Voice type in women. The size and development of adult lungs also changes what the voice is physically capable of doing. From the onset of puberty, the human voice is in an in-between phase where it is not quite a child's voice nor an adult one yet. This is not to suggest that the voice stops changing after puberty. Different singers will reach adult development earlier or later than others, and as stated above there are continual changes throughout adulthood as well. Treble can refer to either a young female or young male singer with an unchanged voice in the mezzo-soprano range.
Singing to vocal range, vocal weight, vocal tessitura, vocal timbre, and vocal transition points such as breaks and lifts within the voice. Other considerations are physical characteristics, speech level, scientific testing, and vocal registration. The science behind voice classification developed within European classical music has been slow in adapting to more modern forms of singing. Voice classification is often used within opera to associate possible roles with potential voices. There are currently several different systems in use within classical music including the German "Fach" system and the choral music system among many others. No system is universally applied or accepted. However,