The noise ordinances do not specifically enumerate decibel levels, but here are the sections of the municipal ordinances dealing with noise and describing what violates the code:
9.44.010 Noises—Prohibited when loud, disturbing.
No person shall make, continue or cause to be made or continued, within the limits of the city, any loud, disturbing, or unusual noise which injures or endangers the health, peace or safety of persons of reasonable sensibilities: provided, that this section shall not in any way affect, restrict or prohibit any activities incidental to scientific or industrial research or manufacturing, construction or repairing conducted in areas zoned for such purposes.
The following acts, among others, are determined to be loud, disturbing and unusual noises, although such enumeration shall not be deemed to be exclusive:
A. The use or operation of any radio, receiving set, musical instrument, phonograph, loudspeaker, sound amplifier, or any other machine or device producing or reproducing sound which is cast upon the streets for the purpose of commercial advertising or attracting the attention of the public to any building or structure;
B. The keeping of any animal in violation of Section 6.04.125 of this code;
C. The shouting and crying of peddlers, hawkers and vendors which disturbs the peace and quiet of the neighborhood;
D. The using, operating or permitting to be used or operated, any radio, musical instrument, phonograph, or any other machine or device for the reproducing of sound in such a manner as to disturb the peace, quiet or comfort of the neighboring inhabitants or business establishments by any restaurant, drive-in or other commercial establishment.
9.44.020 Enumeration of disturbing noises.
No person shall use, operate, or permit to be used or operated any device, horn or musical instrument, bell, or mechanical production or reproduction of sound by vehicles or aircraft so as to emit or transmit any loud and raucous noise within the city.
As defined by this section, “loud and raucous noise” means any of the following:
A. Any noise made by the motor of any automobile, truck , tractor, motorcycle, or aircraft of any kind not reasonably required in the operation thereof under the circumstances, and shall include but not be limited to backfiring, motor racing, and the buzzing by airplanes;
B. The sound of the discharge of any gun or other explosive, except by or with the permission of the governing body having control of the highway or thoroughfare;
C. The human voice or any record or recording thereof when amplified by any device, whether electrical or mechanical or otherwise; or any sound not included in the foregoing which is of such volume, intensity, or carrying power as to tend to interfere with the peace and quiet of persons upon public or private property or other users of the public highways and thoroughfares.
9.40.010 Disturbing the peace.
No person shall maliciously and willfully disturb another person by loud and unreasonable noise, or use offensive words which are inherently likely to produce a violent reaction, or unlawfully fight or challenge another person to fight on any street, alley, sidewalk, square, park, or in any store or other public place in the city.
Hope this helps.