Question: Sun Wei  involves the field recording of which component of the acoustic environment that can be perceived by humans?

<P0-S0> Sun Wei (; born 11 September 1976 in Beijing, China) is a sound artist who uses sound and installations as sampling carriers. <P0-S1>  He has been featured and performed in experimental events in China. <P0-S2>  Its creation involves the field recording of environmental soundscapes, live performances, and environmental sound installations. <SEP> <P1-S0>  There is a varied history of the use of soundscape depending on discipline – ranging from urban design to wildlife ecology. <P1-S1>  An important distinction is to separate soundscape from the broader term acoustic environment. <P1-S2>  The acoustic environment is the combination of all the acoustic resources within a given area – natural sounds and human-caused sounds – as modified by the environment. <P1-S3>  The International Organization for Standardization (ISO) standardized these definitions in 2014. <P1-S4> (ISO 12913-1:2014) <P1-S5> The soundscape is the component of the acoustic environment that can be perceived by humans. <SEP> <P2-S0> The Battle of Guìlíng (桂陵之戰) was fought between the states of Qí and Wei in the Warring States period of Chinese history. <P2-S1>  In 354 BC, an army from Wèi was laying siege to Handan, the capital of the State of Zhao. <P2-S2>  The next year, Zhao turned to Qi for help. <P2-S3>  Tian Ji and Sun Bin, acting as co-commanders of Qi, led an army to save Zhao. <P2-S4>  Sun Bin moves south intentionally to make an unsuccessful attack on Pingling, intending to convince Pang Juan that the Qi Army was too weak to achieve victory. <P2-S5>  Pang Juan, falling for the ruse, pooled more of his forces to besiege Handan. <P2-S6>  Although defeated, the Zhao Army fought desperately and suffered heavy losses to the Wei Army in the subsequent battle. <P2-S7>  After feigning defeat at Pingling, Sun Bin led his army directly to the Wei capital, Daliang. <P2-S8>  Wei scouts reported that the Qi Army had committed small groups to attack the city. <P2-S9>  Upon hearing the report, Wei general Pang Juan took his crack cavalry and left his infantry and supplies at Handan, making a mad dash in an attempt rescue Daliang. <P2-S10>  Pang Juan's troops were exhausted as they crossed the Yellow River and were ambushed and destroyed at Guiling by Sun's numerically superior army. <P2-S11>  Pang Juan managed to escape alone to Wei. <SEP> <P3-S0> Direct-field acoustic testing, or DFAT, is a technique used for acoustic testing of aerospace structures by subjecting them to sound waves created by an array of acoustic drivers. <P3-S1>  The method uses electro-dynamic acoustic speakers, arranged around the test article to provide a uniform, well-controlled, direct sound field at the surface of the unit under test. <P3-S2>  The system employs high capability acoustic drivers, powerful audio amplifiers, a narrow-band multiple-input-multiple-output (MIMO) controller and precision laboratory microphones to produce an acoustic environment that can simulate a helicopter, aircraft, jet engine or launch vehicle sound pressure field. <P3-S3>  A high level system is capable of overall sound pressure levels in the 125–147 dB for more than one minute over a frequency range from 25 Hz to 10 kHz.