little confused about filter modulation

Tips and techniques for Minimoog Analog Synthesizers
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n2design
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little confused about filter modulation

Post by n2design » Tue Jan 01, 2013 12:24 am

Hi All,
Ive been playing with the CP-251 to perform filter sweeps, but it only seems to affect a particular bandwidth depending on where the filter knob is currently positioned.

So for example, if I have the filter set to the [1k]. My sweep seems to span [250, 2k ] rather than the entire spectrum [20, 12k]

I'm guessing that I'm doing something wrong here, anyone got any tips ?

In case this might matter, I am trying to use the super long lfo described on knob tweak.


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stiiiiiiive
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Re: little confused about filter modulation

Post by stiiiiiiive » Tue Jan 01, 2013 9:36 am

Well, I guess it's normal: voltages from the knob and the CV input are added, anyone correct me.
I would say you should check the filter cutoff voltage range and attenuate/amplify/offset what comes from the CP.

Hope this helps :)

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misterpete
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Re: little confused about filter modulation

Post by misterpete » Tue Jan 01, 2013 4:17 pm

The CV range is set at the knob, before you add or take a way voltage. So if you are going in one direction your sweep will begin at the setting you start from ~ there are reminders and examples of this for specific parameters in the docs. You can also control the top limit by attenuating down on an attenuator or rolling back the knob on an EP-2 pedal.

For a dial with a range from - 5 to + 5 if you set it in the middle at zero in between the two extremes - like Voyager PAN or the FEEDBACK on a ClusterFlux 108 you can send CVs in both directions sending "-" or "+"

You can't send "-" CV from an EP-2 - but a CP-251 will do it easily and/or the front panel of an XL has several options as well

n2design wrote:Hi All,
Ive been playing with the CP-251 to perform filter sweeps, but it only seems to affect a particular bandwidth depending on where the filter knob is currently positioned.

So for example, if I have the filter set to the [1k]. My sweep seems to span [250, 2k ] rather than the entire spectrum [20, 12k]

I'm guessing that I'm doing something wrong here, anyone got any tips ?

In case this might matter, I am trying to use the super long lfo described on knob tweak.


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EricK
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Re: little confused about filter modulation

Post by EricK » Tue Jan 01, 2013 4:58 pm

I generally position the filter cutoff frequency in the middle of the range I want the cv to sweep and attenuate the voltage down from there.
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n2design
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Joined: Sun Feb 12, 2012 3:38 am

Re: little confused about filter modulation

Post by n2design » Tue Jan 01, 2013 5:40 pm

Doesn't sound like there is enough voltage to sweep the entire spectrum. Looks like I will have to use midi for those times when I want a open spectrum.

Thanks all for the tips!

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stiiiiiiive
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Re: little confused about filter modulation

Post by stiiiiiiive » Tue Jan 01, 2013 8:44 pm

You could route the LFO to two mixer inputs one of which has an attenuator. Start whit the later fully attenuated, and bring it back little by little untill there is enough voltage for the desired modulation.

This should work, shouldn't it?

vasago
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Re: little confused about filter modulation

Post by vasago » Tue Jan 15, 2013 5:19 pm

couldnt this be easily remedied by the amount knob of an LFO on the voyager itself? Unless I am totally missing the point...
Voyager Performer FR Revox2 Taurus3 mf;102,103,104zx2,105m,CP251x1 SEM Xpander 808 606 pro1x2 FR XS, FRorbx3 Modfactor timefactor space mopho PolyE Nord g1 Vermona drm mk3 KP3x2

n2design
Posts: 150
Joined: Sun Feb 12, 2012 3:38 am

Re: little confused about filter modulation

Post by n2design » Tue Jan 15, 2013 5:45 pm

vasago wrote:couldnt this be easily remedied by the amount knob of an LFO on the voyager itself? Unless I am totally missing the point...


LFO amount knob? That's actually LFO rate knob.

vasago
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Re: little confused about filter modulation

Post by vasago » Tue Jan 15, 2013 6:33 pm

No the amount knob at the bottom of each mod/buffeR? that sets the amount of modulation for each? The LFO rate knob is on the far left...
Voyager Performer FR Revox2 Taurus3 mf;102,103,104zx2,105m,CP251x1 SEM Xpander 808 606 pro1x2 FR XS, FRorbx3 Modfactor timefactor space mopho PolyE Nord g1 Vermona drm mk3 KP3x2

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