While I feel amalgamate's post is the answer you are looking for, I can offer some suggestions to objectively improve/compare your singing volume.
Seek one-on-one vocal instruction. While singing in a group you learn to focus on blending your voice with others, this could definitely deter your ears from remembering what your voice sounds like and could definitely lead to volume issues. Every choir has people who do not sing loudly enough - rest assured your situation has a solution. In choir, the focus is pitch and blend. 40 other voices singing different pitches at once would wig anyone out.
Remember, our ears are on the sides of our faces - not directly in front of our mouths. People sometimes find the sound of their voice on recordings unpleasant because they are not used to hearing it that way before. Well...there is no way they possibly could. The nature of how your ears works changes the vary EQ of your voice! So too does their position!
By going to a vocal instructor you will be given the opportunity to hear your voice by itself. Singing in a choir or with instrumentation behind you is not the same! In this element you are forced to truly hear your voice. This gives an instructor an opportunity notices you naturally singing too softly (for anyone to hear), maybe then he/she can offer some suggestions to improving your tone. Most of the time this involves
- Proper technique in singing/breathing from your diaphragm
- Vocal exercises to warmup/cool down so that you can sing comfortably at full volume
- Tongue twisters to properly form certain vowel/consonance sounds to ensure clarity and less mumbling (How now brown cow)
Is there a good way I can measure myself and see how my volume
compares to a typical singer, similar to how I can measure my vocal
While I understand your intentions, a word of caution. By comparing one's technique or practice habits to someone else, one can derive great benefit. However, there are variables out of our control. I believe singing volume to be one of them. Is your case hopeless? Of course not! Might you need some help? Perhaps.
Other ideas. Keep the same microphone settings and
- Record your voice without accompaniment
- Record your voice with accompaniment
- Record your voice in choir
Compare all of these to each other. Are you quieter solo than with a guitar? Perhaps you are just focusing on nailing your pitches. Can you pick out your voice in a choir? The same thing could be said for all these situations.
Pitch || blend || tone > volume (within reason)