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U-He Diva vs Boog Model D: Oscilloscope Waveforms
Old 21st January 2019
  #61
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Quote:
Originally Posted by Synthbuilder View Post
frequency of the note
Look at the bottom.
One cycle takes about 4 miliseconds.
So it is 250Hz.

And to determine if it is the Gibbs or something else on the Minimoog side, sample the synth at different sample rates (96Khz,192Khz).

Since i don't have the Boog, i just rendered the Xhip (it is very similar to Diva in this field) at 192000, then 44100:
Attached Thumbnails
U-He Diva vs Boog Model D: Oscilloscope Waveforms-ripples.jpg  
Old 21st January 2019
  #62
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monomer's Avatar
 

Quote:
Originally Posted by Synthbuilder View Post
I have just checked and Diva does indeed produce some wiggles at the top of the waveforms that are not altered by the synth's filter frequency. This, therefore, is not representative of monitoring the output of a real analogue device.
It never was. OP was talking about Gibbs phenomenon, which occurs when bandlimiting a signal.


Quote:
I am guessing that this is to do with the band limiting of the software involved but this is not my area of expertise so this really is a guess. However, Diva does also produce wiggles that are representative of the synth's resonant frequency and these are added to the other wiggle.
In the screenshots you see no effect whatsoever from Diva's main filter.
They are exactly the same even if i set a HP filter and set the cutoff to a very low value.
And they are there with absolutely no resonance applied.
If this is a surprise to you then you probably want to read up on sampling. These wiggles are a (well described) consequence of how sampling works.

Quote:
Turning up the resonance will accentuate these wiggles,
But the resonance was not used in the pictures of OP.

Quote:
But the OP seems to be really asking why the two waveforms are different. And that is a good question and I don't think it can easily be dismissed as some sort of issue with pre or post ADC filtering.
You just told us this is not your area of expertise, so how can you be so sure?
Maybe it would be interesting for you to read about digital non-causal filters.
Old 21st January 2019
  #63
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BTW Shouldn't a good hardware oscilloscope have bandwidth of several Megahertz ?
That would not give a low frequency audio signal any ripples even at the sudden jump in voltage at the start of the wave cycle.
Old 21st January 2019
  #64
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JayTee4303's Avatar
If you bring negative comments to wave theory discussion, enjoy your world, music, and... byte me.

Back your O'scope up with a Spec-A. You're only seeing half of what you need to with a snapshot of one wave train.

Then, accept your instruments for what they are. "Why this does what it does" is useful if it helps you express yourself thru music. Trying to change what it does intrinsically is the path to frustration.

Rock the chick you brought to the party.

Use your tools to deeper understand her, and take her to new and unexplained waveforms. Use your ears ALONG WITH your eyes to construct basic waveforms as foundation, the use the resulting awareness to explore new territory.

Put another way... listen to the difference between the Gibb squiggles and the Gibb-less squiggles... if you can hear it... and then listen to the difference between square and saw.

Where does the pay-off live?
Old 21st January 2019
  #65
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Synthbuilder's Avatar
Quote:
Originally Posted by Mutantt View Post
Look at the bottom.
One cycle takes about 4 miliseconds.
So it is 250Hz.
I see it now. I couldn't see the little text on my laptop screen when I made the first reply.

Quote:
Originally Posted by monomer View Post
It never was. OP was talking about Gibbs phenomenon, which occurs when bandlimiting a signal.
I understand that now. I just assumed that the guy had plugged a digital scope into the audio output of his Boog and his computer interface and compared the two. This was an incorrect assumption.

Old 21st January 2019
  #66
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zerocrossing's Avatar
Quote:
Originally Posted by gentleclockdivid View Post
Noww c'mon, let's be honoust
It’s true! I mean, not none at all, but I find the discussion here to be more interesting, for the most part. When I got to a point where I invested in a good analog poly (Prophet 6), I actually sold my Diva license. Partially because of the sound, but more because of the interface. I find it’s UX design to be a bit of a mess, especially the modifier section. If you have a knob that says it’s modulating “lag,” you have failed. I actually started a comp of what I thought that section should look like (I removed it), but the Divites and Urs were so hostile to me that I abandoned the topic altogether. What I basically found was that I was mostly going to Zebra HZ a lot more than Diva anyway, because of it’s extended feature set and better (but still not great) UX design.

So, I’ll visit KVR when I’m looking for something specific, or just bored, but I do tend to miss a lot of what is happening there. If Urs adds a ultra-divine mode where the audio rate modulation is more on par with RePro, I’ll buy a license again, but I hope he also tightens up that UI a bit.
Old 21st January 2019
  #67
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monomer's Avatar
 

Quote:
Originally Posted by Synthbuilder View Post
I understand that now. I just assumed that the guy had plugged a digital scope into the audio output of his Boog and his computer interface and compared the two. This was an incorrect assumption.

Glad to see you figured it out!
Old 21st January 2019
  #68
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DrJustice's Avatar
 

Quote:
Originally Posted by Mutantt View Post
BTW Shouldn't a good hardware oscilloscope have bandwidth of several Megahertz ?
That would not give a low frequency audio signal any ripples even at the sudden jump in voltage at the start of the wave cycle.
A high bandwidth scope is always good if you want to see more details [1].

Assuming that by low frequency signal, you mean low bandwidth signal, then not really. The higher bandwidth the source signal has, the less wiggles you get - if the waveform does have straight lines, or rather sharp discontinuities, that is. Just like when you reconstruct such a signal with a high bandwidth, as you show in your posting #61.

Basically, the higher the bandwidth of the source signal, and the scope if measuring, the more higher harmonics gets through to "fill in" between the wiggles and make straighter lines.

[1] That more detail (higher harmonics) leads to less wiggles and straighter lines may seem counter intuitive at first.
Old 28th January 2019
  #69
Urs
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Quote:
Originally Posted by kraze View Post
until we have someone emulating how electricity itself behaves - analog synthesis will require analog synths.
Electricity is one of the best understood physical phenomenons in the universe. It's easy to observe, there are plenty of formulas and known effects to any level beyond human perception. I think we can nail analogue just fine - by using the exact same equations which the engineers used to put toghether that synth.
Old 28th January 2019
  #70
Urs
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Now, about those ripples...

If you could tap into Diva and get the direct output of the oscillators, you would see nicely symmetric ripples on both sides of the phase wrap. That's because the oscillators use a linear band-limiting filter.

But because each stage within Diva is individually oversampled, there are measurable phase shifts above 10kHz. And because the signal always runs through the filter, there are more phase shifts above 10kHz. And thus, the ripples which were originally all symmetrical are moving over by a few samples.

There you go
Old 1 week ago
  #71
For as good as diva and repro are. I'm going to say it. They still are not as good as the real thing, the boog, and the neutron(it uses prophet vcos) Smoke repro and diva on the girth and fluidity of the filters and the smoothness and aggressive envelopes.

To be honest, i like hive more, because it does new stuff analogs do not and is so varied. Diva is very cool and i keep it around strictly for the jp8000 osc for strings. And occasionally the obhie filter, but man bx oberhousen is so good that i prefer it.

I wish the presets in Diva were as good as the ones in hive :(

Still the model d is like synth heaven, huge sweet spot something about it just is awesome.

DF
Old 1 week ago
  #72
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That Urs fellow is smart.
Old 1 week ago
  #73
Quote:
Originally Posted by Bignatius View Post
That Urs fellow is smart.
Indeed, in fact to me, he is the single reason i never abandoned software synths.

U-he simply is the best over all, but i still love the roland cloud stuff as much.

DF
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