Synth Tutorial: How to use the Serum LFO’s Envelope mode and Loopback point to create an LFEnvelope


Watch Joe Hanley, the creator of Syntorial, as he demonstrates the Serum LFO’s Envelope Mode and Loopback Point. In this excerpt from the Serum Lesson Pack learn how to use these together to get a hybrid LFO and Envelope, AKA LFEnvelope.

Get 4 more Serum videos for free via the Syntorial Demo.



In this video, I’m gonna show you how the LFO Envelope Mode and Loopbacks work. When we use these together, we can create a hybrid LFO Envelope, or as I like to call it, LFEnvelope. Now this video is actually an excerpt from the Serum Lesson Pack for Syntorial.

Syntorial is a synthesizer training app that teaches you how to program synth patches by ear. It does this by combining video demonstrations with interactive challenges in which you program patches on a built-in soft synth. The Serum Lesson Pack adds 55 videos that show you how to take everything you learn in Syntorial, and apply it to Serum.

As well as covering all the many additional features that Serum has to offer. And you can get the first four videos from the Serum Lesson Pack for free by going to, clicking Try For Free, and downloading the Syntorial demo for Mac, PC, or iPad. This has the first 22 Syntorial lessons, but also the first four videos from the Serum Lesson Pack. Once you download Syntorial, just go into this dropdown, download lesson packs, and you’ll see the Serum Lesson Pack at the top. Just click the download button. We also have Lesson Packs for Massive, Sylenth, and a couple others.

And like I said, the demo will have the first four or five videos from each of these packs. When you buy Syntorial, all of the packs, and all of their videos, are included. All right, onto the excerpt.

Envelope mode runs through our LFO only one time. Goes from here to here, and then stops at this value. So it essentially turns it into an envelope, right? ‘Cause our envelope only executes one time. And so what this allows us to do is create really unique envelope shapes. You know, over the envelope, we’re stuck with what they give us, a standard ADSR with a hold. Over here, we can do anything we want. So let’s look at some examples.

So this LFO is assigned to this sync warp On normal, you hear how it goes “Yip”? To this value, but it’s only there for a split second. And then it starts over. It’s just repeating, repeating it. But an envelope, it hangs out there. Another example So this LFO is routed to our volume. And what we get is this LFO creating this and then swell up. And then our regular amp envelope keeps our volume at the top for a while to allow this to be heard, and then fades eventually.

So you get two amp envelopes, essentially. You get one with the unique shape, and one with the standard, just, kind of hold gate shape. Now, within this envelope there’s a couple features. We’ve got loopback points. So, I’ll route you to you. Okay, so let’s go envelope mode. All right, so just, one time through. But if I set a loopback point on this note here. You see a little “L” pops up now, Ah, so it executes the whole LFO once, and then it repeats from the loopback point. I can put that on a different note, and now it’ll loop back from here. I can move it. So effectively we get an LFO and an envelope in one.

Great example of this in use… So this LFO is largely in this wavetable position. And I can almost guarantee that this was an actual sample, like a bottle blow, like a “Hoo” when you blow over the top of a glass bottle. Imported it, because the first part of this wave table is the attack. When you pass over this area quickly, it’s that , it’s that initial blow. The attack transient of the bottle blow. Then this is all the body.

Now… What we get here is this quick sweep, Alright this “shoom” That gives us that attack transient. And then we move up and down and we loop through this. Okay what’s the point of the loop? Let’s remove it. See it’s the movement of this wave table. Oh! Sorry. So when you move it that’s when you get that kind of airy sound.

So movement’s really important for the sustain of this. But, with a regular LFO, we’d hear this attack. Over and over again. So, perfect solution. We hear the attack once ’cause we’re in Envelope Mode, and then we loop back just for the body. We can apply this same principle…

To see the rest of this video, and 54 other Serum videos, you’ll need the Serum lesson pack for Syntorial. But again, you can get the first for videos for free if you download the Syntorial demo here, and then in Syntorial, go to download lesson packs. And, download the Serum lesson.