One of the fundamentals of singing is to understand that a singer can sing only but so loud or soft at any given moment. This is very important to not only understand as an intellectual concept, but must be internalized so that we “feel” what is a healthy volume.
First, singing softly. In order to sing soft correctly, there must be quite a bit of muscular strength developed as well as a very precise coordination between the closer and stretcher muscle. For it is these precise graduated adjustments from more cord vibrating in depth to less cord vibrating in depth that produces exquisite soft singing. Attempting to sing too soft too soon in the voice training process can cause the singer to feel constriction in their throat due to inexact coordination.
Next, singing louder. There is a way to have more volume without yelling. As the two main muscle systems and the cords themselves are developed, they get bigger and stronger just like our muscles at the gym do when we workout. As these muscles coordinate, then they do not waste oxygen, but rather turn it all into awesome sound waves. As the vowel is formed properly and is the correct size and shape for the pitch being sung, then we have all of these ingredients combining to give us what could be called an amplifier in our throats. Not only do we have an efficient vocal instrument built that produces a full-bodied sound, but we also have an amplifier or “resonance” as a byproduct of all the parts lining up correctly and being in balance with one another. Thus, we do not have to push and press to get louder.
Now, at any given moment we have a certain level of strength and balance. If we become imbalanced because of forcing, then we drop it all, and can hurt ourselves. If we try to add volume beyond what we can do at the moment, then it is like lifting too much weight at the gym, and then we risk severe injury especially as we repeatedly lift excessive weight without having enough actual strength to do so.
So, it is important for the singer to be guided by a voice teacher to feel what is the maximum and minimum of volume that is healthy for the singer at any given moment along the vocal journey.