one more thing

[amotz]

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?

[amotz]

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
???

[EricK]

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

[amotz]

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

[EricK]

can you record an audio demo and send us a link to it?


Eric

[Portamental]

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.

[amotz]

thanks a lot again for your help everybody
this is the link for the audio file:

https://rcpt.yousendit.com/761541585/3e ... 4bd77d80ae
this is the link for an image of the wave form of the audio file:

https://rcpt.yousendit.com/761542257/05 ... 7efc9e832f

again, my problem (if it is one) is a strong modulation between osc 1 and 2 in the "initial parameters" factory patch

[mayidunk]

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.

[Portamental]

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.

[ColorForm2113]

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

[EricK]

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/hb ... /beat.html

CHeck this out too.
http://en.wikipedia.org/wiki/Interferen ... opagation)

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.

[amotz]

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?

[ikazlar]

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.

[amotz]

i am always amazed by the serious help i get here !

[EricK]

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