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Noise Dose Meters
Here you will find industrial
standard noise
dose meters. With these portable noise
dose meters
you can carry out measurements quickly to gain control of a
situation or to set the devices to take timed measurements. The
measurement of sounds has importance in all industries,
especially by way of a mobile device which is able to assess office
stress levels or street noise levels. Often problems arise from
noisy neighbours or if bars and restaurants are in residential areas
produce noise levels after 10pm in excess of what local laws
permit. We, of course, can assess which noise analyser you require
in relation to the issue you have and the relating laws. We also
have microphone extension cords (except for the PCE-999), tripods,
calibrators and calibration certificates for all models. If you
don't find the noise dose meters you are looking for, please contact
us and we will help you find the best solution to suit your needs by
calling our offices on:
+44 ( 0 ) 191 377
3398
and our technical staff will advise you
regarding our
measuring instruments.
At the following links you will find
technical specifications for all our Noise dose meters: |
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A-weighting
The sensitivity of human hearing
depends on the frequency. Low and high tones are perceived with less
precision than the tones in between. In the measurement of noise or
sound this is taken into account and the frequencies contained
within the sound are valued differently with respect to the A-weighting
curve.
Sound
readings are taken in decibels (dB) (A). The A-weighting curve is
used primarily in the environmental and industrial sectors; the B
and C curves are used for louder sounds and are less frequently
used. The noise dose meters most commonly used for these measurements are the
PCE-999
and the
PCE-322A.
Measurement level
The
measured sound level calculated over a period of time in a
measurement of noise which has certain noise level specifications be
means of noise level corrections. For these measurements it is
advised to use noise dose meters with the
Frequency
analysis
function.
Abbreviatons: RL (rating level),
during daytime (LT); during nightime (LN) (in dB).
In American
English it is also referred to as Ldn frequency.
Decibel
The decibel
consists of one tenth of a bel (B). A bel is defined as a logarithm
of the bahaviour of two readings of the same type. It is used for the measurement of sound levels although the actual
sound output is determined in relation to a specified reference
intensity
Abbreviation: dB.
Calculation: LP = 10 * log (P / P0)
in dB
where
P = sound output
P0 = specified reference
intensity (typically, 10 - 12 Watt)
Equivalent continuous noise level
(Leq)
The equivalent
continuous noise level is an energy mean of the noise level averaged
over the measurement period (T) and often regarded as an average
level.
Its also part of a sound level over a duration of time (X)
that describes a noise with duration D has the same value as a noise
that has half the duration (D / 2), but for this it has a sound
level of 3dB ( = 10 * log 2) higher
(to take this measurement you require the
Sl-1353
noise analyser.)
The Leq is calculated in this way:
Leq = q/log2 * log(1/T ( 10(log2/q)* Li * ti)
Li = unique event level
T = period of measurement (for
example: 16 hours),
ti = duration of the unique event, the
maximum level can't be increased by more than 10dB,
q =
equivalence parameter or division by two. Provides the change of
level, that is equivalent to a constant level to duplicate or divide
by two the effective time. Normally at international level q=3,
corresponding to the energy equivalence.
Regular measurment
of chance occurances with constant intervals
(example, 1/10 or 1/100 s) the value can be occur analogically
to the number of the chance value
Leq = q/log2 * log(1/N ( 10 (log 2/q)* Li)
where
Li = value of chance occurance
N = total number of
chance occurances over a period of measurment.
The sound level of
extended duration with equivalent energy used for acoustic
description of different sources of environmental noise (noise
from planes, trains, etc.) In Germany the Leq is normally know as the level
median (Lm).
Infrasound
Frequencies
below 16 Hz (Hz = 1/s)
Solid bodies
Sound that
spreads and impacts with solid bodies such as ceilings and walls of
buildings. This has high importance in the noise produced by the
construction sector.
Level day-evening-night
(Lden)
According to the
proposed directives of the EU relating to "Measurement and treatment
of environmental noise" for the index of produced noise: day/evening/night
level. The evening hours are 19:00 to 23:00
o'clock, with a supplement of 5dB and at night from 23:00 to 7:00
o'clock, with a supplement of 10dB (for example, the noise analyser
serie-1900.)
Ldn
Day-night average sound level is the average noise level over a 24
hour period. With it, different measurements can be taken at
different times of the day.
Maximum level
Maximum value is a sound event also denoted as a peak sound. In
sound bursts, it's easier todetermine various peak pints and
establish a maximum average or extract the L1 percentile level.
Sound pressure level
The magnitude of sound pressure of a source (px) relative to a level
reference sound pressure (p0). L = 20 log (px/p0). It is expressed
in decibels (dB), almost always compared with frequency value, for
example, dB (A).
Sound energy
The physical energy of a source of radiated sound.
Sound event level (SEL)
(also LAE). Parameter largely related to the LAeq. With it isolated
events can be determined
(for example, air transit or passing traffic). The sound
energy is normalized to a temporary duration of 1 second.
Peak level
Maximum sound
level reached in a sound burst, also called maximum level. Because
of possible loud oscillations, it provides a better description of
the average maximum level or the L1 percentile level.
Ruido TA
Technical
indication for the protection against noise
General prescription
administered by the Federal emissions law 26.8.98. In ruido TA value
directives are determined that should be followed precisely to
protect the public from the harmful effects of noise. Ruido TA has
advanced in force to be used for installations with authorization
and for those that don't require authorization.
Temporary value
To be
able to follow oscillating sound levels in display instruments that
were previously constant, different temporary constants are
introduced: Fast, Slow, Impulse. Normally the temporary value that
you should employ is prescribed.
Sound bursts are considered to
have a more imbalanced frequency than sounds events of longer
durations. For this reason, it has to be taken into account in the
reading, the duration of the bursts by way of a temporary value. (source: UBA). |
