Using A Notch Filter; Bandpass Vs. Using The High Pass Filter 1 And Low Pass Filter 2 In Series; About The Bandpass Invert Button; Getting The Filter To Scream - Alesis Andromeda A6 Tips And Tricks Manual

Well little did I know, you can use the 12db filter to add warm overdrive to the signal path :) If you
set the filter cutoff of Filter 1 to 22khtz and crank the Resonance up you get a nice warm overdrive.
even at 100 your not gonna hear it much at that freq, especially since the 24db Filter will be filtering
out those frequencies. What you will hear is the valve like subtle overdrive! YUM!
If you like the Minimoog, this will do wonders in making A6 sound like that :) Add a nice growl to the
sound.
Actually sound more like analog tape saturation :)
Also you can try this with the 12db HPF instead pull the cutoff down to the minimum and add 80
resonance This boost the subsonic-frequencies and overdrives them adding new harmonics much
like what transformers in my valve gear do - bit like what those bass enhancers do actually :)
Another thing to try - use both the 12db LFP and HPF at the same time! Put the 12db filter cutoff at
22khtz or right at the bottom. I don't know why, but I can hear a tonal change.

3.16 using a notch filter:

The Andromeda does not explicitly have a volume for " notch filters" . However, it does have
this capability. Simply mix the High Pass Filter and Low Pass Filter (from filter 1) in the mix
level. The " bandpass invert" function is not a band reject filter, its function is described
below.
3.17 bandpass vs. using the high pass filter 1 and low pass filter 2 in
series:
The two WILL sound different. Briefly: You can use the " notch" setting, and turn the high
pass filter all the way up (and low pass all the way down), to set up this type of setting. This
is in effect a bandpass filter, but with different slopes. It could be nice for a subtle, different
effect.
From Colin:
In terms of where the filtering starts and stops (the width of the BPF), it should be 3dB down
outside a fairly tight peak which would get tighter with increasing resonance. MC will know how
wide that is in a SV filter.
Ok thanks - I keep thinking all this time it was -12db on either side of the cutoff point with a small
gap between with no filtering. So that's why running the 12db HPF and the 24 LPF in series with a
gap between em to create a bandpass sounds so different.

3.18 about the bandpass invert button:

Mike Peake wrote:
The Bandpass Invert button only inverts the phase of the BP output, it doesn't turn it into a BR filter
type. The Notch (mixing HP+LP) is a BR. You may only hear the change of inverting the BP when
it's mixed with other Filter outputs, where it can be used to do some broad phase cancellation. Or
not, with increasing resonance.

3.19 getting the filter to scream:

Colin found that filter feedback is the key to emulate a screaming type of filter sound, what
he thought was similar to his AX-73. Using a negative sawtooth waveform, and filter 2 (the
Moog filter), he was able to get a really nasty dirty sound, with larger VCOs. A very neat
trick for roughness.