To best answer this let’s first look at an answer to another question!
What is music?
Heinrich Heine a journalist, an essayist, and one of the most significant German romantic poets in history says that:
1. Its domain is between thought and phenomena.
2. Like a twilight mediator, it hovers between spirit and matter.
3. It is related to both, yet differing from each.
4. It is spirit, but it is spirit subject to the measurement of time.
5. It is matter, but it is matter that can dispense with space.
6. Where words leave off music begins.
I think that after some consideration most of us can agree with Heinrich Heine’s description. Line 5, “It is matter, but it is matter that can dispense with space” is of great importance in this article because we’ll find that it parallels the laws of physics that governing how sound travels through our air space (acoustic).
Acoustics, like all media types, fall subject to this law of physics called “Inverse-Square”:
“…any physical law stating that a specified physical quantity or intensity is inversely proportional to the square of the distance from the source of that physical quantity.“
When we begin to understand this law it becomes clear that all audio sources do in fact have a single point of origin and we quickly begin to answer our first question, “Is wider better?”. Once we widen our image to the point where we cross the threshold from perceiving a single source to where we perceive two separate sources, we introduced conflict and confusion into our mix. At the point we cross this threshold our mix image changes from stereo to what has been referred to in years past as a “2 mix”. Depending on the content of these two sources we find opposite energy types that oppose each other to the point where they will with variances defeat each other to some degree.
I have found that in the case of 2 track “stereo” sound (most common music file type today), some mixes that come to me for mastering contain varying degrees of “dual but opposing sources.” This opposition adds up algebraically therefor creating a self-defeating phenomenon when it is reproduced with our common audio loud speakers. This type of reproduction system is found in most venues (theaters, clubs, churches, cars, home stereo systems, etc.) is also subject to the law of acoustical physics enforcing the fact that opposite energies destroy each other with widely varying results. In addition what is left in the center of the mix is pushed back and noticeably dulled or becomes smeared losing low level detail.
This type of confusing conflict can be demonstrated with a simple experiment. Let’s take two people standing equal distance apart and in front of us. One person on our left and one on our right as they both speak at the same time. When this audio energy makes its way to our hearing we reach a point fairly quickly where listening fatigue will overcome us and normally we’ll react in one of two typical ways:
1. We’ll simply quit trying to listen and ignore both speakers or
2. We’ll put a stop to it and insist that only one talk at a time so we can understand it.
Remember when we were back in school and the class was asked a question by the teacher and many times two or more students wanted to answer. Typically the teacher would pick only one person at a time to speak, right? Having everyone answer at once would just be confusing, frustrating and tiring, and most times the answer gets lost in the chaos.
With music mixing, I find this type of phenomena often occurs when we are working with stereo images and trying to achieve something special that makes it sound cooler and/or more spatial. We attempt to achieve an effect that we sometimes call a ‘wider stereo image’. The result of this widening when it exceeds a point is the same as in the classroom if the teacher allows multiple students to answer at once, or in our experiment when we tried to listen to two people at once. For the listener it is frustrating and confusing, and a quick onset of fatigue will come after a few moments of being exposed to it. The period of time for this shut down to occur varies with each person, somewhat dependent on age but affected by other conditions as well.
Sometimes in the “Mixing” and/or the “Mastering” process we, as engineer/producers, may want to increase the perceived left to right distance of one or more elements in our mix, creating the illusion of a wider sound stage. A popular way of doing this is by increasing the out of phase content on the left and right sides of the mix so it gives the perception of a, “wider stereo image or mix.” That’s great and it works because that is precisely what happens: as a sound travels away from its source, the phase shifts in opposite directions between the left and the right thus creating a sense of depth, distance and directionality.
This works fine as long as we do not cross the line that opposes this “Inverse-Square” law of physics. If we cross that threshold we realize widening past that point is indeed an unnatural effect that will do disservice to the purity and enjoyable nature of the listening experience. Once we cross that line, we find that the law of physics for realistic sound is unmovable and morphs from friend to foe. The law remains and the math holds true to its commission. Basically the law of physics wins and the music loses, leaving the music sounding unnatural and somehow “wrong”.
Take the old example of dropping a pebble in water. Many have used this visual to demonstrate how sound travels, propagating in similar pattern. Each ripple is one long arch unbroken from left to right and so should our audio spread be, unbroken in the center. Once they are broken they lose their origin/source and thus their reality is diminished.
Let’s discuss a little more about how a stereo image is perceived. Consider that a stereo image is a wall of sound traveling away from its source and that while it does in fact have a left and a right dimension it just as equally has a “depth” or a front and a back, a 3rd dimension or “distance.”
In some cases I’ve run into this phenomenon portraying a lie due to it crossing the threshold of reality. The reality is that now the sound after traveling much further on the sides is louder than the direct sound from the source itself. Remember what Heinrich Heine said above when describing music, “It is matter, but it is matter that can dispense with space.” Well then the farther sound has to travel the more it will dispense or become less intense. In other words, volume decreases if distance increases. Newton’s law of universal gravitation displays the law of inverse-square just as do the effects of electric, magnetic, light, sound, and radiation phenomena.
For the sake of reality, our stereo image should agree with the laws of physics or our human body/brain simply handles it as noise, frustration and confusion, and we quickly suffer the on-set of listening fatigue. When people listen to music that is unnaturally widened they will sooner or later experience that same phenomenon entering a state of non-listening or shut out.
In a nutshell, when we over exaggerate the width of a stereo image we get a piece of music that falls short of conveying reality for a music enthusiast and will prove to be disconnecting for our listeners. They will naturally listen to our music less (if at all) largely because of that confusion and/or fatigue. Over widening has a short term effect on humans that maybe cool for a brief period of time, but this music will experience a shorter listening time for the exact same reason as our experiment of two or more people talking at the same time.
To help with determining where this line is, I have conveyed to many mix engineers in my career as a mastering engineer that the “mono” function in our mixing environments is a critical tool in our arsenal that turns on the light. This simple tool is possibly more powerful than all our plugins or devices when it comes to measuring how well our music will translate to our listeners. A routine “mono” check will reveal to us whether or not we have indeed crossed the threshold into confusion and unbelief or multiple sources.
If we simply listen to every element in your mix as we engage our mono function no matter how wide to the left or right it may be, it should simply (and without any change in volume or equalization) snap to the center. Some of today’s audio monitor controllers can not only provide a mono signal with the touch of a button but also reverse the phase on one speaker. This allows us to “A/B compare” both the center summed and the sides summed in the center. In addition it allows you to compare each signal to each other for a good ratio balance. Typically the content that you hear in the side sum (mono with phase reversed typically on the right speaker) should be no louder then they are in the center sum (mono). If the side sum is louder then the center sum we would be defying the law of physics.
Isaac Newton’s discovery of the Law of Inverse-Square will hold firm and if we are true to our music and want to give the best experience to our listeners, we should understand and heed this law of physics. This truth is in total control when we use natural acoustic as our delivery media, and that is the case if our music is playing through any type of loud speaker system.
In this way we’ll provide a single sound wave like the wave produced when we drop a pebble in the water. A wave that has a single source but propagates outward from that source will agree with the “Inverse Square Law” of physics, and therefore sound real and not artificial, not confusing or fatiguing.
Now I think we can all answer the first question! Is Wider~Better?