E-MU 1212M PCIe - Manual (Page 90)

5 - Effects
Core Effects Descriptions
90 Creative Professional
However, when the Highpass Freq parameter is lower than the Lowpass Freq
parameter, the combined filter response is basically flat, since the passbands of each
filter combine to admit the entire spectrum. An exception occurs when there is
resonance added to the filters - you'll hear the resonant peaks as increased gain above
the otherwise flat spectral response.
Note that while the Highpass || Lowpass combination appears the same as the Band
Cut filter, this mode is different in several important respects:
• The rolloff points are independently adjustable as individual frequencies rather
than specified as a combination of center frequency and bandwidth.
• The rolloff slope of each High and Low filter can be specified separately while
each side of the Band Cut filter uses the same slope.
• The Resonance of each High and Low filter can be specified separately while the
Band Cut filter uses the same Resonance at high and low corner frequencies.
Band Pass
In this mode, the Lowpass and Highpass filters are connected in series to form a
bandpass filter, whose Center Freq and Bandwidth parameters are used to generate the
rolloff frequencies for the underlying Lowpass and Highpass filters. In this mode the
rolloff slope on the high and low sides of the passband is symmetrical and is limited to
a maximum of 24dB/octave. The Resonance is also common to both filter sections .
1
8d
B/
oct
24
d
B/oct
6d
B/oct
12
d
B/
oct
Resonance = 0
Band Cut
In this mode, the Lowpass and Highpass filters are connected in parallel to form a
band-cut filter, whose Center Freq and Bandwidth parameters are used to generate the
rolloff frequencies for the underlying Lowpass and Highpass filters. In this mode the
rolloff slope on the high and low sides of the cut-band is symmetrical and is limited to
a maximum of 24dB/octave.The Resonance is also common to both filter sections .
1
8d
B/oct
24
d
B/oct 6d
B/oct
12
d
B/oct
Resonance = 0