A misconception about the model D

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Kevin Lightner
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A misconception about the model D

Post by Kevin Lightner » Fri Apr 01, 2011 3:36 pm

It has been stated before that the "punch" of the Minimoog is due to it overdriving the filter.
While this may be true of earlier models, later models had a modified gain structure which lowered the filter drive.
(this is verifiable by reading the factory production change sheets or inspecting older and newer Minimoogs.)

I have found that the "punch" of the Minimoog is due to the attack portion of the envs exceeding the maximum available sustain level. Anyone with an oscilloscope can verify this. Simply probe the env CVs and you will see they go higher than the max sustain, then come back down.
One can even hear it do this without a scope by listening to the filter.
Set up a long attack and maximum sustain.
On an unmodified Mini, the attack portion will go past the maximum sustain level, then very quickly come back down.
Both env generators do this.
I have often "fixed" the filter envelope to be correct, but never mess with the VCA env as it would remove this "punch."

In short, the envs have a design error and any tech or stock Mini owner can easily verify this.
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LivePsy
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Re: A misconception about the model D

Post by LivePsy » Sat Apr 02, 2011 2:50 am

Hi Kevin, how is this different to setting the sustain level lower than maximum? By your description it sounds exactly like setting the sustain to 9 instead of 10.
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Kevin Lightner
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Re: A misconception about the model D

Post by Kevin Lightner » Sat Apr 02, 2011 6:17 am

Yes, you're correct.

Because the attack portion will overshoot even the highest setting of the sustain control (the maximum possible), it doesn't follow the classic description of an ADS or ADSR where the attack should never exceed the maximum chosen sustain level.
That means when sent to a VCA, there will be a short spike of volume that's louder than the maximum sustain level.
If the sustain level was to, say, "go to 11", this effect would probably not be noticeable.

In the VCF env, resistor R13 is normally 4.7Kohms.
But it should really be closer to about 3.7Kohms.

The same resistor in the VCA env section would be R47, but I've never had the desire to swap it with any other value for fear of removing this "punch."
Better to be king for a night than schmuck for a lifetime. - R. Pupkin

LaxSlash1993
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Re: A misconception about the model D

Post by LaxSlash1993 » Sun Apr 03, 2011 12:45 am

Interesting. It would be cool if there was some kind of software update for the Voyager that would add a menu setting that would cause it to do this if turned on by the user.

LivePsy
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Re: A misconception about the model D

Post by LivePsy » Sun Apr 03, 2011 3:46 am

Err, didn't we just say it can be done with the sustain on 9 ? You can dial in your own punch that way. Amusing how a design flaw gets to be revered as mojo.

Seems like it won't sound right unless the knobs all go to 11 :D

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Rob Smith
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Re: A misconception about the model D

Post by Rob Smith » Sun Apr 03, 2011 8:23 am

It's imperfections are what makes it sound so perfect. I guess, it's almost human. :D Thanks Kevin, I never knew that about the Mini.

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Re: A misconception about the model D

Post by torinkrell » Sun Apr 03, 2011 1:04 pm

As I have always understood it, the unusually fast attack of the Minimoog envelopes along with an unusual 20-25 ms hold at the attack's peak level, rather than a spike, is what give the mini its punch. Kevin's observation explains why this happens even when the sustain level is set at maximum. This psychoacoustic phenomena is similar to how moderate peak limiting, light clipping and analog tape saturation can also impart more perceived punch to sound transients.

I believe the PAiA Fatman uses a Punch switch using this psychoacoustic effect, and I remember an article by Craig Anderton with graphic measurements investigating and substantiating this theory of the Minimoog's amazing punch.
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Kevin Lightner
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Re: A misconception about the model D

Post by Kevin Lightner » Sun Apr 03, 2011 2:44 pm

There is no flat spot in the env. Perhaps the VCA doesn't continue to amplify past a certain CV level... I haven't checked that.
But if you set all the VCA's envs at minimum,, one doesn't get a longer sustain.
Like most synths, one just hears a small blip of sound- as one should on any synth.
But this is something EASILY heard by anyone with a Mini if they listen to the filter.
It doesn't matter how long the attack is. It could be 8 seconds and it will still do this.
Simply take a Mini, dial up a long attack with the sustain full.
The attack will go PAST the sustain level, even if set to max, then comes down to the sustain level.
An attack should rise to the sustain level, not exceed it.
Don't take my word for it, try it.
Better to be king for a night than schmuck for a lifetime. - R. Pupkin

nick braithwaite
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Re: A misconception about the model D

Post by nick braithwaite » Mon Apr 04, 2011 10:37 am

Hi Guys; I may be barking up the wrong tree here - or more likely, just barking :wink: - but ref. Laxslash asking about giving a Voyager the same punch, you can certainly add some considerable extra punch using Oscillator Sync. with the Voyager. I have been doing this a lot. I dare say it is not quite what you are talking about but it can be very effective. More generally, Osc. sync. can help with many timbres & I cheerfully admit to using it a lot. I'll quite often try it when making a new patch, just to see if it helps which it often does. The effect can be quite piercing, almost brutal, but with some experimenting you can produce several surprisingly more subtle effects. The combination of the slave osc.'s frequency control (working as a wave-form control in this mode) and the filter controls can produce articulations that perhaps one might not expect without a more complex filter. When I first came across this, I rather missed some of its qualities but a passage in Jim Aikin's book encouraged me to explore more fully and I have found it to be a very flexible & useful tool. I dare say my more experienced peers already know this only too well, in which case forgive the intrusion! I keep finding new things to do with this principle - it is well worth taking some time with - it can seem limited at first. BTW - Hats off & drinks all round to Jim and all those who recommended his book when I was struggling; although there's lots of digital, soft and virtual in it, there are analogue-friendly tips in there, even if to a newbie it is not always easy to unravel them. Hope this helps. Cheers, Nick.

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Kevin Lightner
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Re: A misconception about the model D

Post by Kevin Lightner » Mon Apr 04, 2011 9:54 pm

Fwiw, there is some value in modding the VCF's env to be correct.
One can synthesize much truer siren sounds with the emphasis (resonance) cranked full.
Certain pizzicato type sounds, bird chirps and others can be more truly synthesized.
It's better when used for a long crescendo type filter sweep also.

I usually install a trimmer in place of the old resistor in order to dial it in exactly. (But I only do it on the VCF env, never the VCA env.)
Not surprisingly, many synths already have such a trimmer inside, including the Moog 911 modular envelope generator.
Take a look at what trimmer #2 does, both in description and in the pictorial provided:
http://www.Minimoog.net/911.gif

This is exactly what Moog got "wrong" in the Mini D, but it made it all the more right.
The VCA has more punch and you can never dial it completely out.
Sure, one could dial in more of this punch by cranking down the sustain level and playing with the decay, but my whole point has been that you can't get rid of it (on a stock Mini.)
It's part of the character and magic of the Mini and one of the little, subtle details why so many Mini clones never quite nailed the Mini sound.
I doubt many virtual software Mini clones incorporated it either unless they discovered it themselves.

I know of another probable oversight by Hammond B3 clones that's sort of like this.
I'm no Hammond wiz, but it's one of those things only an engineer or tech would probably ever notice and thus it doesn't get modeled in VA perfectly by programmers.
Better to be king for a night than schmuck for a lifetime. - R. Pupkin

sunny pedaal
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Re: A misconception about the model D

Post by sunny pedaal » Wed Apr 06, 2011 2:19 am

nice , at last an writing on the important influence of ( analogue ) envelops on the sound.
more often then not this part of the synthesizer is neglected .
I did some tests with the a6 andromeda ( digital but very exciting possibilities ) and it's really amazing how much difference the different slopes of the different parts of the envelop cause to the final sound

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