<P> Soundscape is the component of the acoustic environment that can be perceived by humans . The acoustic environment is the combination of all sounds (whether audible to humans or not) within a given area as modified by the environment and understood by people, in context of the surrounding environment . </P> <P> There are six experimentally separable ways in which sound waves are analysed . They are: pitch, duration, loudness, timbre, sonic texture and spatial location . </P> <P> Pitch is perceived as how "low" or "high" a sound is and represents the cyclic, repetitive nature of the vibrations that make up sound . For simple sounds, pitch relates to the frequency of the slowest vibration in the sound (called the fundamental harmonic). In the case of complex sounds, pitch perception can vary . Sometimes individuals identify different pitches for the same sound, based on their personal experience of particular sound patterns . Selection of a particular pitch is determined by pre-conscious examination of vibrations, including their frequencies and the balance between them . Specific attention is given to recognising potential harmonics . Every sound is placed on a pitch continuum from low to high . For example: white noise (random noise spread evenly across all frequencies) sounds higher in pitch than pink noise (random noise spread evenly across octaves) as white noise has more high frequency content . Figure 1 shows an example of pitch recognition . During the listening process, each sound is analysed for a repeating pattern (See Figure 1: orange arrows) and the results forwarded to the auditory cortex as a single pitch of a certain height (octave) and chroma (note name). </P> <P> Duration is perceived as how "long" or "short" a sound is and relates to onset and offset signals created by nerve responses to sounds . The duration of a sound usually lasts from the time the sound is first noticed until the sound is identified as having changed or ceased . Sometimes this is not directly related to the physical duration of a sound . For example; in a noisy environment, gapped sounds (sounds that stop and start) can sound as if they are continuous because the offset messages are missed owing to disruptions from noises in the same general bandwidth . This can be of great benefit in understanding distorted messages such as radio signals that suffer from interference, as (owing to this effect) the message is heard as if it was continuous . Figure 2 gives an example of duration identification . When a new sound is noticed (see Figure 2, Green arrows), a sound onset message is sent to the auditory cortex . When the repeating pattern is missed, a sound offset messages is sent . </P>

What is the measurement of low or high sound called