be noisy
噪 centers on producing loud, chaotic sound: being noisy, clamorous, or causing a din.
噪 combines 口 (mouth) with 喿, which likely contributes the sound and the idea of noise or clamor. The exact historical development of 喿 is uncertain.
A mouth 口 beside the noisy-looking 喿: imagine many mouths chattering at once, creating a loud, chaotic noise.
For ソウ, picture a loud, noisy saw cutting through wood: saw -> ソウ, and the sound fills the air like the clamor of 噪.