about the noise and amplified sounds prevention risks was published in the 9 August '17 French Official Journal.
This decree is also very clearly related to movie theaters and defines the values not to be exceeded:
"1° Never exceed, at any time and in any place accessible to the audience, continuous sound pressure levels equivalent to 102 A-weighted decibels over 15 minutes and 118 C-weighted decibels over 15 minutes.
Where these activities involving the amplified sounds broadcast are specifically intended for children up to the age of six, these sound pressure levels shall not exceed 94 A-weighted decibels over 15 minutes and 104 C-weighted decibels over 15 minutes;
In A-weighting, for a level under 60 dB, low and high frequencies are drastically dimmed compare to medium frequencies.
dB(A) is the unit closest to the feeling perceived by the human ear at low or medium level.
In C-weighting, for a level greater than 80 dB, the curve is almost straight.
The dB(C), which does not balance the low frequencies, is used to measure the annoying noise, because bass sounds propagate better than high-pitched sounds and can therefore easily inconvenience the neighbourhood.
CST #166 Letter
publishes an article entitled: Sound reproduction: appreciate and understand
, as well as a presentation by Dr. Meyer-Bish ENT at Beaujon Hospital on the mechanism of the human ear and about the consequences of what we are doing to it. Audio recordings of presentations and lectures on this topic are available on the CST website.
It should be quoted that the CST has long advocated a limitation in movie theaters at 85 dB(C) per channel or 105 dB(C) overall.