i just discovered that when each of the osc is playing alone, it does not happen, but when 2 of them play together there is some frequency modulation goin on between them
it seems like i somehow changed by mistake the initial parameters setting so there is now some FM
how can i check it?
i listened very carefully now and i am almost sure that what i have here is an LFO modulation on the wave form, and like i said, in the initial parameters
where can it come from?
i checked in 5.4 pot mapping, and they are all in Amount-off, from which i understand that they are not active (?)
and still the modulation is very clear
???
Are you talking about phase cancellation?
I mean, like if both oscs are set to zero (on the display, not the panel) they will sound pretty much in sync with eachother. If you have different waveshapes, they will compete with eachother. It is an effect just like when an Osc is slightly detuned, you hear the beat frequency. I believe that this effect is called Phase Cancellation. It is like a chorus effect (could be mistaken for an LFO modulation) when you have more than on osc playing. I believe that this is caused by the cycling of the waveshapes themselves, not an actual modulation. If this is what you are hearing then this is a characteristic of analogue synthesizers and the nature of dualing oscillators.
Edit:
If what I am thinking is correct, try changing the frequency of either oscillator and see if that changes what you are hearing when you stop turning the knob. After that, try it on Osc 1 and 3 and then Osc 2 and 3.
If this is what you are hearing then this is precisely what you pay for when you buy an analog synthesizer. This is the sound. I don’t know you or what your experience level is with analog boards but you could be referencing what you are hearing to a digital synthesizer or something like that. The nature of analog is that it is organic and alive and evolving and not as pristine sounding as something that you might hear coming from a digital synth.
This sound between the oscs, this is what makes analog synths…especially those with more than 1 osc sound so gravy. It is very much like having 2 guitarists play the exact same thing.
Eric
i dont think it is it
it sound like heavy LFO modulation on the wave form, and it happens also when the 2 osc have the same wave form
even if i just play short notes in a rhythm, it changes very strongly every few notes
can you record an audio demo and send us a link to it?
Eric
As Erick said, cross modulation between Osc’s is normal on analog oscillators. The only way to tune Osc2 or Osc3 to Osc1 is by ear, move the frequency knob of osc2 or in very small steps until the cross modulation becomes next to nil. The phenomenon is that when Osc2 is just a tiny bit off, you hear some lfo-like modulation.. Osc1 generates say 1000 cycles per second and Osc2 generates 996 or 1003 cycles. The fact that you are using presets does not change the fact that an exact midi value translated to even a proper voltage still is subject to hardware variations : it’s analog.
Try this, set Osc1 and Osc2 to say 16’, then try to tune them perfectly with the Osc2 frequency knob and your ears. If you don’t want to go through that process when performing, use the 1-2 sync switch, this way, Osc2 will always start in sync with Osc1 and the tiny portion of the uncomplete or “over-complete” wave of osc2 will not matter. Do this test with exactly the same wave form on both Oscs, otherwise, you are including new variables in an already complex equation.
When using 1-2 sync with different octave setting on Osc’s, if Osc 2 is higher frequency than Osc 1, osc2 will generate 2 waves for each of Osc1 (or 4, or 8 or 16 etc.). If Osc2 is set to a lower frequency, it will only generate half a wave, or a quarter and so on, making the oscillator almost silent. Uncomplete waves that do not cross the 0v line toward -voltage are not fully qualified frequencies and are usually silent, sometimes artifact noise. The detune effect was quite strong to me too in the beginning, but has been lessened quite a bit lately, probably because the unit is on 24/24. I think it’s been a couple of weeks last time I turned it off.
Finally, if your problems are of a magnitude greater than what is supposed to be, that would lead me to believe your Voyager is in need of calibration. Look into the auto-tune feature and see if it helps. I can’t comment too much on that process, my Old School does not have it.
thanks a lot again for your help everybody
this is the link for the audio file:
https://rcpt.yousendit.com/761541585/3e61c6897aacfbc70039384bd77d80ae
this is the link for an image of the wave form of the audio file:
https://rcpt.yousendit.com/761542257/05bc2914392eb6f66a80767efc9e832f
again, my problem (if it is one) is a strong modulation between osc 1 and 2 in the “initial parameters” factory patch
I listened to your file. What you are hearing are two sounds of almost the same frequency slowly reinforcing, and then canceling each other out. This is because the oscillators are very slightly out of tune with each other, maybe by about a hertz, or even less. This is absolutely normal, and absolutely essential to the organic sound of the analog synth!
Try to forget the midi numbers on the screen, and remember that it’s an analog synthesizer. It isn’t going to be exactly perfect, and it isn’t supposed to be. That’s its charm!
Play it with your heart, and your head will begin to appreciate the small descrepencies.
I have written a more technical reply to this, but I think mayidunk said it best, so I will carry only this : what you refer to as a problem, i would qualify simply as a ‘characteristic’ of the product.
its been awhile since ive played a voyager ( 
) but that is pretty normal, there might be a little extra drift in the frequency but nothing serious. how long do you let the voyager warm up before you start playing? and have you ever calibrated/tuned it? and i dont mean tuning it from the front pannel, there should be trim pots somewhere on the back to get a more precise tuning, correct me if im wrong guys
Okay,
I listened to your audio file too, and just like what we have said, this is a chorusing effect that is as natural as when any two sounds of the same frequency play at the same time.
The term for this is Beat Frequency.
http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/beat.html
CHeck this out too.
http://en.wikipedia.org/wiki/Interference_(wave_propagation)
Your recording:
Osc1 is putting out a waveshape at a certian frequency. That waveshape cycles, giving you your pitch.
When you engage Osc 2, the cycling waveshape of Osc 2 competes with that of Osc 1 creating a chorus effect.
This is the desired sound of an Analog Synth. This is not frequency modulation or anything, this is just what happens when two waveshapes of similar frequencies encounter eachother.
Now this does sound like your Osc 1 and 2 are SLIGHTLY detuned on the init paramaters. However, since you know this now, you can make sure that Both Oscs register at 0 on your display. This won’t eliminate that sound that you hear, it will probably minimize it a tiny bit.
See, the reason why your midi display is important is because analog Oscs are extremely difficult to calibrate directly to their panel settings. This is why people have logged on here and asked Moog why their oscillators are all set to zero (on the panel settings) and they are not the same pitch. You can call Moog and ask them that question yourself, but Amos has already explained in this forum that while the panel settings on the Voyager might be slightly off, setting the numerical value on the display to 0 when you turn the freq knob will make sure they are perfect, even if they don’t perfectly line up with eachother on the panel settings.
You can look at your midi display value for that Oscs frequency, or better yet you can rely on your ears. Either way you won’t eliminate that type of sound and its NOT a problem with the synthesizer.
This is the sound that people pay for when they buy a 2 osc Synth.
Eric
CF,
There are no holes on the back like on the Micro. I think calibration is done by popping the hood with a scope. Don’t we wish it was that easy? lolol. By the way I don’t think my Micro has EVER had any calibration since we have owned it. Probably could use some.
OK, i understand it is not a problem (anyhow, nothing can harm my warm relations with my voyager)
but a technical question: when i record something like bass line for electronic music, this cyclic wave cancelation is a little disturbing because it almost eliminates the bass line for a short time (and this can be important if the track is based on the bass line)
any tip for that?
Tip 1: Sync them. Sort of a workaround but it works in some cases.
Tip 2: Complete cancellation is more likely to happen if the volume of the oscillators are equal. With maximum 10, maybe OSC 1 = 8, OSC 2 = 5-6 will eliminate the problem
Tip 3: Complete cancellation is more likely to happen if the oscillators are in the same frequency. Maybe tune the second oscillator one octave above (or below - I think that trick first became known in the Yamaha CS synths)
Tip 4: Again complete cancellation is more likely to happen if the waveforms are the same. Process one of them so that it has different harmonics. Or use another one, something like a triangle or sine.
Of course you can use any combination of the above.
In some synthesizers (most notably analog ones) you can sync the phase of the oscillator to the keypress. Basically, what the oscillator needs to sync to something, is a transient (i.e. a short impulse, or the rising spike of a saw, or a pulse, or an envelope of extremely small duration and so on).
Oscillator beating is an acoustic phenomenon and it can never be completely eliminated (as far as I know). The above tips can help you a lot though.
Yannis.
i am always amazed by the serious help i get here !
Thats phase cancellation. THat is where one wave cancels out the amplitude of a second.
The New Taurus Pedals as did the Old T1’s are supposed to give you that phasing, but without taking the bass away. I don’ t believe on these types of Oscillators you can eliminate that. I could be wrong though.
I think if what I read while searching for info for you I came across this filter that is supposed to be for video, and it is a Phase Cancellation filter, which eliminates the cancellation, which is probably how the Taurus pedals got around this physical problem.
Im just speculating here though.
Eric
Please see my edit at the end of this post.
I took a few minutes and sat down at the synth to see if I could make any adjustments that would either eliminate or reduce the phasing/beating effects caused by two oscillators tuned to nearly the same frequency.
Experiment #1: Oscillators in Unison (tuned to zero beat).
With careful tweaking I was able to adjust the pitch of Osc. 3 to Osc.1 so that no phasing occurred (unison tuning or zero beat). Both oscillators were set to the same wave shape and same mixer level. While this was possible, I noticed at least two things: 1, that eventually the two oscillators started going out of tune with each other, and 2, that even though I could tune them exactly, there was no way to control the phase relationship between the two. In other words, one osc.'s phase might be set to 0 degrees, while the other osc. would end up 35 degrees out of phase with the first osc. This is an issue because this means there is no way to determine if in the end one osc. is reinforcing the other or canceling the other.
Experiment #2: Oscillators in Unison with Mixer Differences.
I again tuned them in unison, with the same wave shape, but different mixer levels. The result was that though a reduction of the phasing sounds occurred, in reality all I was really doing was removing the sound of one oscillator, thereby eliminating it and losing the power of oscillator stacking in the resulting sound. This defeats the purpose of using two or more oscillators.
Experiment #3: Oscillators in Unison with Different Wave Shapes.
This yielded a possible result. I again tuned to unison, set the levels to match, and started playing with using different wave shapes. What I discovered was that the only combination of wave shapes that might produce an acceptable result was if one osc. was using a triangle wave and the other used anything but a triangle wave. This eliminated the very apparent phasing artifacts of the high frequency harmonics, but left a low frequency phasing that while not so apparent, was still noticeable.
Conclusions:
-
Perfect unison tuning between oscillators is possible but not reliable, and cannot guarantee that the resulting timbre will be repeatable.
-
Different mixer levels can eliminate the phasing, but defeats the purpose of using more than one oscillator.
-
Different wave shapes can reduce the phasing effects as long as only one oscillator is set to a wave shape that produces high frequency harmonics and the rest are set to a wave shape that does not. However, even this solution still produces low frequency phasing artifacts.
-
I was able to figure this out in 5 minutes at the synth with a little creative experimentation.
-
Part of the fun of using an analog synth is experimenting with it and asking your self, “What if…”
Can I step on my soapbox for just a minute? Feel free to stop reading if you’re not interested… I’ll understand.
Begin Rant:
A lot of people using computers with software like Ableton, etc. kind of get into a groove of expecting “apparent perfection” in their results. I say “apparent” because the digital domain can only provide an approximation of an analog event, it can never achieve enough resolution to ever exactly model an analog event. Yes, it can come really, really close, but in the end the digitized analog waveform is only a collection of discreet samples taken in different timeslices, with the values of the resulting holes in the overall sample being inferred.
Some people have been conditioned to believe that the computer is the final arbiter of what is correct and what is not. Take the case of the screen shots that Amotz provided. You can lay a ruler across the graphics of the two waves and think that because the wave shapes line up exactly, they must be in perfect tune with each other. The reality is that after a certain point, the softwar stops measuring the accuracy of the source signals, and starts measuring its own limitations! Because of the nature of digital sampling, the software is only as accurate as the sampling rate of the sound file, and the ability of the software to accurately interpret the data in the sound file based upon rules and conditions that were previously coded into the software. These rules also determine how the software is to infer what isn’t represented in the data in the sound file. Remember, the software is only processing a dataset of discreet, numeric values. It is an exercise in indirectly inferring reality versus experiencing actual reality. Is it close enough? Of course it is, for the most part. Is it an actual depiction of reality? Not quite, as that which is left out is inferred. Inference of an event is an educated guess at reality based upon events that occur before and after the particular event being measured.
Why the rant? Because too many are learning to rely on tools to depict reality for them. It stifles their creativity and willingness to experiment because they have been conditioned to not rely on their senses or natural ability. I could’ve spent much time trying to figure out on a computer why Amotz is having this difficulty. I could’ve analyzed the two sound datasets to see if could find differences between values sampled at the same timeslice, and if I did find differences in the data (if!), I would hopefully then be able to determine the nature of the differences, and then hopefully be able to correlate the results into a meaningful hypothesis of what is occurring.
However, our brains and senses are so exquisitely acute that just listening to the two sounds immediately provides the clues as to what the problem is. Of course, this presumes that the listener has previously learned how to interpret what they’re hearing. But then again, the same holds true for anyone attempting to interpret the results provided by the software, and the person who wrote the rules into the software’s code.
In the end, I find that if I get my head out of the digital tools, and stop trying to make actual reality align with what the computer says is reality, then my creative juices are flowing, and I am now creating and playing musical instrument_s_, and not a laboratory instrument. I’m also training my senses to accurately interpret events as they happen! Of course your mileage may vary, but feel free to have fun while determining by how much.
Experiment, play, have fun, learn things by the seat of your pants using only your senses, your brain, and your creativity! Learn by doing. Train your senses. Get your head out of the computer!
For those of you still reading, thanks for letting me rant. Feel free to smack me back into reality if need be. I have my fireproof undies on, so it shouldn’t be too bad.
End Rant:
I now return you to the existing thread… already in progress.
Bob
Edit:
I have to back pedal a bit…
While what I said above about sampling and software is basically true, it doesn’t really reflect what’s possible using Fourier Transforms and the like. Indeed, if Amotz is even able to adjust the time scale of his wave displays in Cubase so that only one or two cycles are displayed, he would probably be able to see the phase differences himself, especially if Cubase allows him to display both waves superimposed on each other in the same window.
Anyway, grains of salt are available upon request. 
Bob
Miya,
Thats definately thorough. Most of the time I have noticed that if the waveshapes and frequencies were closer to exact, the phising was minimised. It was with different waveshapes that I noticed the most phasing. Gotta love the ol trusty triangle wave.
I don’t knkow how to use a scope, I have never seen one in use except on Mr Wizard and on various youtube videos. Based on the information that I provided in the links about waves and phase cancellation, what I saw on those links didn’t match up to what I saw on the image provided by amotz.
Your rant could be referring to the differences between a cheap techtronix and an expensive one. Imagine what the scope would read if it was accutately showing the relationship between those two waves, the result wouldn’t be symetrical like his was. Im thinking like it is a dual channel digital osc with a color display, wouldn’t this accurately show the cancellation?
I see your point too.
Eric
Thanks, Eric.
A dual trace O-scope of just about any caliber should be able to accurately show the phase differences between the two oscillator signals quite easily. I was referring to software on a computer, similar to the jpeg image that amotz listed earlier on in the thread. That image was of software that was showing different views of the two wave forms in several windows, if I recollect correct.
Bob
BTW, who’s Miya?
I would imagine that a dual trace digital o-scope would also show the phase relationships between the two signals as the time axis was shortened in order to magnify the wave shapes to where less than a few cycles were being displayed. And actually, if Cubase is able to do the same, it might also be able to show the phase relationships. Amotz’s image is a Cubase screen shot.
Amotz : if you can post the same file or similar file in .WAV format, i’ll run it through my spectrum analyzer and show you what phase shifting looks like.