filter envelope attack

Easy Synth Programming – Filter Envelope Pt 1

Easy Synth Programming – Filter Envelope Pt 1

You want to have interesting sounds. Ones that go ‘wwerrr’ and ‘psheww’ but yours just sit there and go ‘duhhhhh’. It embarrasses you to play your patches for people because they sound too juvenile. Well what if I told you that you can use the synth like an interest-generating robot to suit your every whim? I do have such a solution and it’s called the filter envelope attack and release.

No Motion in the Ocean

After you’ve unpacked that new hardware synth or downloaded that new copy of Serum, you expect to be the next big thing. Come on, we’ve all had that feeling. Yes – I will be the great white , brown, 20180210black or yellow hope. Everyone will bow down before my synth greatness. Yes, you can come back to reality and realize that you’ve goofed up the installation. Maybe your next step will be to check out the presets or god hopes not some sample packs you can download to make your choices even more multitudinous. This would be a serious mistake my man.

Everyone has to start somewhere and using presets is a great start. They allow you to see what a synth can do as well as getting useful sounds right from the start. Some producers just use presets all the time – even without any tweaks. The funniest part is when someone can recreate a whole dance hit just using presets. Whether this is art or not is a different story.

The downside of using presets is that everyone has them. If you want to stand out then how can you do so when you sound like everyone else? It’s not like this is blogging we’re talking about here where no one hears your voice. This is music and you can’t tell me that the Doobie Brothers sound like Bjork. They use totally different sounds.

Think Different

Even if you imagine an electric guitar, you never hear it playing just a solid static sound. You imagine Hendrix playing some chunky chords before he rips into another stratospheric solo. This is definitely the antithesis of boring. If you want to charm the panties off your date then being boring is not an asset.

While there’s no problem with using presets the thing is that eventually you’ll want to know how to make your own sounds. However, whatever you try to do this it sounds like you just graduated fifth grade and have never played a keyboard before in your life. Welcome to synth adolescence where everything is awkward and nobody understands you. Understanding your situation is half the battle.

You just need to understand that the reason your sounds are lacking any interest is because they have no motion. Just like a great singer, movie, or sculptor, you need to learn how to take your audience by the hand and lead them where you want to go. You can easily just point them in a direction too – no need to be explicit. Unfortunately, if you can’t hold their attention, you won’t have an audience. You need to get moving.

Through the Looking Glass

Motion in your sounds can be caused by many things. We’ve already discussed the amp envelope and how that changes the volume of your sound over time. The thing is that songs are interesting because they’re not the same 8 bar loop playing for four and a half minutes. The intro might be soft and inviting while the bridge is a floor stomping chest thumper while it passes into a military march. That sounds like something interesting to hear. In contrast, if all that happens once you press a key down is a square wave gets a little louder for awhile, you’ve not going to be having any successful concerts.

While an amp envelope is like a window shutter opening, other types of modulation are akin to what you see when looking through the glass. These revealed landscapes can be lush, jagged, all sky or the very face of hell. Exactly how you come to these various images is through movement. At the very least there needs to be some contrast. I like to use deadmau5 as an example when discussing filter envelope attack. He uses pluck sounds a lot and that can get boring. How does he keep it interesting?

Parallel Motion

Have you noticed that he has sections where everything is plucky and dark but slowly he raises up the filter to make everything sound brighter? This is very similar to a guitarist doing some single-string palm muting then opening up to power chords with a wide open tone knob. Yep, that tone knob on your guitar is actually just a low pass filter. Normally, we don’t use it much when we’re playing because we’re busy with chords n stuff.

Maybe a more realistic example will help you. Imagine your outside by a road that’s extending away from you and has tall buildings on each side. A motorcycle going down that street will slowly become more distant sounding. You already know that but have you broken down the components which make it sound that way? Reverb, frequency filtering, and time delay all play a factor.

Just like guitar players, synth people can also get their hands full. But think of a Moog Voyager. This synth only plays one note at a time. I mean, you can wave to the hotties in the audience with your other nine or so digits but isn’t there a better use? This is going to sound an awful lot like the Matrix but what if I told you there’s a better way than doing it yourself?

I, Robot

By now, we know that the solution is to add motion. In many synths, just about everything can add motion to a sound. The problem with that is our number of fingers and feet. Luckily, synthesizers have little automation functions called envelopes and low frequency oscillators (LFOs for short). Today we’re going to focus just on the filter envelope and even then only two parts of it: filter envelope attack and release.

We already have covered the filter so we should know what it does. To do a brief recap, a low pass filter removes high frequencies from your sound. When you turn the knob while playing, you can hear a manual modulation. The cool thing about automating it, though, is that you can make those filter sweeps fast, slow, and perfectly smooth.

Let’s take a hypothetical example of a static sound playing a saw wave:

The amp envelope in this example is just zero attack, full sustain, and zero release. It’s basically an on off switch. So what will it sound like if I manually move the filter cutoff knob around manually?

Here, you can hear that I’ve wobbled the filter (just like an lfo) but have also tried to make sharp cutting sounds similar to a pluck as well as long sweeping sounds. Now it’s time to compare what it sounds like when massive does these things using an automated set of modulators.

You can easily tell how the filter envelope attack is much sharper and more precise than my own. Since you can set the filter envelope attack to milliseconds or sync it to your song, you can be sure it’s perfectly repeatable too.

How Much?

Now that you can hear for yourself what filter envelope modulation can do for you, there’s just one more thing. I lied. There’s actually one more part we need to discuss. That is how much of the filter envelope attack and release will be applied to the sound. You see, it’s all well and good to have the filter envelope changing the filter’s value automatically. But what if we want it to have more or less of an effect?

In that case, we’ll use the amount knob in Primer or use Massive‘s automation functions to increase the magnitude of effect. First we need to make sure we have a good understanding of what that sounds like. Listen to these two examples. Example is the same as before but example two is everything the same but with the addition of more amount of modulation:

Do you hear how it sounds like the the filter envelope attack goes higher? That’s the point of this function. In this way, you can have subtle filter movement all the way up to very drastic. Once you later learn about filter resonance, this mechanism will allow you to make really cool zap noises.

I’ve Heard This Before

The fundamental way that the filter envelope works is just like the amp envelope. There is one main difference. With the amp envelope, you essentially fade up your sound from nothing. The filter envelope is different because you can create an offset with the filter cutoff knob. Instead of your filter sweeping up from 0 Hz, or wherever is it’s lowest point, you can start the filter envelope attack from anywhere on the dial.

The caveat to this is that if you have your filter opened up a lot already, then applying maximum amount values to your filter envelope attack and release won’t do you much good. The modulation signal will clip and, while the envelope will continue to pump out data, your knob can only go so high so no effect will be heard. In addition to this, filter envelope attack and release (movement) is really hard to hear up in the highest frequency ranges.

On a side note, there are some synths which allow for a similar offset in their amp envelope. I know that the Operator synth inside of Ableton Live is one of them. This, however, is not a traditional approach. Operator is based on additive architecture whereas what we’re learning in Syntorial is based on old school subtractive synthesis like that of the early Moog products. As far as I know, the historical hardware just had a standard ADSR option for it’s modulating envelopes.

Nitty Gritty

By now you know that there are several modulators you can use including LFOs, sequencers and perhaps others. Here we’re focused on the filter envelope’s attack and release which are just two parts of your regular Attack, Decay, Sustain, Release or ADSR envelope. At this point, I want to show you how to specifically implement these two values into your sound making. I’m going to use both Primer and Massive to illustrate the point.

Let’s start with Primer. This is the VST that comes included with Syntorial and functions as both a plugin in addition to being the interface for learning. The main difference is that, in the demonstration,s the parameter values are limited since it would be virtually impossible to get the precise answers if the knobs were totally continuous as they typically are in virtual instruments. Go ahead and instantiate primer and initialize the patch.

In contrast to Massive, the filter envelope is pre-assigned and always available. This is convenient especially if you’re just starting out but also to get sounds quickly. Set the filter cutoff to around half way and turn the filter envelope attack and release to zero ms. You’ll probably hear no change at this point. This is because you need to turn up the envelope amount knob up to soft of “open up the gates” to the filter envelope. After you do so, you’ll hear that your sound is just brighter. But that’s not what we want.

Blindingly Fast

The sound just got brighter because you have your attack at zero milliseconds. Do you nkow how fast that is? it’s instantaneous! Something happening immediately and something never happening both share the dubious honor of virtually not happening at all. At least for our ears, we need something more than 10ms to perceive it as motion. So, with that in mind and keeping your envelope amount knob half way up, turn up the attack time slider until you start to hear a ‘woosh’. Low values will do this but lets stick with 1000ms for now which is 1 second.

At this point you have a sound in which the filter opens over the course of 1 second. The filter envelope starts where your cutoff knob is, like we’ve previously discussed, and goes “up” by the amount set by the amount knob. If you turn the cutoff down, then you still get filter movement but the whole motion is offset but that much. Play around with these two values to see what happens.

The last thing you’ll need to master this lesson is the release value. Just as in the amp envelope, the filter can do something after you’ve released a key. In our case, it’s just shutting down like a bank on Sunday (thanks, Mike Patton, for that). If you want it to ease you away like a girl that’s curving somebody, then increase the slider also to around 1000ms. Now, assuming you have your amp release set long enough so you can hear it, you’ll will hear the filter slowly going back into it’s resting place. Ah, the cycle of life.

The Other Man

If you want to perform this task in Massive then it’s very similar. The main difference is that you have to assign one of the available envelopes to control the filter cutoff. in the center window you can see blue cross hatches for each of the four available envelopes. By default, the fourth envelope is assigned to the amp envelope. For now, why don’t we assign that one to the filter cutoff as well.

You’ll notice that there is no amount knob in massive. instead, what they’ve done is allowed you to click and drag in the assignment window so that a blue line appears around the circumference of your target knob. This is how you control how much the envelope affects your sound. Once you’ve achieved a basic envelope assignment and given it an amount value, play with envelope four by increasing the attack and release times.

One advantage of using the same envelope for both your filter and amp is that your filter envelope attack and release will match the overall curve of your sound. This is nice because sometimes you want this. Doing it this way will also help you from getting confused this early in the game. if you feel like you’ve mastered assigning an envelope, adjusting the attack and release, as well as determining an amount for the attack and release to work, you can assign another envelope. This way, your filter envelope attack and release will be independent, though still related to, your amp envelope.

Futuristic Values

While all this might seem very beginner-like now, mastering the basics of automated modulation will pay dividends in the future when assigning modulators to other parameters – synth functions like pitch, fx amount etc. This is where your sound design will really start to shine. However, learning the basics of synthing is no different than any other skill-based learning, like math. Everything you learn here will build upon itself later.

If you don’t know how to assign an envelope, or how to set your filter envelope attack and release then how will you ever manage to apply modulation to advanced concepts like multiple envelopes for FM operators, pitch envelopes, and automated effects – especially when they’re all happening in the same patch? Again, like math, things will get extremely confusing if you don’t have a firm grasp of every individual component. Still, there’s one even better way to gather this foundation.

Merely intellectually knowing what the knobs do, or even having a mathematical understanding, is not enough. Despite the exhortation to be able to explain everything in terms of numbers, the best way to understand music is by mental sound imprints. While it’s very important to understand the mechanics of a synths various functions including it’s filter envelope attack, release, amp envelope, oscillators and more, it’s far more important to know how everything sounds.

Get it Together

I haven’t found a better way of achieving that than Syntorial. Syntorial is video game-like training software which makes you figure out synth patches by ear. The difference from doing it on your own and using this program, though, is that your options are somewhat limited. While not exactly quite like training wheels on a bicycle – in fact Syntorial goes pretty far – it simplifies your transition into the world of synths. Simultaneously teaching you synth parameters and functions, training your ear, as well as creating an organized learning environment complete with homework assignments, there is no better way to learn how to make cool noises than this program.

I really encourage you to check it out. It has a free trial which includes 22 lessons, is cross platform, and even runs on an iPad. There are many more things you can be doing with your time besides wasting it on Instagram. Trust me, I know. Synths are such an efficient way of composing that I don’t know where I’d be without them. once again, the main problem with synths is that they aren’t very intuitive. Actually, they can be downright intimidating what with the wall of knobs, cables, and no sound coming out if your filter is all the way down.


Thank you guys for reading this article. I’m trying to make my posts more helpful by providing audio examples, better text instructions, and overall more content to make sure you never have to go anywhere else to the the important information you need. If you have any questions, feel free to leave a comment and be sure to sign up for my newsletter to get updates in your inbox. Thanks for reading and I’ll see you next week. Peace!

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