User Manual

SPECTRALIS 2

4/27:VCO Multimode Filter Volume

Osc1:00 Osc2:00 Osc3:00 Osc4:00

As suspected all of them are set to 0!! No wonder there was no audible signal

from the multimode-filter. We definitely need to up the oscillator-level for the

multimode-filter. You can generously set all levels to a value of 230 and then

turn the (CutOff MM)-encoder again. Depending how high the cutoff-frequency

of the lowpass was set, you should now definitely hear a sonic change. However

if the 24dB filter is completely closed, you won’t be hearing any signal from

the multimode filter either anymore. Go ahead and open the (CutOff-LP)-

encoder some more, so that the multimode filter can be heard clearly. Increasing

the resonance of the multimode-filter even more (RESO MM), makes the

highpass filter effect even more apparent.

Still, you will only hear the signal if the 24dB lowpass is open as well. You can easily

find out why this is the case by looking at the current routing. At this time all four

oscillators are being routed both to the 24dB lowpass-filter and the multimode-filter.

While the output of the lowpass filter is connected with the output of the Spectralis,

this doesn’t appear to be the case with multimode filter. Otherwise we’d obviously

be hearing the ighpass-effect even when the lowpass is closed. The multimode-filter

is only sending its signal to the 24dB lowpass filter. To clarify this even more, we

have created a diagram, which is intended to illustrate the signal-flow for the selected

sound:

We hope that the drawing is somewhat helpful to you, rather than confusing you even

more. In the diagram you can see the individual modules. To make things a little

simpler we did leave oscillators 3 and 4 off. We also didn’t include any non-relevant

part of the routing. The sum-bus for instance is shown in Mono mode, while the

original is actually in stereo. It is of no particular consequence though for now. It’s

basically a simplified diagram of the routing.

All Encoders shown in grey are open. All the ones shown in white are set to 0. As

you can see in the drawing the signal is being sent by all oscillators both to the

multimode filter as well as to the 24dB lowpass filter (keeping in mind that

you have just opened the levels to the multimode-filter yourself).

You can also see, that only the 24dB lowpass filter is connected with the sum-

Hybrid engine - Multimode-filter and filter-routing