In serious 2, I focus on the relationship between Echo and Space. Same as the warning system in the human brain, people could measure the speed of echo in order to perceive the space. The auditory system continually tracks and updates a representation of the statistics of the environment, consistent with its role as an early warning system.
Then installations are positioned with different microphones and will be incorporated into one sound system. I use a contact microphone to acquire the sound signal, then I transfer those sound signals into a virtual sound message by the usage of audio interface. Each single part of the installation has been set to have various echo effects (e.g. Opera House, Corridor, Hall, Bathroom). When the audience interacting with the installation, at the moment the sound is being created, there will be an analogy formed between the virtual sound signal and the physical vibrations.
Echo effcts 
Echo effets
The first layer is the sound of physical vibration, the sound of physical vibration, which firstly reach the audience’s auditory system.
And the second layer is the amplifying physical sound by the use of a contact microphone.
Then the third layer will be the echo produced after the usage of the sound processor.
After this process, the sound itself forms a three-layer space: Physical space, Digital space and the Virtual Echo space. Meanwhile, the echo message will form a virtual reality in a human’s brain.
If we say that the origin of Sound Art comes from the virtual reality, hence as the sound message reach the human auditory system after digital processing, will it be another “virtual reality”?
The virtual reality of sound varies as technology developed. Therefore, the Sound Ontology issue would be changing as well.