558.01  DEFINITIONS.
   As used in this Chapter:
   (a)   "A-Weighted Sounded Level" means the sound pressure level in decibels as measured on a sound level meter using the A-Weighting network.  The level so read is designated dBA.
   (b)   “Cyclically Varying Noise" means any sound which varies in sound level that is obtained repetitively at reasonable uniform intervals of time.
   (c)   "Decibel" means a unit for measuring the volume of sound, equal to twenty (20) times the logarithm to the base ten (10) of the ratio of the pressure of the sound measured to the reference pressure, which is twenty (20) micronewtons per square meter.
   (d)   "Gross Vehicle Weight Rating" means the value specified by the manufacturer as the recommended maximum loaded weight of a single motor vehicle.  In cases where trailers and tractors are separable, the gross combination weight rating (GCWR), which is the value specified by the manufacturer as the maximum loaded weight of the combination vehicle, shall be used.
   (e)   "Impulsive Sound" means sound of short duration, usually less than one (1) second, with an abrupt onset and rapid decay.  Examples of sources of impulsive sound include explosions, drop forge impacts and the discharge of firearms.
   (f)   "Noise" means an unwanted sound, any sound not occurring in the natural environment, such as sounds emanating from aircraft, highways, industrial, commercial and residential sources, or an erratic, intermittent, or statistically random oscillation.
   (g)   "Noise Disturbance" means any sound which:  endangers or injures persons or property, the standard for which shall be as established in Sections 558.03 and 558.04 of this Chapter.
   (h)   "Plainly Audible" means any sound that can be detected by a person using his or her unaided hearing faculties.
   (i)   "Receiving Property" means any property which is affected by sound originating from another location.
   (j)   "Repetitive Impulsive Noise" means any noise which is composed of impulsive noises repeated at sufficiently slow rates so as to cause a sound level meter set at "fast" meter characteristic to show changes in sound.
   (k)   "Sound" means an oscillation in pressure, particle displacement, particle velocity, or other physical parameter, in a medium with internal or interval forces that cause compression and rarefaction on that medium, and which propagates at finite speed to distant points.  The description of sound may include any characteristic of such sound, including duration, intensity and frequency.
       (l)   "Sound Level" means the weighted sound pressure level obtained by the use of a sound level meter and frequency weighting network, such as A, B, or C as specified in American National Standards Institute specifications for sound level meter Publication S1.4-1971, or the latest approved revision thereof.  If the frequency weighting employed is not indicated, the A-Weighting shall apply.
   (m)   "Sound Level Meter" means an instrument, including a microphone, amplifier, RMS detector and integrator, time averager, output meter and/or visual display and weighting networks, that is sensitive to pressure fluctuations.  The instrument reads sound pressure level when properly calibrated and is of Type Two (2) or better as specified in American National Standards Institute Publication S1.4-1971 or the latest approved revision thereof.
   (n)   "Sound Pressure" means the instantaneous difference between the actual pressure and the average or barometric pressure at a given point in space, as produced by sound energy.
   (o)   "Sound Pressure Level" means twenty (20) times the logarithm of twenty (20) micropascals (20 x 10 - 6 N/m2).  The sound pressure level is denoted Lp or SPL and is expressed in decibels.  (Ord. 112-01.  Passed 9-24-01.)