IVIE IE-10A, Owner'S And Operator'S Manual

Page: 30 / 88

To use the c h a r t , r s t measure t h e
l e v e l s o f t h e two sources independentl
y
and then f i n d t h e d i f f e r e n c e between
the two l e v e l s . L o c a t e the d i f f e r e n c e
on the bottom o f t h e c h a r t .
Go up
u n t i l the c u r v e i s i n t e r s e c t e d , and
then go l e f t t o t h e v e r t i c a l a x i s .
Then add t h e c o r r e c t i o n i n dB i n d i c a t e d
by the v e r t i c a l a x i s t o t h e v a l u e of
t h e h i g h e s t r e a d i n g made.
T h i s
number i n d i c a t e s t h e combined SPL of
the two sources.
Example: Source 1
=
79
dB
Source 2
=
69 dB
D i f f e r e n c e
=
10 dB
C h a r t c o r r e c t i o n
=
dB
T o t a l n o i s e
=
79.5 dB
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