Octave Analysis - Adash VA4 Pro II User Manual

ADASH

Octave Analysis

Using of this mode is similar to Analyzer mode. You need to create Set and Measurements like in Analyzer.
Measurement parameters are:
Type octave spectrum
sound level
equivalent sound level
equivalent sound level is the average sound level of the whole interval.
Channel
Unit the unit of measurement ( has to be compatible with sensor settings)
Resolution
Frequency Range
Frequency Weighting
The human ear has the subjective characteristics known as the loudness. It is the function of sound intensity
and frequency. For example the 20Hz pure tone with sound level 20dB would be clearly audible. The 100Hz
with the same level would not be heard, it lies below the threshold of hearing. The unit of loudness is phon. The
loudness level in phons of any sound is defined as being numerically equal to the intensity level in dB of a
1000Hz tone. The purpose of weighting is to make the readings correspond as closely as possible to the
loudness level. Historically four weighting were defined:
A used for loudness levels below 55 phons.
B used for loudness levels between 55 and 85 phons.
C used for loudness levels over 85 phons.
D used especially for aircraft noise.
However today is A-weighting frequently specified for measurements irrespective of level.
Averaging linear
peak hold
exponential
Avg number of averages
For further technical and contact information visit
the sound pressure level in dB is defined as 20log
p =0,00002 Pa ( p is sound pressure)
0
1 - 4
1/1, 1/3, 1/12, 1/24
high 16 - 16000 Hz for noise measurements (central octave frequencies)
low 1 - 1000 Hz for vibrations
none, A, B, C, D
the standard arithmetic mean for every line
the maximum value during the measurement for every line
the continuous measurement where the older spectra have less weighting then
the newer
when during time interval the sound level changes, then the
122
www.adash.com
Adash 4400 – VA4Pro
(p /p
10 RMS
or email: info@adash.com
),
0