Lol
The way I see Sound Release, is the ability for a ninja to produce and manipulate the vibration of air particles around him, creating waves of sound around himself. Well I interpret it as a powerful vibration, mainly in both lower and higher frequencies, that you can create yourself. I also want to point out that you always need a medium to produce sound. The medium can be anything, even your vocal cords are a medium to produce sound. This particularly makes sound one of the biggest, most deadliest elements. You always have a weapon nearby to produce it with. This means that you can simply make/release sound without the need of an instrument.
In terms of sound you get three types of techniques: those which produce destructive damage, those who hinder your body senses (most of the time) and last but not least those which serve as medium for Genjutsu. Let's start with those which produce destructive damage. The destructive properties of the Sound Release always rely on the wave vibrating at the same frequency than the innate particles of a certain substance, which then disrupts it. By matching the sound we produce with the core of the substances, we can break those substances apart without any trouble whatsoever. For the ones that hinder your senses I can give you an example from the Sound Release techniques, the Ringing Madness. It basically does damage to the ear drums. The technique itself continues to disrupt the person's hearing and his ability to think clearly. Likewise I want to talk about my favorite part of the sound element. As I have already mentioned you can combine the Sound Release and Genjutsu to create powerful illusions. But how exactly does this work? The Genjutsu properties of the Sound Release of course rely on the same mechanism that translates the sound hears. The chakra transported in the sound release techniques lodges to the brain and is translated in whatever illusion the user performed.
I assume you also want me to explain to you what a wave is. It is basically the basic for almost everything sound related. It is actually the process of energy moving from one point to another. There are two known kind of waves, mechanical and electromagnetic waves. The main difference is that mechanical waves need a medium to travel through, while electromagnetic waves don't, simple as that. From reading a lot of fights in which sound was used I came to a conclusion, that while being used mostly through air, sound moves fastest through earth. Most people use it directly through the air which is not good because wind being the natural strength against sound, should make you realize that you should use sound through other things than actually using it through air. Sound can be also used through water, correct?
I also have one question, sensei. Is there any other counter other than Wind Release against Sound?
Sound is weak to wind because it disrupts the oscillation of the sound frequencies dispersing them. That is the only element that can completely stop the sound waves. Other elements such as wood, earth, water, solids, can dampen the sound but never completely block it. You see, each object has it's very own resonating frequency. If you send a sound blast at an earth tech while the sound has the resonating frequency of the earth, the earth will shatter. You can channel sound through most mediums.
Here is a little scientific stuff that McRazor taught me, it might help.
First of all, a frequency is measured in Hertz. A frequency in theory is how many waves pass a certain point in a certain amount of time. So, basically, the lower the interval, the higher the frequency.
Now, the cool thing is, adjusting the frequency. A higher frequency is a higher pitched tone, while a lower frequency is a lower pitched tone. If you listen to music and hear the bass, the frequency is lower. You can also feel it in your body a lot more than high frequency tones, because generally those are harder to perceive in the first place. The neat thing is, that this allows us to alter the effects of sound techniques by altering the frequency. That being said, you probably see how versatile sound actually can be, and how it can create different effects. Even if you can't hear something, the sound waves are still there and can still have effects on your body.
Substance it moves/passes through
Now, realize that sound can move through any medium. Don't let anyone tell you otherwise! Though we needs some sort of limitations, and it's reasonable to say wind is a good counter to sound if it can be seen (doujutsu) or heard, but at that point it might be too late (depending on how a technique is used and how the effects are). Earth, however, depending on the situation (and the level of understanding of the usage by the opponent) can be a devastating counter as well.
Now, look below:
-Speed of sound:
solid > liquid > gas.
Sound moves fastes of all through solids. Generally, this is because the particles and atoms in earth are more tightly packed than they are in liquids or gas. So, the closer the atoms/molecules, the faster sound moves.
- Elastic properties
There is a catch in between different solids. Sound moves faster through rigid solids (i.e. steel, iron) than other things like jelly. This is because solids that are rigid generally mean that the atoms and molecules have a much stronger force of attraction towards each other than in other solids. This is because of the fact that, once moved, they move back to their original position/form more quickly (and thus resulting in a much higher vibration speed). jelly in this case has much weaker attraction between the molecules, that's why it's so "elastic" (not to be confused with elasticity like rubber), and much more flexible.
- Density
Next to this, there is the density. Now, more dense substances = more mass. More mass=bigger molecules. Because sound is based on kinetic energy that travels from one point to another, moving through denser objects means it has to use more energy, seeing as it has to move (vibrate) larger molecules. This however is used for substances with the same elastic properties.
To explain this take two examples with nearly the same elastic properties. Gold and aluminum (Gold = 10.8 psi; aluminum = 10 psi). While they nearly have the same elastic properties, gold is much denser, so it will travel faster through aluminum than gold.