If you were to pour water into the sound hole of an acoustic guitar, the sound produced would be significantly dampened and muffled. Water would interfere with the vibrations of the guitar's top (soundboard), which is responsible for producing and amplifying sound.
When you pluck the strings of an acoustic guitar, the vibrations are transmitted through the bridge to the soundboard, causing it to resonate and create sound. The sound hole allows the soundboard to vibrate more freely, projecting the sound outward. However, if the sound hole is filled with water, the vibrations would be absorbed and disrupted by the liquid.
The presence of water in the sound hole would impede the movement of air within the guitar body, which is essential for producing the characteristic resonance and tone of an acoustic guitar. Consequently, the sound produced would be dull, muted, and lack the typical richness and projection associated with an acoustic guitar.
It's important to note that pouring water into an acoustic guitar can potentially damage the instrument. Excessive moisture can cause warping, swelling, and other structural issues, affecting the playability and sound quality. It is always best to keep your guitar in a dry environment and avoid introducing liquids into the instrument.