Post by NightMachines on Jul 12, 2020 14:05:26 GMT
I've done a little bit of research on envelope generation* in the past couple of months and wanted to show you what you can do to better control and spice up the envelope applications in your AE Modular systems.
A short foreword:
Envelopes have been an often neglected part of synthesizers. Most of them just have one way of rising and falling and that's it. However, they never work alone, but instead require a target for their modulation CV to have an effect in our patch. Typically those targets are VCAs or Filter cutoff inputs. The problem that arises frequently then, is that those VCAs and Filters have a certain fixed response curve as well. So a VCA that receives a linear decay envelope might not actually lower the volume of its audio linearly. It's all analog after all and there are nonlinearities all over the place. So what can happen is that a certain envelope and a certain VCA or filter may not get you the sound you want, because both of their fixed characteristics just don't sound "good" together. An example most of us probably know is the "snappiness" of a percussion or bass sound. Sometimes there is a lot of this "snap" and sometimes there isn't. People tend to blame the envelope then, but it's actually the interplay between the envelope and its modulation target.
So what can we do? Responses of VCAs and Filters are often not adjustable and if they are, it's usually just something like a switch between two fixed responses. Luckily though, we can modulate the stages of our 2ENV and ADSR modules in our AE Modular synths!
Let's look at a normal ADSR signal first though:
Ah, here we already see something we might not have expected! Attack, Decay and Release are not a linear! They're somewhat logarithmic.
Let's look at a normal 2ENV attack decay signal:
Same as above, also not linear. This is a typical occurrence on the majority of analog envelopes, as the CV is generated by charging and discharging a capacitor (basically a tiny rechargeable battery). This capacitor does not charge linearly obviously, but it's a simple circuit and thus the module can be made to a very affordable price. It also usually sounds okay when modulating something.
So how to shape those curves now? We need modulation, of course!
Here's the 2ENV from above again, with just one patch cable added. It's an old and simple envelope feedback trick:
By feeding the output of the envelope back into a modulation input (decay mod in this case), we shape the curve in real time while it is forming.
I'm sure you can imagine what comes next
----
* you need a Muffwiggler account to see the pictures there unfortunately
A short foreword:
Envelopes have been an often neglected part of synthesizers. Most of them just have one way of rising and falling and that's it. However, they never work alone, but instead require a target for their modulation CV to have an effect in our patch. Typically those targets are VCAs or Filter cutoff inputs. The problem that arises frequently then, is that those VCAs and Filters have a certain fixed response curve as well. So a VCA that receives a linear decay envelope might not actually lower the volume of its audio linearly. It's all analog after all and there are nonlinearities all over the place. So what can happen is that a certain envelope and a certain VCA or filter may not get you the sound you want, because both of their fixed characteristics just don't sound "good" together. An example most of us probably know is the "snappiness" of a percussion or bass sound. Sometimes there is a lot of this "snap" and sometimes there isn't. People tend to blame the envelope then, but it's actually the interplay between the envelope and its modulation target.
So what can we do? Responses of VCAs and Filters are often not adjustable and if they are, it's usually just something like a switch between two fixed responses. Luckily though, we can modulate the stages of our 2ENV and ADSR modules in our AE Modular synths!
Let's look at a normal ADSR signal first though:
Ah, here we already see something we might not have expected! Attack, Decay and Release are not a linear! They're somewhat logarithmic.
Let's look at a normal 2ENV attack decay signal:
Same as above, also not linear. This is a typical occurrence on the majority of analog envelopes, as the CV is generated by charging and discharging a capacitor (basically a tiny rechargeable battery). This capacitor does not charge linearly obviously, but it's a simple circuit and thus the module can be made to a very affordable price. It also usually sounds okay when modulating something.
So how to shape those curves now? We need modulation, of course!
Here's the 2ENV from above again, with just one patch cable added. It's an old and simple envelope feedback trick:
By feeding the output of the envelope back into a modulation input (decay mod in this case), we shape the curve in real time while it is forming.
I'm sure you can imagine what comes next
----
* you need a Muffwiggler account to see the pictures there unfortunately
