LxT Manual
Glossary and Formulas
C
-
27
:
Sound Pressure
The physical characteristic of sound that can be detected by
microphones. Not all pressure signals detected by a
microphone are sound (e.g., wind noise). It is the amplitude
of the oscillating sound pressure and is measured in Pascals
(Pa).
Sound Pressure Level (SPL,
L
p
)
The logarithmic form of sound pressure. It is also expressed
by attachment of the word decibel to the number. The
logarithm is taken of the ratio of the actual sound pressure to
a reference sound pressure which is 20 MicroPascals (
Pa).
There are various descriptors attached to this level
depending on how the actual sound pressure is processed:
Sound Power(W)
The sound power emitted by a sound source. It is measured
in Watts.
Sound Power Level (PWL,
L
w
)
The logarithmic form of sound power. It is also expressed by
attachment of the word decibel to the number. The logarithm
is taken of the ratio of the actual sound power to a reference
sound power, which is 1 pico-watt. Sound power level
cannot be measured directly, but can only be deduced
through measurements of sound intensity or sound pressure
around the source. The equation for it is
Sound Speed, (c)
The speed at which sound waves propagate. It is measured
in meters per second. It should not be confused with sound
or particle velocity which relates to the physical motion of
the medium itself.
N
L
n
/10
SEA
=
10 log
10
10
n = 0
L
w
10log
10
W
W
0
-------
=
W
W
0
10
L
w
10
=
c
49.03 degF 460
+
=
ft sec
Summary of Contents for SoundExpert LxT
Page 1: ...LxT Manual for SoundTrack LxT SoundExpert LxT TM...
Page 55: ...4 18 Measurement Settings Tabs LxT Manual...
Page 81: ...5 26 View Spectrum Normalized Optional LxT Manual...
Page 93: ...6 12 Data Storage After Improper Shutdown LxT Manual...
Page 110: ...LxT Manual Certification 7 17...
Page 143: ...11 6 Control Panel Data Explorer LxT Manual...
Page 167: ...12 24 Options LxT Manual...
Page 179: ...14 4 User LxT Manual FIGURE 14 5 shows the User tab FIGURE 14 5 User Tab...
Page 185: ...15 6 File System LxT Manual...
Page 191: ...16 6 Miscellaneous Parameters LxT Manual...
Page 206: ...LxT Manual Technical Specifications A 9 Typical Z Weight Frequency Response...