If mass and tension of a vibrating object are held constant, there will be one frequency at which it vibrates best.
But in time the problem becomes increasingly compelling. An inability to get preferred jobs or dates drives the now young man to seek professional help.
A speech pathologist may be able to correct the voice in 30 minutes, but it may take a year of counseling for the young man to accept and use the "new" voice in public. But back to mass and tension.
What happens if the mass of a vibrating object is held constant and the tension is not changed?
Under these conditions there will be one frequency at which that object vibrates best. That frequency is called the Natural Frequency.
The farther away in frequencies an object vibrates from its natural frequency, the more intensity it requires to produce a desired loudness.
Take, for example, the person who speaks habitually at a higher pitch than their natural frequency.