| Sound Pressure Levels (SPL) "Hey Mr. DJ!
It's too loud, we can't talk"!
That is a confusing comment to a DJ. Most DJs are hired to fill the dance floor, not
provide talking music. And loud music drives the dance floor. However, the real
problem with loud music is not conversation verses driving the dance floor, it is NIHL
(Noise-induced Hearing Loss). Loud noise studies have found that sounds of
sufficient intensity and duration will damage the ear and result in temporary or permanent
hearing loss. The hearing loss may range from mild to profound and may also result in
tinnitus (ringing in the ear). The effect of repeated sound over stimulation is cumulative
over a lifetime and is not currently treatable.
What sounds can damage hearing?
Damaging sounds are those that are sufficiently strong, sufficiently long lasting, and
involve appropriate frequencies so that permanent hearing loss will ensue.
Most of the sounds in the environment that produce such permanent effects occur over a
very long time (for example, about 8 hours per workday over a period of 10 or more years).
On the other hand, there are some particularly abrupt or explosive sounds that can cause
damage even with a single exposure. It is important to note that the line between these
categories of sounds cannot be stated simply because not everybody responds to sound the
same way. Thus, it is difficult to specify a sound of given frequency bandwidth, level,
and duration that will be considered hazardous to everyone and what type of damage it will
cause (whether anatomical, audio metric, speech understanding, etc.).
For simplicity sake, OSHA has established standards based on the length of the exposure to
the sound's strength or amplitude is called sound pressure level (abbreviated SPL) which
is measured by a sound-level meter in units called "decibels" (dB) in relation
to the length of time of the exposure. An example of decibels (dB) measurement would be
the sound level of speech at typical conversational distances is between 65 and 70 dB
verses a typical Gun Shot is 140 dB. |
