Let's learn about static, part 2

So, we explained static electricity and in doing so it really sounds like it is just an unavoidable nightmare to deal with. Unfortunately, that is true, and it doesn’t really get to much better. As we briefly just mentioned in part 1, static electricity can even happen through what is called electrostatic induction, or what is also called electrostatic influence. This really makes the issue of static build up much larger of a problem. Additionally, it is not even the buildup of static electricity that is wreaking havoc. Although static electric buildup is the primary concern and is the result of a great deal of interactions around us, it is the discharge of this static electric buildup that is what we hear and ultimately effects our listening experience. In this part we are going to explain what electrostatic induction is and how it is different then Triboelectric charging (explained in part 1). We will also discuss the air around us, from the dust particles to conductivity. Lastly, we will explain how static discharge works, how humidity can affect it, and how everything from part 1 and part 2 is going to help us better understand the available methods, tools and best practices to fight static (part 3).

Let’s look at static induction, or also called, static influence. This means that an object can actually become charged just by coming close to another object that is charged. The objects do not have to ever make physical contact with one another. Further analysis of this phenomenon means that if you have an object like a conveyer belt in which generates a lot of friction and you place a box on that conveyor belt, as the box moves along the conveyor belt it will cause a substantial charge buildup on the box. Now the box would have a net electrical charge and an electrostatic field present that could then in turn transfer to anything placed in or around the box. This is very important to understand because it is the reason for one of the largest effects that static electricity has, the attraction of dust. As dust moves through your house it can become positively charged or negatively charged, depending on the surface or object it may come in contact with, or even just come close to an existing electrostatic field. Another aspect to understand is that if dust is generated from objects that are electrically charged then the dust itself will also be electrically charged. This also means that dust in your house can behave differently from day to day and that while certain materials may not cause an issue between themselves, they could cause an issue by attracting dust. Additionally, the dust in your house is most likely to become charged by the friction it has with the air in your house. That’s correct, as dust collides with air molecules it actually causes friction. This is the reason that we see dust being attracted to almost everything in your house. The larger amount of dust in the air, the larger amount of dust that will cling to objects and materials in the room. 

Up until this point we have covered how and object or material around us can become charged as well as the notion that a large number of objects, materials, and even dust around us already may have a charge, or better described as electrostatic potential. So, what’s the big deal with some charged particles?  Aside from these charged particles attracting dust and other charged particulates, it also can discharge its energy (the other larger problem).  This is defined as part of its electrostatic potential and is a quantifiable amount of energy these charged particles have. This energy is stored, typically on the surface of an object or material, and will continue to build up until it has a path to ground or a larger charged object. This attempt to rebalance itself is referred to as static discharge and we commonly can see it or feel it in the form of a spark. The amount of this discharge is highly dependent on the capacitance of the object, material, or person holding the charge. In other words, the object, material, or persons ability to hold a charge which will vary. The occurrence and amount of discharge is also dependent on the number of free electrons and the formation of a conductive channel. These dependencies are important as they provide insight as to how to effectively manage discharge and reduce the issues it may cause on our audio system. In example, let’s look at the air in our house and discuss as to why we may notice electrostatic discharge certain times of the year versus others. One of the major dependencies for discharge to occur is the conductive channel. As we mentioned, a large electrostatic potential will sit on the surface until it finds a path to ground or transfers to a larger or more charged surface. That path is called the conductive channel. As we are dealing with an electric charge it needs a conductive conduit to get from point A to point B. We know that point A is where the potential electrostatic charge is while point B can be anywhere that is going to offer the opportunity for the charge to move to. The air in our house can offer such a conductive path and can change day to day. One of the largest contributing factors to this is humidity.  In the summer months or in warmer temperatures, especially without the use of forced are or other supplemental heating systems, the air in our house will be more humid. The opposite for colder months as the air is less humid which is why we characterize it as dry air. The dry air is made worse by the addition of supplemental heat and when we live in a house that has forced air (forced air also will spread that dust all through your house too). The more humid the air, the more conductive. The less humid the air would then in turn make the air less conductive. However, it works a bit opposite to the way you would most logically think. One would probably tend to say that more conductive air would be where more static discharge would occur, and vice versa. However, it is more humid conductive air that is less likely to cause issues with electrostatic discharge. See, more humid the air allows that increase in conductivity to more evenly distribute the excess charge limiting the conductive channel. The less humid the air means that the conductivity is low enough for the static discharge to go directly where it wants to, with little dissipation (a precise conductive channel). 

Let’s try to sum up the discussion in Part 1 and 2 so that we can really understand Part 3, in which we will dive into the ways to eliminate and reduce the issues caused by static. 

This is what we know so far. We know that static electricity is caused by the imbalance of positive and negative electrons. Certain objects and materials also have an inherent propensity to either give up or gain these electrons. When objects or materials that have opposite propensities come in contact with one another, inductively or triboelectrically, they want to try to balance these electrons. With the separation of these materials or objects, which would include friction, an electrostatic charge is created. The object or material that has a propensity to lose and electron would then have a positive charge while the object or material with the propensity to gain an electron would then have a negative charge. These charges are typically held on the surface of that object or material and will attract other objects, particles, dust, and ions, that have the opposite charge. Thus, if a vinyl record has been caused to have an electrostatic build up (which would be negative) it is more likely to attract positively charged dust particles. This occurs like a magnet and could equally happen to positive charged objects or materials because dust can become either positive or negatively charged, through a process called electrostatic induction. Once an electrostatic charge is present it can be determined and quantified to have an electrostatic potential, which is the amount of energy that charge contains and could release. The release of this charge is called electrostatic discharge and occurs as a further attempt for the charged object or material to balance itself. This is very common in the way of a negative charged electrons (cathode) wanting to move towards the positive charged electrons (anode). As discussed in part 1, that is the basis for how a battery works in a contained system. Objects that have either an excessive positive or negative charge can also regulate and balance this charge by a process called grounding. Through grounding a positively charged object or material would gain an electron from the ground to the object or material, thus neutralizing the charge. On a negatively charged object or material the electron would travel from the negatively charged area and travel to the ground, also neutralizing the charge and then would have a net charge of zero. We define this net charge of zero as no longer having electrostatic potential. Additionally, it is important that grounding electrostatic charges should not be confused with the ground for your turntable (research Faraday cage and electromagnetic shielding). If an object or material has an electrostatic potential present it is going to want to either regulate it through a ground (as mentioned) or through a different conductive channel. This can also include to other more charged objects or materials as well as the air around us. As these currents discharges you will find that in less humid air (mainly 40% and below) the charge can more easily reach is destination as the air does not have the proper characteristics to dissipate the charge.  When these electrons leave and travel through its conductive channel they will collide with other electrons (can even be dust) forming new additional electrons. This trail of electrons and conductive channel will grow towards its destination (anode) and will create a conductive bridge. This bridge allows for the rapid discharge (flow of current) which we see in the form of a spark, and the conductive channel breaks apart thus eliminating the net charge. 

In our audio system we have key principles of static electricity that cause negative effects and you are probably thinking, “well heck, I could have just read the paragraph prior to this and started there”. That may be correct for some, however, we really feel its important to understand these principles. In doing so it would allow you to evaluate your audio system and the problems you may be having with a much broader spectrum. In Part 3 we are going to discuss the individual situations that these various effects cause and look at the logic behind the products designed to combat them. Knowing the differences in materials, how static is created, how it behaves, and how it discharges will also help you better understand these products. The purpose of doing so is to make sure that you can attack or prevent a concern using the right tools for the job and continue forward following the best practices.   

More to be updated 3/03/22  (Part 3)

How do all these interactions play a part in your audio system?

Ways to manage static and the principles behind the products we use.

Conclusion