From the course: Demystifying Audio Synthesis: Beyond The Basics

Inside modular component synthesis - Logic Pro Tutorial

From the course: Demystifying Audio Synthesis: Beyond The Basics

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Inside modular component synthesis

- [Instructor] As we get into programming more complex synthesizers like logic's alchemy, or native instruments massive. The first thing to identify is that all the usual suspects are still around such as oscillators, envelopes, LFOs, and filters. There's just simply more of them and more importantly, a larger amount of flexibility in terms of how they can be routed to and from each other. Speaking of routing, I want to start out here by introducing you to a classic old school synthesizer the ARP 2,600, which is a emulation here by Arturia. Now, the reason I want to start here is because the ARP 2,600 has all of these usual suspects. It has oscillators here known as VCOs, voltage controlled oscillators, it has envelopes, as we can see here with the ADSR envelope generator and it has LFOs as well. Now, by starting here and learning how we can patch these oscillators into envelopes, into LFOs, we can begin to understand what a modular synthesis workflow looks like and we'll do that before we move on to the more complex since like massive or alchemy. So, this is the classic modular style synthesizer in the ARP 2,600. This instrument came out in the early 1970s. The instrument took the basic building blocks of analog modular subtractive synthesis and put it in a compact suitcase. You've heard this synth in music from the 1970s and also famously, it was used by sound designer, Ben Burt to help make the voice of the famous droid R2D2 in Star Wars. Now, as usual, it all starts with the basic oscillators. On the app, we have three, VCO 1, VCO 2, and VC O3. The V here stands for voltage and voltage controlled oscillator. Now back before we had middy control, we had something called control voltage to turn the state of an oscillator on and off and control its pitch. Nowadays, I have my mini keyboard connected to this instrument to control node on and off messages and pitch, but we still use the VCO in the terminology to keep true to the classic nature of this synth. So let's say I wanted to make VCO 1 spit out a square wave or a Sawtooth wave. You can see it has two outputs. One's for square, one's for Sawtooth. I would want to take the output of let's say the square wave and connect it to something called the VCA over here. And I'll plug it in. These are my VCA inputs. I'll plug it into channel one. Now VCA stands for voltage controlled amplifier. So it's able to amplify our oscillator so that we can hear it. Now notice we have some terminology in white boxes down here. That's indicating what's normally patched without connecting a cable like I did here. So normally the VCF, something called the VCF which we'll talk about in a second is patched into channel one. But I broke that connection by hard patching a cable out of the square wave into channel one. Now, as long as this has turned up, I can play my mini keyboard and we'll hear a square wave. Sounds like this (upbeat music) So we've got our square wave going into channel one. Now this doesn't give me very much control. For example, I can't change the filter frequency or a cutoff filter on this VCO because I'm not connected to a filter yet, but we might as well do that. And that's where the VCF comes in. So I'm going to go ahead and disconnect, to say remove connection I'll right click, Remove Connection, and I'll connect the square wave into our VCF and I'll choose one of these available inputs. I'll make sure that's turned up all the way. Now, I can change the filter frequency and it's set to low pass filter right now LP 24 and we can hear that filter acting on my square wave. (upbeat music) So you hear the high frequencies are being removed when I changed the filter. So, now I've got a bit more control of my oscillator since it's going to the filter and why are we hearing it? Well, that's because VCF is automatically patched to the input of our VCA. Remember I don't need to make a patch because it's normalled according to what it says here, VCF is automatically connected there. So that's how we can connect a filter. Let's go ahead and connect another oscillator. So we'll use VCO 2. And in this case, we'll choose these Sawtooth output. So we'll connect that also to our VCF. So now if I turn this up, we've got two oscillators in unison going into the voltage control filter. (upbeat music) I also have a sound is about fatter. We've got two oscillators driving that. Next, what if he wanted to control how the VCF opens up over time? If you remember from the synth basics course, you can control the timing of different synth functions with an VCR envelope generator. And it just so happens we have one right here. So let's connect the output of the ADSR generator, the ADSR envelope into our VCF. And we've got a slot for it right here under control. Now, as long as this has turned up, I can change for example the attack time and have this filter, I'll turn it down a little bit so we can really hear it, have this filter open up slower or faster over time. So right now it's set all the way fast. But if I change this to be a little slower, you'll hear it open up (upbeat music) over a certain amount of time. I can go even slower than that. (upbeat music) Now the filters slowly opening up according to my attack time. In this case it's set to 781.25 milliseconds. So almost a second. Put that filter to open up over time. Finally, what if we want him to control the way that this ADSR envelope opens up in an oscillator in other words, going on and off. If you remember also from the synth basics course, we can attach a low frequency oscillator to any parameter to make it kind of follow a sine wave of on and off. So to do this, I can use VCO 3. Notice that all three VCOs have a setting for LF that stands for low frequency. So, any of these three oscillators can be used as a low frequency oscillator or LFO. So I'm going to go ahead and make sure this is set to low frequency on VCO 3 and I'm going to take these sine wave output only instead of making this go into our voltage control filter or VCA I'm going to actually connect it to the ADSR. So now this LFO it's controlling how the ADSR or how the envelope opens up our filter. So when I hit a note we should hear the ADSR opening up according to the frequency of this low frequency oscillator. (upbeat music) Now you hear it opening and closing and I can of course change this frequency to be faster or slower. (upbeat music) So, we now we've got a basic sound. We've connected, two oscillators to a filter and the filter is being controlled by an LFO. So now that we've seen how flexible a true old school modular synth, like the ARP 2,600 can be, I'm going to stop there. And in the next movie I'll shift over to logic's alchemy instrument so I can show you how this kind of modular flexibility that we've seen here has been written into a more modern synth, of course with some added bonuses.

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