Voyager Filter Spacing double LP mode

Tips and techniques for Minimoog Analog Synthesizers
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oli@sub37
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Voyager Filter Spacing double LP mode

Post by oli@sub37 » Tue Mar 01, 2022 4:30 am

In LP/LP mode, equivalent negative and positive Filter Spacing values sound different. Fully positive sounds (right side) much brighter than fully negative (left side). Therefore, applying LFO modulation to Filter Spacing sounds asymmetric.

Is this normal?

Bass Player and Synthesist.
Voyager RME #1273 | Sub 37 #8490 with SSQ37 Update | Virus TI2 | Elektron MD MNM A4 | Roland SE-02 | Behringer Model D
Mac OS X 10.14 | Cubase Pro 11.0 | Ableton Live 9.6 | MainStage 3 | RME UFX+

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ummagumma
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Re: Voyager Filter Spacing double LP mode

Post by ummagumma » Tue Mar 01, 2022 7:08 pm

The spacing only adjusts the right filter cutoff in LP/LP

Take a look at Greg's explanation in post #2

viewtopic.php?f=2&t=3556&hilit=Spacing

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stiiiiiiive
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Re: Voyager Filter Spacing double LP mode

Post by stiiiiiiive » Wed Mar 02, 2022 9:21 am

Hmm it 's weird.

I've just had a look to the Voyager's manual and the schemes are misleading as they indicate that both filter frequencies move when SPACING is changed, each in its direction.

Moreover, the manual then states the following:
The Voyager's manual wrote:Setting the SPACING control to +1 in Dual Lowpass mode means that the right filter has a cutoff frequency equal to where the CUTOFF control knob is set, and the left frequency has a cutoff frequency that is one octave higher than the right filter.
Anyone having a Voyager, here is a simple way to check.
- Make sure the filters are configured in DUAL LP mode
- Keep only NOISE on in the mixer
- Set the VCA on drone mode
- Set CUTOFF frequency at a reasonable value and SPACING at 0
- Increase RESONANCE until you can clearly here a pitched sound.
- Now, increase slowly SPACING and listen: you can hear a second pitch sound going up. What about the first one: does it stay steady, or does it go down?
- If you find it difficult to listen to each peak separately, you can listen output at a time.

All that being said, I trust GregAE when he says he tested that :)

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oli@sub37
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Re: Voyager Filter Spacing double LP mode

Post by oli@sub37 » Wed Mar 02, 2022 5:03 pm

ummagumma wrote: Tue Mar 01, 2022 7:08 pm The spacing only adjusts the right filter cutoff in LP/LP

Take a look at Greg's explanation in post #2

viewtopic.php?f=2&t=3556&hilit=Spacing
So the behavior of mine is as expected.
Thank you very much for the link!

Bass Player and Synthesist.
Voyager RME #1273 | Sub 37 #8490 with SSQ37 Update | Virus TI2 | Elektron MD MNM A4 | Roland SE-02 | Behringer Model D
Mac OS X 10.14 | Cubase Pro 11.0 | Ableton Live 9.6 | MainStage 3 | RME UFX+

Markyboard
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Re: Voyager Filter Spacing double LP mode

Post by Markyboard » Thu Mar 03, 2022 12:39 pm

Yow - a lot of confusion and bad info here, but for a good reason.

This left/right channel nomenclature is not helping so lets start with...

Filter A: Right channel
Filter B: Left channel

This is per the user manual and matches the schematics. It assumes that your Voyager is wired correctly. I believe the headphone jack was originally mis-wired (reversed) on many Voyagers including mine. I've since corrected it to match the Main outputs. You can easily test this.

In LP/LP mode the spacing controls affects only Filter B which again is the LEFT CHANNEL.

If you're looking at the schematics don't let the fact that the spacing circuitry appears on the A filter schematic page . It's quickly feeds the developed bias voltage over to the B side schematic

Hope this helps.


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ummagumma
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Re: Voyager Filter Spacing double LP mode

Post by ummagumma » Fri Mar 04, 2022 1:59 am

Markyboard wrote: Thu Mar 03, 2022 12:39 pm Yow - a lot of confusion and bad info here, but for a good reason.

This left/right channel nomenclature is not helping so lets start with...

Filter A: Right channel
Filter B: Left channel

This is per the user manual and matches the schematics. It assumes that your Voyager is wired correctly. I believe the headphone jack was originally mis-wired (reversed) on many Voyagers including mine. I've since corrected it to match the Main outputs. You can easily test this.

In LP/LP mode the spacing controls affects only Filter B which again is the LEFT CHANNEL.

If you're looking at the schematics don't let the fact that the spacing circuitry appears on the A filter schematic page . It's quickly feeds the developed bias voltage over to the B side schematic

Hope this helps.
Haha, I was actually going to ping you about this!

I forgot about the headphone wiring: checked with cans on & erroneously deduced right instead of left. That's probably why everyone else is saying right too, I don't think it's common knowledge the headphones are reversed?

Thanks for clearing that up!

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oli@sub37
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Re: Voyager Filter Spacing double LP mode

Post by oli@sub37 » Sat Mar 05, 2022 7:26 am

Markyboard wrote: Thu Mar 03, 2022 12:39 pm This left/right channel nomenclature is not helping so lets start with...

Filter A: Right channel
Filter B: Left channel
Now that is quite confusing! I'd never have expected this.
Markyboard wrote: Thu Mar 03, 2022 12:39 pm In LP/LP mode the spacing controls affects only Filter B which again is the LEFT CHANNEL.
And this is exactly how mine works. Thank you for the clarification!

Bass Player and Synthesist.
Voyager RME #1273 | Sub 37 #8490 with SSQ37 Update | Virus TI2 | Elektron MD MNM A4 | Roland SE-02 | Behringer Model D
Mac OS X 10.14 | Cubase Pro 11.0 | Ableton Live 9.6 | MainStage 3 | RME UFX+

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ummagumma
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Re: Voyager Filter Spacing double LP mode

Post by ummagumma » Mon Mar 07, 2022 9:49 am

It makes sense, since the left channel is the mono out.

But from the front panel, adjusting the spacing knob "seems" right if it adjusts the right channel, through headphones. I wonder if that's how the headphone outs got flipped?

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