Frustrating: you're hyper-focused on stage, enjoying your violin playing, the audience is in raptures, and suddenly a shrill squeak appears... The fear of a whistling E string can dominate your play and negatively influence your technique. Although there is no solution that can eliminate the problem on your instrument with 100% certainty, you can certainly reduce the risk almost to zero. Some technical knowledge about the materials from which a E string is made, the choice of string, small adjustments on your instrument and certain violin techniques can help you to avoid a whistling E string.
A little science...
When you stroke the strings with the hairs of your bow, you create a sideways vibration, called a 'Helmholtz' movement. If you look at your string at this moment, it seems as if the string moves from the centre of the vibrating part to both sides (figure 1). If you watch the string in slow motion, you'll see that the real movement is a lot more complicated, as shown in the video below (figure 2).
This is the desired movement, which produces a beautiful sound. Due to certain factors, it can happen that the string starts to vibrate in a different way, with a torsional (rotational) movement at about 4800Hz (an open A has a frequency of 440 or 442 Hz) (Figure 3). This is the moment that the whistling sound occurs.
figure 1: the optical illusion of the sideways movement of the string
figure 2: The 'Helmholtz' movement
figure 3: the torsional vibration, when the string starts to whistle
You have probably already noticed that the whistling sound only occurs with loose strings. That's because your fingertip on the string causes a high degree of damping. The damping determines how quickly the vibrations die out. Strings that start squeaking quickly usually have a low degree of natural damping, and not coincidentally, these are usually the unwound E strings made of (carbon) steel, whether or not plated with another metal. The torsional natural damping of E strings is very low, which means that, once the torsional movement has started, it does not stop...
Wound strings do not have this problem, as they have higher torsional damping. Their winding and construction ensures that the desired Helmholtz movement is much less likely to be disturbed. This is the reason why a wound E string is often the only solution to solve the problem completely. However, many violinists prefer the clear, open sound of an untwisted E string, and will have to find a compromise between the 'whistling risk' and the ideal sound image.
The E string and the materials used
Unwound strings are usually made of (carbon) steel. This material is very susceptible to corrosion. To counteract this phenomenon, they are coated with other metals, such as tin, chrome, gold or platinum. The quality and material of the plating also gives the string certain properties that influence the sound, response, volume, etc. influence the sound, response, volume, etc. Some materials give the string a very low torsional damping, others a higher one.
Stringings with a winding, which is something completely different from the plating or covering, are almost 'whistle-proof'. The winding of the E string is usually made of aluminium. The picture below summarizes the materials used, from low risk of whistling to (almost) no risk of whistling.
This list is compiled by experiment and gives a general idea of the E strings and the whistling risk, statistically speaking. However, it is possible that on your specific instrument and bow, a golden E string never whistles at all, and one with a tin plating does. So there are exceptions to every rule.
More about E strings can be found in this article.
A E string that has already solidly proven to be "whistle-free" is D'Addario's aluminium wound 'Non-Whistling' E string. If you like the brilliant sound of a gold-coated string, but are easily bothered by whistling, you might want to look at the variants with a platinum layer, such as those in the Thomastik Peter Infeld or Evah Pirazzi set. Also the Warchal Amber E string is designed to prevent whistling.
You could also try a lower tension of your usual string. Despite the fact that the momentum of the string is a somwhat bigger, the chance of an unwanted torsional vibration is much smaller.
Rosin, an underrated element
A bow without rosin is like a house without a door. An unrosined bow is unusable and will not produce any beautiful sound. Rosin is the key element and the bridge between the string and the bow. Anything that disturbs this connection, such as dirt or grease on the bow hairs, or too much rosin, will contribute to an increased whistling risk.
It is therefore worth experimenting with applying less - or more - rosin, or using a rosin that is slightly stickier. However, there are exceptions to this rule and you will have to find out by trial and error what works best for you. In any case, make sure you regularly wipe your strings with a microfiber cloth. A clean string has a higher reaction speed and will respond more adequately to the way you stroke it.
But it doesn't stop there...
Since a whistling E string often cannot be solved by a single adjustment, your luthier will be able to do several things to address the problem. For example, he can make adjustments to the bridge, the sound post of the instrument, the string grooves, tailpiece, fine tuners... Some adjustments will just make the problem worse, others might be a miracle solution for your instrument.
Practice makes perfect
Let's assume: you have a perfectly adjusted instrument and you feel better in sound and feel with an untwisted E string. The risk of whistling is very limited but still present. What can you do with your playing technique to get the string to your liking?
When you put your bow on the string and you start a new note from standstill, you will very rarely get a whistling E string as a reaction. However, in the case that your bow is in motion - e.g. when playing chords or string changes from the lower strings in the same region - and touches the E string from a certain speed, the conditions for the torsional vibration become very favourable. By slowing down your bow a bit and at the same time increasing the weight from your arm when arriving on the E string, you can counteract this effect. Normally this is a technique that is not very popular. An increased speed goes together with an increased pressure, we learn in the first violin lessons...
But for this particular problem, the counterintuitive can be one of the solutions. Musically, the result will be different, but better this than a disturbing, whistling E string, no? Having said that, often violinists are very careful when playing the E string and start transferring far too little pressure to the string. But to the same extent as great aggressiveness, being too hesitant can cause the unwanted effect...
The third element mentioned above is the contact point. By bringing the bow closer to the bridge on the E string, we give the string less 'room' to proceed to the unwanted torsional vibration.
Furthermore, you can experiment with other factors that affect bowing: hair tilt, the angle of your bow hair on the strings, the degree to which you tilt your violin, ...
If you have found other solutions yourself, please let us know! The violinist community will be grateful :)