Hi is there any possibility that you located between 2 sound sources and u hear nothing? as we know 2 wave in opposite direction will destroy each other...
Yes, this is exactly how noise suppression headphones operate, works like charm, http://en.wikipedia.org/wiki/Active_noise_control
When you get two waves to interfere with each other, then there is no reflection. Usually, you use a quarter-wavelength reflection to get this result. The energy is usually passed off as heat, i imagine, but 4 W of heat is like a calorie per hour.
Two waves travelling in opposite directions will add one over the other, so you will get some sort of standing wave which is set by the phase difference between the waves. In this case, the sounds still exist, and will escape out of the thing.