ALESIS ANDROMEDA A6 User Manual

Page 126

Chapter 5: Oscillators and Filters

124

NDROMEDA

A6 R

EFERENCE

ANUAL

4. The composite output of the

PRE FILTER MIX

, the Band Pass output of

FILTER 1

or the Notch output of the of the

POST FILTER MIX

can be selected as the input

FILTER 2

for additional 4-pole low pass filtering.

The

F2 INPUT

button is used to route these signals into

FILTER 2

. Pressing this

button repeatedly switches between

MIX

NOTCH

BP,

or nothing as the input to

FILTER 2

•

When

MIX

is selected, the source of

FILTER 2

is the

PRE FILTER MIX

—the

oscillators, ring mod and Noise. This is the same signal that goes to

FILTER 1

So when

MIX

is used, you have both a 2-pole multi-mode filter (

FILTER 1

) and

a 4-pole low-pass filter (

FILTER 2

) operating in parallel.

This provides unprecedented capabilities in analog filtering. You now have
the ability to route the same signal to two independent VCFs – with identical

or different modulations.

•

When

NOTCH

is selected, two things happen:

•

the source of

FILTER 2

is only the notch-filtered output of

FILTER 1

(which

is the post-fader sum of Filter 1's low-pass and high-pass sections)

•

and those two volume controls of Filter 1 are disconnected from a direct

connection to the VCA.

In other words, when

NOTCH

is used, you have two parts of a multi-mode

filter (

FILTER 1

) and a 4-pole low-pass filter (

FILTER 2

) connected in series.

Note that you won't hear any output from

FILTER 2

unless either or both of

Filter 1's

HIGH PASS

LOW PASS

knobs are up. Only the

BAND PASS

knob will

send audio from Filter 1 directly to the VCA on its own.

In this case "notch" is a relative term, assuming that both the knobs are up. If
the

HIGH PASS

knob is turned fully counter-clockwise, the notch effect is

defeated and the low-pass output of

FILTER 1

is left as the signal. By the same

token, if the

LOW PASS

knob is turned fully counter-clockwise instead, the

notch effect is also defeated but the high-pass output of

FILTER 1

remains.

So, in essence, the

NOTCH

function can also be considered a low-pass or high-

pass input from

FILTER 1

, depending on how the

LOW PASS

HIGH PASS

knobs are set.

•

When

is selected, only the band-pass output of

FILTER 1

is input to

FILTER

. Unlike NOTCH mode, however, the

FILTER 1 BAND PASS

volume control