Is there a way to supress the sound waves?

[pravin]

Hello friends.. whenever we walk near an hospital.. we can see that there usually sign boards like "no horn", but there are numerous sources of sound and noise apart from that.. which cannot be controlled. So, is there any method to neutralize the sound waves to reduce its decibel near to zero?

[wasi90lk]

i don't think all sounds can be (or should be) controlled, as that may be considered as dictatorship. if the noise is too little, i think that's not a problem.