Voyager Filter Spacing double LP mode

The Moog Forum Minimoog Forum
1

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?

2

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

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

https://forum.moogmusic.com/viewtopic.php?f=2&t=3556&hilit=Spacing

3

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:

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 :slight_smile:

4

So the behavior of mine is as expected.
Thank you very much for the link!

5

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.

6

Now that’s precision!
Thanks :slight_smile:

7

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!

8

Now that is quite confusing! I’d never have expected this.

And this is exactly how mine works. Thank you for the clarification!

9

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?