What is the state where the initial sound produces by the vibration of the vocal cords is made loud by air chambers known as resonators?

The state you are referring to is known as "resonance." In vocal production, the initial sound generated by the vibration of the vocal cords is amplified and enriched by the air chambers in the vocal tract, including the throat, mouth, and nasal passages. These chambers act as resonators, enhancing the quality and volume of the sound produced. This process is essential for producing clear and strong vocal sounds.