"Breathing" of the air

Tom summarized is correctly. It is the medium displaced/excited in which sound is generated (vibrations generated by instruments)is what we hear. As a Kind of 'halo' around main notes- fundamentals and harmonics. Room acoustics is another entity that may impose its own signature on this 'halo' by allowing it to throughly develop or reduce it or make it dead. I am not sure but you would think you could measure the air disturbances as a change in air pressure- compression and decompression. I am no expert in this but an answer to this or confirmation to this would be to know how the anechoic (sp?) chamber is designed.

What exactly is anechoic chamber? a Room designed not impose sound signature due to room boundaries or and that would you still hear pure 'air' or 'halo' in this chamber?

Welcome to the Department of Redundancy Department.

"anechoic" MEANS "no echo". No echo means no reverberations or ambience. Anechoic chambers are built so that the frequency response, efficiency, etc. of a transducer/speaker system might be tested without any room interaction at all. Were you listening in such a room: all you would hear would be the source, and whatever resonances it generated from it's own body.

I see from your threads you live for the hate....

"Welcome to the Department of Redundancy Department"

It is not redundancy, just a bit more intricate details to explore and connecting dots further.

Thanks for clarifying anechoic definition..