
Strings of this modern type of construction are the mainstay of quality strings in the world of modern bowed stringed instruments. The world of early music is divided concerning their use. Those who follow the original philosophy of the movement - that one should use equipment as close as possible to that originally used at the composer's time to most faithfully fulfill his expectations of performance when he wrote the music - shun these modern strings and go to the trouble of avoiding buzzing using traditionally-made strings. Those who consider early music as a repertoire and style in which they they want maximum freedom and convenience in expressing their musicality will use any innovation that they can get away with, including modern types of strings, that avoids distraction from their creative intent. Many (if not most) are confused about their philosophy and avoid the issue, just wanting to get on with their jobs of being musicians. The early music audience is similarly divided between those who expect historical accuracy, those who are only concerned with the attractiveness of the music offered to them, and those who are unaware of any problems in expecting both.
Those musicians and listeners committed to maximum historical fidelity to the composer's intentions are the true modern innovators, because their philosophy is unique to this century. The others who focus on optimizing the act of communication between performer and audience are following a philosophy that has been traditional throughout the history of music. The only aspect of this situation that we are judgmental about is that we deplore the deception of lack of openness and honesty practiced by very many performers, to whom historical accuracy is of secondary importance, when they are trying to broaden their appeal to include listeners who expect that authenticity.