Bandpass:
A Bandpass filter is a combination of Highpass and Lowpass. Extremely high and extremely
low frequencies are filtered. A specific (usually narrow) frequency band is allowed through.
You can further change the sound by using different filter types on specific frequencies.
There are more filter types, but the ones we just mentioned are the most effective ones for
musical purposes. That’s why we’ve included these in the Sunsyn.
The most important Parameters are:
Cutoff-Frequency:
This frequency determines the point where the filter starts working. Frequencies above the
cutoff frequency (Lowpass) or frequencies below the cutoff frequency (Highpass) are filtered
out of the signal. You can set the cutoff frequency with the Cutoff knob.
This means that the cutoff parameter has a different effect for Lowpass or Highpass. When
used in Lowpass mode, the cutoff frequency is
moved to the right (graphically) when opening the
filter and turning the knob to the right. Only very
high frequencies are removed from the signal. The
audible signal range remains almost unchanged. If
it seems as if the filter doesn’t work, switch the
filter type to Highpass. This means that all
frequencies to the left of the cutoff frequency are
removed from the signal. If the filter doesn’t seem
to affect the signal in Lowpass mode, then it’ll have maximum effect when using that cutoff
setting in Highpass mode. Conclusion: Lowpass and Highpass mirror eachother to a certain
extent.
Accordingly, the effect of the cutoff parameter reverses depending on the filter mode;
Lowpass or Highpass.
Filter Poles:
The amount of filter poles defines how steep the filter curve is. It defines how much the
selected frequencies will be faded out of the signal. A certain physical law defines that a pole
corresponds to a weakening of the
frequencies at 6db per octave. If you
want a stronger filter that works more
effectively, then you need to cascade
several filter poles. For musical reasons,
a combination of up to four filter poles
has become the most common filter
structure.
VCF Filter
3-6
032
Single Mode
Frequenzy
Level
1.Pole
2.Pole
3.Pole
4.Pole
Frequenzy
Cutoff
Frequenzy
Level
Low Pass
High Pass
Band Pass
Cutoff
Frequenzy
Cutoff
Frequenzy
Cutoff
Frequenzy
Level
Frequenzy
Frequenzy
Level
Level
Frequenzy
thebook-all 07.11.2002 18:28 Uhr Seite 32 (Schwarz Bogen)
