Klark Teknik HELIX SYSTEM DN9344 Operator's Manual page 55

Without changing modes or making any other selections, we can make the unit operate 'the other way up' just
by selecting suitable values for the two thresholds and levels see Figure 3.
igure 3 – Helix with boost at high signal level
+20
+10
+0
d
10
B
u
20
30
40
10
In this case, [low threshold] is -20dBu, [low level] is 0dB, [high threshold] is -5dBu, and [high level] is
+12dB, so that instead of cutting this frequency range as the level increases, we are now boosting it. Again,
we have precise control over the maximum amount of boost that will be applied, and the level at which this
will occur. Note the shape of the curve for -5dBu, which has 'expected values' outside the filter range and at
the centre frequency, but intermediate values that show the EQ ramping in and out either side of the centre
frequency.
Needless to say, there is no requirement for one of the levels to be 0dB. Figure 4 shows the transition from a
+12dB boost at low level to a -12dB cut at high levels. Again, the intermediate curves show the effect of the
sweep signal moving in and out of the 'area of interest'of the level detector as the curve is formed.
Helix with boost at low level and cut at high level
+15
+10
+5
+0
5
d 10
B
15
u
20
25
30
35
40
10
20 50 100
20 50 100
200 500 1k
Hz
200 500 1k
Hz
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l
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