The amplitude of the sound pressure.
volume
An amplifier amplifies the input voltage. That gives you more volume.
A sound box alters a instrument's tone, it doesn't affect volume.
It is important to have the right sub woofer enclosure because different enclosures can affect the quality of the sound. Sealed boxes offer better sound quality but you will sacrifice volume. Ported boxes offer better volume, but the sound quality is not as good.
volume
The amplitude of a sound wave is the same as its volume.
Amplitude is intensity. It refers to the strength of a sound wave, which the human ear interprets as volume or loudness and if you decrease the amplitude you also decrease its intensity.
The difference between pitch and volume is pitch is tone, and what a sound is, and volume is how loud a sound is.
"Volume" is a term referring to how loud a sound is to humans and animals. Most entertainment devices that use sound have a "Volume Control", typically labelled, "Volume". Volume is not quite the same as "Loudness", by the way.
Answer is by sound waves
To make low volume sound into HIGH volume sound.
Volume is to make sound get louder or softer.