Yamaha SY99 Owner's Manual page 162

set for the same parameter of the other filter.
This is useful when you are using the two filters
in tandem to act as a steep 24 dB/octave filter or
as a 12 dB/octave band pass filter. See the
following explanation Type and Cutoff Freq.
Press F6 once again to cancel filter sync editing
mode.
Type and Cutoff Freq: Filter 1 can be used either
as a Low Pass Filter (LPF) or as a High Pass
Filter (HPF), and filter 2 can be used only as a
LPF.
When set to LPF, filters 1 and 2 will allow
sound lower than the cutoff frequency to pass
unchanged, and will diminish the sound above
the cutoff frequency. When set to HPF, filter 1
will allow sound higher than the cutoff frequency
to pass, and will diminish the sound below the
cutoff frequency.
By setting filter 1 to HPF and filter 2 to LPF,
you can create a Band Pass Filter that passes
only a central band of frequencies.
Each of the SY99's filters has a slope of
12 dB/octave. This means that if the cutoff
frequency of an LPF is 1 kHz, frequencies at
2 kHz will be reduced by 12 dB and frequencies
at 4 kHz will be reduced by 24 dB. If you set
both filters 1 and 2 to LPF, set both to the same
cutoff frequency, and set both filter EGs in, the
same way, the result will be the equivalent of a
single 24 dB/octave filter. The filter copy function
explained in 8.0 Copy filter is a quick way to give
both filters the same settings.
24 dB/octave filtering creates a sharp cutoff
which is quite obvious, while 12 dB/octave filter-
ing is a more subtle effect. Analog synthesizers
of the past have used both types. 12 dB/octave
filtering was considered especially suitable for
strings, and 24 dB/octave filtering was com-
monly used for brass or synth bass sounds.
Resonance: Resonance lowers the level of sound
below the cutoff frequency, creating an increased
peak of emphasis. (This may reduce the overall
volume.) High settings of resonance will make
changes in cutoff frequency quite easy to notice.
When the two filters are being used in tandem
as a Band Pass Filter (i.e., when filter 1 is set to
HPF), resonance will have no effect.
Extremely high settings of filter resonance will
make the filter oscillate so that it produces a
pitch of its own. This is a technique often used
on analog synthesizers of the past.
Ctrl = LFO: When Ctrl is set to LFO, the filter will
be controlled both by the Main LFO and by the
controller which has been assigned to Filter
Cutoff Depth. (Refer to Voice common data
12. (F4) Controller set (Pan), page 130.) Key
velocity will shift the cutoff frequency.
VOICE EDIT MODE
151