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nitro27
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Joined: 10/11/2015 - 18:27
Karplus-Strong Synthesis in Modular

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en.m.wikipedia.org/wiki/Karplus–Strong_string_synthesis

So you send a burst of noise through a delay-filter feedback loop, with the delay time determining the note played, and bam, you've got a plucked string, yeah?

So a normal delay is probably going to be too long to be useful (although the first person to make a melody by using a normal delay module and modulating the *tempo* of the song gets a cookie,) but one of the quirks of a digital modular synthesizer is that it takes time to process all the modules.

The modules are processed left to right, top to bottom, so the only delay we can get is by placing the next module in the signal flow to the left of the previous module. Lucky for us that's a somewhat usable almost a quarter tone below an F.

All we can do is change the number of delays the signal goes through before it reaches the filter, so if that low C# sounds a little out of tune, that's because we're making notes on the SUBharmonic series, isn't that some shit? en.m.wikipedia.org/wiki/Undertone_series

The actual modules aren't anything special. A K35 LPF because it's the best at incremental filtering. The delaying modules can be anything, here they're just mixers. The faders on the top right mixer correspond to taps in the signal, the further right, the fewer delays it goes through.

This is a temperemental beast, try not to let it feedback too hard, or at least take off your headphones. You can actually use the decay env itself as the initial exciter, but I think it sounds better with the noise.

Stay classless.

P.S. As a bonus, a tuned bandpass filter on some white noise, because I didn't spend two hours tuning it for nothing.

SToons Music
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Joined: 03/01/2018 - 02:48
Woah! Bravo! The fact that

Woah! Bravo! The fact that you can lengthen the decay time (begs experimentation with a DADSR) and tweak the Res till it's about to explode is a major plus. Super cool and right up my sonic alley. Tuning it for different purposes (notes) may prove to be a bit of a challenge but thanks for sharing.

James
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Joined: 01/21/2013 - 07:09
Okay, I can tell it sounds

Okay, I can tell it sounds interesting and I've listened to it and it's an interesting sound but I'll be completely honest, I don't have a clue of the how / why.

Does the second modular do anything?

The first modular is a KS Synth built from the ground up, and the KS Synth is there as a comparison? There's no machine input on the first modular is there?

nitro27
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Joined: 10/11/2015 - 18:27
In reverse order:

In reverse order:
No machine input
There as comparison, yeah
Honestly I forgot it was in the file
Why: I noticed the effect while making a noise track and wanted to show it was possible
How: Something something comb filters I think

I couldn't find a way to make it play other notes, so it's probably not useful for, like, music and stuff, but tech demos are cool.

I make Chillout Electronic Music, and sometimes Ambient. http://floatingbeyond.tk
https://soundcloud.com/floatingbeyond

edgey
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Joined: 01/02/2014 - 10:19
Tuning it for different

Tuning it for different purposes (notes) may prove to be a bit of a challenge

Resample into the PCM.  Job done.  

paulovski
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Joined: 09/19/2012 - 06:13
First rule of modsynth. If it

First rule of modsynth. If it emanates from the end of a cable, it's a modulation source :)

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SToons Music
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Joined: 03/01/2018 - 02:48
Doh! (Insert pic of

Doh! (Insert pic of unlubricated gears grinding away).

SToons Music
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Joined: 03/01/2018 - 02:48
@paulovski - I imagine an MRI

@paulovski - I imagine an MRI of your brain would pretty much look like a ModSynth with 10 billion components.

After managing to digest one plate of spaghetti my own self interests noticed this ridiculously awesome coolness sitting quietly in the corner. While not a resonator I didn't know where to post it but wanted to highlight it.

I tried to dumb it down a bit for those of us that are Modularly Challenged.

Also thinking if one could combine and (fine) tune a resonator and the variable AM/RM they might be able to create textures like Storm Drums among other things.

Meanwhile, someone get this man a full room of Mods, he might inadvertently solve climate change.

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SToons Music
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Joined: 03/01/2018 - 02:48
Still trying to wrap my brain

Still trying to wrap my brain around the negative output...

Edit - ok, bit of an oddity but if I take the original HalfWave caustic file and set the top wgen for +2 octaves, lower the marked In2 to zero and raise the marked AM full then
- sometimes the lower osc is fully negative, sometimes positive...

Even if the lower Osc shows all negative values, if the file is saved and then reopened the waveform will now be either centered or fully positive but never negative. Odd indeed.

Trying to understand why it's not consistent. Maybe I need to figure out the "Sync" or something?

Hopefully someone can confirm this behaviour: if you load HalfWave2 and play, the lower Osc shows a positive wform. If you switch the Oct of the lower wgen to +1 the waveform centers. If you switch it back to +2 the waveform may be pos, neg or centered, seems to be a crapshoot.

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paulovski
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Joined: 09/19/2012 - 06:13
If I were let loose in such a

If I were let loose in such a room, the cloud of smoke I'd generate would, probably, blot the Sun out for several months.

I haven't had a chance to look at these anomalies. I will. But, hang on. The half wave rectification thing. That's not, quite, it. So, let's explain that, and why I'm doing it here. Resonators like short pulses from Decay envelopes to trigger. They like short pulses. The DC output of an LFO set to sawtooth is, very much, like the output of a string of retriggered Decay envelopes. But, at slow rates, that can be, quite a long pulse. And resonators like short pulses, even at faster rates.

Here's a WG, instead of an LFO, because it's a bit clearer on the scopes.

Scope 1. The AC output. Equivalent to the AC output of the Mini LFO.

Scope 2. The AC output, offset with positive DC. Equivalent to the DC output of the Mini LFO.

Scope 3. The AC output with positive half wave rectification. Only the positive half of the cycle gets through. During the negative stage, out comes a value of zero. And I'm trying to run a mod input with an LFO. I can't use the AC output. I don't want to ring mod that noise generator. I want it to shut up. And the sooner, the better. So, I have to use some kind of DC output. If I half wave rectify, I cut the pulse time in half. And resonators like short pulses.

A bit off topic, but whilst we're here. There's a, positive, DC signal running through the pan module here. If it were the equivalent negative voltage, the result would be the negative stage of the cycle. With an inverted polarity. But that can be dealt with. And there's room for two. Here is a picture of some houses. The left hand WG is the roof. The right hand WG is synced, so tune it up. Note CV is not connected. Feel free to plug it in.

Anyway. AM/RM. Yes, yes, yes. And this should be, pretty, easy to set up. When I first started mucking around with these, I had the feedback loop up too high. like the 'Too Much' example here. The scope is the only thing connected. If you play this for long enough, it will spin out of control. Eventually. And, with AM, that can translate as 'REALLY FUCKING LOUD'. Bare that in mind. But, until then, the mean voltage of those resonators is rocking, backwards and forwards, across zero. And, if they're modulating amplitude, the result is a drift between AM and RM. So I reckon that, careful, modulation of the feedback loop 'Depth' should sound really good. I haven't tried it yet :)

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paulovski
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Joined: 09/19/2012 - 06:13
The anomoly thing. It doesn't

The anomoly thing. It doesn't matter which oscillator you detune. When you put it back, you will have changed the phase relationship between those oscillators. And you're ring modulating. That would mess up polarity.

I'm more surprised that you see anything different when you reload the file, to be honest (not, necessarily, the way you left it). I'm not. They, generally, start to oscillate at the same phase position and frequency, the moment you 'activate' them (those long LFOs aren't, that, random).

It's not detrimental in any way, but synchronising would stabilise that phase relationship. If the modulator is the clock. Er. This is good. If the carrier is the clock, things get a bit wild. If you play with the phase (FM) of the modulator, wilder still.

Another kettle of worms :)

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SToons Music
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Joined: 03/01/2018 - 02:48
First off, ouch. Secondly,

First off, ouch. Secondly, yay! Initially I was pretty lost trying to follow the signal paths so it took me some time to catch up but it was well spent. I didn't have a clue what a 'rectifier' was either. Took a few days but eventually the bulb activated. The Houses thing was cool; trying to visually dissect it there's this 3 input mixer with only one input being used...WTF??? Of course once bypassed by connecting the BP directly to the pan module it was clear. So, thanks for the explanations, and I was never gonna follow the rest without taking some time to break everything down for myself. Will post some of the stuff I threw together later when I have time to write proper notes.

Anyways, for others like me struggling to keep up here's some rectifiers, a Full Wave Rectifier and a Half Wave Rectifier based on the same concept, slightly different than paulovski's HWR. The top WG for the FWR is for illustration purposes only. Press Play for the scopes to be happy.

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SToons Music
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Joined: 03/01/2018 - 02:48
Just to add something

Just to add something contextual...

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paulovski
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Joined: 09/19/2012 - 06:13
Hang on. The ones in

Hang on. The ones in 'rectifiers' are DC offsets. Rectification implies that you get rid of one polarity of the waveform, or the other. You need the panning module for that.

Edit. Half wave rectification

SToons Music
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Joined: 03/01/2018 - 02:48
Damn, trying to learn to

Damn, trying to learn too quick again. Ok, so I'm guessing what I posted are not true rectifiers and just mimic them in the confines of the WG. Think I get it. What they produce with simple waveforms looks like the diagrams on Wiki using sine waves, but, if you plug in an say a machine input they wouldn't work.

With the pan module it seems to.

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paulovski
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Joined: 09/19/2012 - 06:13
OK. You have HWRd  that

OK. You have HWRd  that subsynth, and isolated the positive stage of i it's cycle.

For the negative stage. Invert the subsynth polarity before modulating the pan module. And send a negative DC voltage through the pan module .

Then mix the outputs to get back where you started. Two different, synced oscillators are a bit more fun.

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SToons Music
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Joined: 03/01/2018 - 02:48
Here's my lack of

Here's my lack of understanding: what I read about full wave rectification implies everything that is positive stays that way, the parts of a wave that have negative polarity are inverted.

So if I take this example you posted, switch to a sine, at no point do I see a fully rectified wave like this:

https://i1.wp.com/upload.wikimedia.org/wikipedia/commons/9/9f/Rectified_...

What am I missing?

The way it appears is that the positive and negative polarity are each half rectified, but, the half rectified negative wave is inverted to positive before being mixed back into the half rectified pos. The fully rectified wave in the end is completely positive and doesn't look like the original.

Other odd anomalies: why is the saw wave coming from the SubSynth inverted?

Anyways I realized a rookie mistake - after getting super frustrated, for hours, that the waves you inverted didn't look inverted (and that you're usually right in the end so what the fuck was I missing...) it dawned on me that maybe I just wasn't looking at things the right way and I flicked the Trig off. Argh!

So for my own visual understanding, and the benefit of other novices who may read) I modified your Neg example. With the Triggers disengaged you can clearly see the lower one is inverted but when it's engaged... well, you know, it doesn't look inverted! Now I feel pretty dumb. And I've wasted more than a few hours wondering why the osc told me I was wrong about something I was working on when it turns out I didn't know how to use it properly. And generally under most circumstances waves fly by way too fast to visually see them. Oh well, at least I kinda know now.

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paulovski
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Joined: 09/19/2012 - 06:13
Ah. I'm not trying to FWR

Ah. I'm not trying to FWR anything. I'm isolating + of one wave and - of another to recombine two different wave shapes in one +/-  cycle.

If, during that negative stage, you were to run a positive signal through the pan module, the result would be FWR.

But you'r FWR in 'Rectifiers' is doing that. It would be better if you removed that mod input and dropped the octave of the sine.

Because swap the square with a pulse that can be modulated.. With it's output modulating FM of the sine. And give the sine output a bit of negative bias. You'll be needing it.

But, this doesn't have much to do with resonators and a lot to do with wave folding.

Let's go there :)

That's what the subsynth does.

UncleAfx
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Joined: 03/06/2016 - 20:08
Awesome to see new ground

Awesome to see new ground still being broken with the modular. It's still a lot like magic to me, but I keep thinking some day I'll try and make sense of it...
With all the attention the modular has been getting, it's too bad it all
can't be organized into it's own subforum.
As for the rectifiers, obviously there's a use for rectifying, but I still haven't figured it out. Other than just "because you can". But then again, maybe that thinking is partly why I'll never get it....

SToons Music
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Joined: 03/01/2018 - 02:48
@UncleAfx think you nailed it

@UncleAfx think you nailed it. I have yet to find a productive musical use for rectification (just discovered what it was beyond a term used in my beloved tube amps) but I can assure you - I will! I have ideas but only time will tell.

And really the only thing that lead me down this path was curiosity, the "because I have to" (a little OCD there) forces me to learn new things and I really want to get a better grip on the polarity and VC stuff, it's very helpful to understanding sound design and keeps my brain from total atrophy.

Another benefit is often while "attempting" to build something like a rectifier I accidentally connect a cable and boom - what the hell was that? Dunno but I like it... the accidental discovery that you can claim you intended and engineered lol.

And last but not least the more I learn the easier it is to have or develop some rapport with others which for me is also important towards personal growth. I'm not always motivated and creating 'fake' goals is my mind trick towards motivation. That and weed. I gave up on music getting me the hot girls long ago.

UncleAfx
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Joined: 03/06/2016 - 20:08
Yeah I think that's what it's

Yeah I think that's what it's really all about... the accidental discoveries. A rectifier might not be much by itself, but maybe it's just one or two steps away from something completely cool and impossible without it.
Funny enough, I accidentally discovered rectifiers by manually doing it in the pcmsynth. I only found out it was a thing when I started searching splitting positive and negative to see what the uses might be.
That's why I love this sort of stuff though, it's in the spirit of experimentation and discovery. :)

paulovski
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Joined: 09/19/2012 - 06:13
Have you, ever, found a use

Have you, ever, found a use for the foldback setting of the distortion insert? 

Wave folding. You'll find plenty of uses for it there.  I'll post something in that topic soon.

SToons Music
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Joined: 03/01/2018 - 02:48
Wavefolding? Not yet but

Wavefolding? Not yet but intrigued. Was following your previous post though and hope to look at it tonight. You've dumped enough on the table the past two weeks to keep me going for a while. The closest I've come to it so far was to use DC offset to morph between RM and AM which is a cool concept but obviously not the same thing so I'm all into discovering some potential self-serving implications. I unapologetically confess to being musically selfish - how can I put shit to use?

I've used the Foldback on occasion and used Foldback distortion for years in guitar pedals so I'm intrigued cause I love harmonic variation.

Thanks for all the help. I feel like a cook learning to use new found exotic spices. Should tonight be Thai or Indian?

SToons Music
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Joined: 03/01/2018 - 02:48
https://youtu.be/fZ1rviedGvc

https://youtu.be/fZ1rviedGvc

She's so cool.

And just for fun here's a KS inspired non-sanctioned Walmart version.

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