'Real' circuit simulation

[clintrubber]

This one's about realtime mimicing analog hardware by a computer.

Obviously circuit-simulations are nice, but wouldn't it be cool to have realtime emulation ? We have of course plugins, but as far as I know all of these are modelling the behaviour, so are not 'circuit-in/signalprocessing-out'.

I'm at least not aware of stuff that does it like that.

Anyone knows of computer-packages with which you can for instance draw a circuit, plug in a guitar and play thru the circuit, tweaking the controls as you go ?

First thing like that that I've seen is Korg's CMT (Component Modeling Technology), already from a few years ago.
"Korg's CMT tries to replicate every part of the original, every transistor, resistor, etc. to virtually recreate the MS-20's circuitry and thus - its sound!"

Dunno if it's really working like they say it's working, but let's give them the benefit of the doubt.
I could imagine though that it'd require quite some processing power, so some corners would have to be cut.
This software does load a computer though, so it might be true indeed that it's doing as advertised (weird reasoning :wink: ).
Of course it'd make little sense to model straightforward circuits on component detail if the analog randomness/parasitics/noises aren't taken into account. There is an 'analog' control added to the software to insert some randomness to the VCO's & VCF's, so all analog behaviour from the components won't be taken along and then brought back in later by this control.

So back to topic, anyone knows of stuff that 'really' simulates ? I'm aware of programmable analog hardware but that's not the same - I'm curious to software that's based on circuit-entry and at least captures basic functionality in real time.

Bye,

Peter


BTW, more on that Korg bundle here:

http://www.vintagesynth.com/korg/legacy.shtml

For some weeks now I'm the owner of that Korg Legacy bundle, which
is in essence several software synths and an uberfunky controller (a 84% USB-connected replica of a Korg MS-20 monosynth).

I hadn't expected I'd ever spend money on anything synthlike, but that controller made me do it. I'm not fond of synth-based music (to say the least), but I couldn't help, the tech-side of things does interest me.

That controller doesn't pass anything audio, it's purely a controller, but the integration is so transparent that it makes you think the sound is coming from that box itself.

You can even use the extensive patching-field: plug away with real patchcords and the computer senses & reacts accordingly (and of course draws the cords onscreen). According to reviews of people comparing the real & emulated MS-20, even patching-abuse (making totally illogical connections) is emulated correctly, so I guess that might best be emulated by mimicing the actual circuit. Just guessing here though.

 

[alk509]

They had like 4 or 5 MS-20s when I was in school, and I LOVED them. I got to use one of those legacy bundle thingies a few months back, and it brought back some very, very good memories! :thumb:

Peace,
Al.

 

[clintrubber]

[quote author="alk509"]They had like 4 or 5 MS-20s when I was in school, and I LOVED them. I got to use one of those legacy bundle thingies a few months back, and it brought back some very, very good memories! :thumb:

Peace,
Al.[/quote]

Good to hear from someone who has used both that the Legacy-version makes sense. :thumb:

It's still of course a softsynth, despite the tasty controller. But having that dedicated control-box available makes all the difference to me.
Someone has kindly provided a PolySix control-overlay as well, so the same controller doubles nicely for the included PolySix-softsynth as well.


In addition, prices have decreased on these bundles (rohs-related as it seems... :shock: ) so these things are a good deal. Perfect for someone like me who understands the tech-side of the various building blocks but who has little experience so far with actually using these things for some music. And I haven't even really started putting external signals through them :wink: Lots of fun ahead.

Comparable results could of course be had with 'generic' controllers (those Beh.-MIDI-boxes for instance), but that's not as s*xy imho.


But OK, anybody ever seen any circuit-in/processing-out things so far ? As far as I've seen this seems the only one so far, but that can't be true.
I seem to recall alike claims of the various amp-modellers/FX-emulations (POD, V-Amp, Line6-floor-FX etc) but I don't know if they really approach things on a circuit-basis.

Bye,

Peter

 

[kruz]

well..
all can i say is that i have a real ms20 and tried it side by side with that plug.. and dialing the same settings ends to really different results.
That virtual ms20 doesn't sounds bad at all.. but it's not a real ms20 replica as they are saying

 

[Mendelt]

Hey! DSP .. I don't know a lot of electronics but I do know DSP :grin:

I think 'real' circuit simulation is still a bit to slow to do realtime. and there are problems....

I've seen some examples where people use the s-domain transfer function of a circuit (usually a filter) and then use a bilinear transform to get the z-domain transfer function so you can make it into a digital filter. That way you can model the linear behaviour of a circuit (with some limitations when you get close to the nyquest frequency)

Of course linear is dull and things only start to sound interesting when stuff becomes slightly nonlinear. The problem with modeling nonlinearities is that they cause harmonics. And the problem with harmonics is that they are sometimes higher in frequency than the nyquest frequency. So they will fold back and cause nasty aliasing. The only way to get around this is to upsample before the nonlinear part and then downsample afterwards with a good antialiassing filter to get rid of the harmonics above nyquest. This is quite slow so most plugins cut corners here and they don't sound very good.

 

[chrissugar]

I had the same experience like Kruz.
I stil have two real analogue MS20s, and tried them side by side with my friends new plugin plus controller. If you listen to the emulation in isolation it seems to sound very good, and in fact it is one of the very few good sounding plugins, but when you compare it to the real thing, the difference is night and day.

chrissugar

 

[clintrubber]

[quote author="kruz"]well..
all can i say is that i have a real ms20 and tried it side by side with that plug.. and dialing the same settings ends to really different results.
That virtual ms20 doesn't sounds bad at all.. but it's not a real ms20 replica as they are saying[/quote]

Hi,

I understand what you're saying. And of course I don't want to give the impression that I feel I now have a software-bundle that makes all 'real' analog synths obsolete, for sure I won't.
I did got the impression though that this stuff will at least give me a nice first step into that world and while it may not perfectly resemble the real stuff (be that 90% or just 5%), that's all OK for what I want to get from it.

And while I like the various feedback on those new toys here I do realize I might have overemphasized that Korg-thing.
I mean, it was only meant as a possible illustration of that 'real' simulation of circuitry. From Mendelts reply I understand it might still be a bit too early. And those things that might be possible now aren't special enough yet.

Bye,

Peter

 

[clintrubber]

[quote author="chrissugar"]I had the same experience like Kruz.
I stil have two real analogue MS20s, and tried them side by side with my friends new plugin plus controller. If you listen to the emulation in isolation it seems to sound very good, and in fact it is one of the very few good sounding plugins, but when you compare it to the real thing, the difference is night and day.

chrissugar[/quote]

Thanks as well for the reply. Could imagine what you're hearing.
Just curious (and this isn't meant as some smart-ass remark), how big are the differences in sound between those two hardware MS-20's when set to the same settings ?

Thanks,

Peter

 

[clintrubber]

[quote author="Mendelt"]Hey! DSP .. I don't know a lot of electronics but I do know DSP :grin: [/quote] :wink:

Of course linear is dull and things only start to sound interesting when stuff becomes slightly nonlinear. The problem with modeling nonlinearities is that they cause harmonics. And the problem with harmonics is that they are sometimes higher in frequency than the nyquest frequency. So they will fold back and cause nasty aliasing. The only way to get around this is to upsample before the nonlinear part and then downsample afterwards with a good antialiassing filter to get rid of the harmonics above nyquest. This is quite slow so most plugins cut corners here and they don't sound very good.

And do I understand it correctly that we're then only still talking about 'stationary' circuits ? I mean, when we're tweaking knobs in real time the realism/accuracy is even more difficult to obtain ?
It may mean for instance that that Korg example starts from the idea as described ('CTM') but simply needs to cut quite a few corners along the way to get things done.

Bye,

Peter

 

[chrissugar]

Hey Peter

Please don't take my opinion as a critic to the Korg bundle, I have to admit that I was impressed enough to think about buying it.
Of course, not for the MS20 emulation but because I think that for the money you have a great controller, and not only the MS20 emulation but also the Polysix and the Wavestation and that fx plugin. The best emulation of all is the Wavestation, but that is not a big deal because the WS was a digital synth at the origin.

There is some difference in sound between the two real MS20s I have, but the caracter of the sound is the same. When I say there is a difference between the hardware and the plugin, I think about the basic caracter of the sound. The hardware sound is organic and also when you use both the highpass and lowpass filters with high Q settings you can obtain some interesting random beatings that can't be reproduced with the plugin.
Also the "day and night" difference is only in my synth freak opinion (I have a synth collection :grin: ) so probably many users would not consider the difference that significant.
I still think about the possibility to buy it. :grin:

chrissugar

 

[clintrubber]

[quote author="chrissugar"]Hey Peter

Please don't take my opinion as a critic to the Korg bundle, I have to admit that I was impressed enough to think about buying it.
Of course, not for the MS20 emulation but because I think that for the money you have a great controller, and not only the MS20 emulation but also the Polysix and the Wavestation and that fx plugin. The best emulation of all is the Wavestation, but that is not a big deal because the WS was a digital synth at the origin.
[/quote]
Hi Chris, no offense taken. I realize very well that the 'assumed real simulation' example I gave above with this Korg-thing might have triggered a few "ho, now wait a minute"-reactions.

There is some difference in sound between the two real MS20s I have, but the caracter of the sound is the same. When I say there is a difference between the hardware and the plugin, I think about the basic caracter of the sound. The hardware sound is organic and also when you use both the highpass and lowpass filters with high Q settings you can obtain some interesting random beatings that can't be reproduced with the plugin.

Thanks for the added info. Could very well understand that - I can't imagine that the software 'analog'-function can bring all randomness back in.

Also the "day and night" difference is only in my synth freak opinion (I have a synth collection :grin: ) so probably many users would not consider the difference that significant.

I'm quite a newbie w.r.t. synths. Hey, just a few weeks ago I was more of a synth-disliker :wink: So you won't find me spotting all differences in nuances the few upcoming years.
As said, I think this package can be a great learning tool. Despite my interest from the tech-side of things, I know I wouldn't have been doing this amount of experimenting if it had to be done by either a generic less funky controller or by mouse or by the :evil: user-interface of an old Poly800 that's lingering around here.

I still think about the possibility to buy it. :grin:

chrissugar

Lusting for the polyphony ? Or the patch-saving ? Or the stacking of a MS-20 & a PolySix :wink:
But be quick then. Seems they're kind of dumping it now. I'm not sure, but the price has been lowered quite bit the last months - so as long as stocks last...
Could of course be a rumour, but I read somewhere (yeah,... :wink: ) that that controller may no longer be sold in the EU within a few months because of som non-RoHS-compliant components... (see, here I am, spreading the rumour further now, unconfirmed and all :? ).

I might have bought it for a higher price, but for what I paid it was a no-brainer.

Bye,

Peter

 

[pstamler]

There's a program called DC-LIVE that does signal processing on a more-or-less real-time basis. It's really designed for cleaning up recordings, but they do have some useful filters. Also some distortion generators, but in my experience the latter sound horrible.

Peace,
Paul

 

[Mendelt]

And do I understand it correctly that we're then only still talking about 'stationary' circuits ? I mean, when we're tweaking knobs in real time the realism/accuracy is even more difficult to obtain ?
It may mean for instance that that Korg example starts from the idea as described ('CTM') but simply needs to cut quite a few corners along the way to get things done.

Yup. If you want to do the circuit modelling really well you need to recalculate all the coefficients every sample. This gets slow really fast.
What they usually do is make control voltages run at a slower sample rate so you only need to calculate the coefficients every 4 or 8 samples.

They probably cut a lot more corners. I think they only modelled the linear part of the oscilators and the filters and then added some waveshaping. This will probably get you close enough to the real sound. I think the 'CTM' part is mostly marketing. But that doesn't mean they can't create something that sounds (a bit) like the MS-20.

There's a program called DC-LIVE that does signal processing on a more-or-less real-time basis. It's really designed for cleaning up recordings, but they do have some useful filters. Also some distortion generators, but in my experience the latter sound horrible.

Realtime DSP is no problem for most modern computers. Realtime circuit emulation for audio is more difficult. (and probably more difficult)

 

[Rossi]

I actually took a plane to Gothenburg Sweden to buy one of those Legacy Budles. Korg dropped the price in Sweden first. Two weeks after my return, they dropped the price in Germany as well. Still, I have no regrets. I always wanted to see Sweden, and Gothenburg is one of the prettiest places I've seen. Nice people, too, and beautiful, beautiful women.

I digress :grin: The Legacy Bundle sounds excellent. I never owned an MS20, but from what I've been told there are big differences between indiviual units, soundwise. That said, I don't really care how accurately they modelled the original. What's important to me is that the software sounds fabulous, better than some real hardware synths. Also, let's not forget you can do things with the software that the MS20 won't do. Play more than one note at a time for instance. Or create fat or silky pads using the unison function. Plus you get a Polysix and a Wavestation plug. Bottom line: if you want the original, always go for the original. But the Legacy Bundle is a fine piece of software plus a cool controller.

 

[clintrubber]

OK, so we've come full circle: 'CTM' most likely to be filed away as marketing jargon, together with the Adaptive Knees, Hidden Mic PreAmps, Interrogating Release Controllers and Extruded Headroom Sinks...

Let's hope technology will make it soon possible to really do that realtime simulation. Nothing wrong with breadboarding, but as an alternative wouldn't it be cool to have a more or less realistic way of putting in that real circuit topology and have a realtime emulation ? OK, some more patience...

I actually took a plane to Gothenburg Sweden to buy one of those Legacy Budles.

Drastic action :thumb:

Down to EU169 here, two weeks ago.

If you haven't already, be sure to fetch the PolySix-template from the yahoo-group. Someone made a nice overlay, together with a provided controller-map the MS20iC then doubles as a PolySix-controller.

Bye,

Peter

 

[gyraf]

If you're in Gothenburg Sweden, be sure to check out the "Radio Museet" - the radio museum. Not only do they have beautifull stuff, they also sell surplus parts (like tubes, meters, knobs and so on..)

Jakob E.

 

[Rossi]

?169 ? Holy Moses, gotta drive to the Netherlands! No wait, two controllers won't make my computer more powerful. Damn, it's software after all. :roll:

Hmm, Jakob, I think the Radio Museet could my next excuse to fly to Gothenburg :green:

 

[clintrubber]

[quote author="Rossi"]?169 ? Holy Moses, gotta drive to the Netherlands! No wait, two controllers won't make my computer more powerful. Damn, it's software after all. :roll:

Hmm, Jakob, I think the Radio Museet could my next excuse to fly to Gothenburg :green:[/quote]

I was surprised as well - had EU199 in mind and then the new store of the ever expanding FeedbackCentre-emporium (which happened to be opened right here in town) had it for 169. As said, surprisingly, since so far I've only seen them having prices above the thomanns etc.
Another reason to support the local store :grin:

Now how many retro-spares would EU30 buy ? :wink: Cool that, a museum selling goodies like that :thumb:

 

[clintrubber]

[quote author="pstamler"]There's a program called DC-LIVE that does signal processing on a more-or-less real-time basis. It's really designed for cleaning up recordings, but they do have some useful filters. Also some distortion generators, but in my experience the latter sound horrible.

Peace,
Paul[/quote]Thanks for responding. I had a look at it, looks versatile. As I understood it it's not taking its function from a circuit-topology, but I might have overlooked that.

Bye,

Peter

 

[Rossi]

[quote author="clintrubber"]
If you haven't already, be sure to fetch the PolySix-template from the yahoo-group. Someone made a nice overlay, together with a provided controller-map the MS20iC then doubles as a PolySix-controller.
[/quote]

:shock: Nope, haven't seen that template. Do you have a link?