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Tutorial:
Serum 2 LFO Arpeggiator Guide

Author: VIRTUAL LIGHT

NOVEMBER 25, 2025

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Serum 2 can do a lot—but one of its coolest super powers is turning the LFO section into a full-blown arpeggiator. In this guide, we’re getting properly nerdy: the exact workflows, hidden functions, and sequencing tricks that let you build complex arps directly in Serum’s modulation engine. 

Back in Serum 1, there was no dedicated arpeggiator. Producers discovered a workaround: by using an LFO mapped to pitch. This setup let you build step-sequenced arpeggios entirely inside Serum 1. With Serum 2, Xfer introduced a proper arpeggiator — but the older LFO trick still works, and it’s a powerful tool in your sound-design toolkit. These two approaches have very different feels and use cases, and learning both will give your productions maximum creative flexibility. 

Title

The biggest reason to use the LFO method is freedom. With the traditional arp, all oscillators follow the same pattern. But with LFO-arping, each oscillator can run its own melody because you’re modulating pitch independently per oscillator.”

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Arpeggiator VS LFO Arp Explained

Before diving into the technique, it’s important to understand why you would use Serum’s built-in Arpeggiator versus using an LFO as an arpeggiator (the “LFO-arp” method). Both approaches have advantages, but they behave very differently under the hood.

 

 

Why Use the LFO-Arp Method

 

1. Independent Arps Per Oscillator (Layered / Multitimbral Trick)
The biggest reason to use the LFO method is freedom. With the traditional arp, all oscillators follow the same pattern. But with LFO-arping, each oscillator can run its own melody because you’re modulating pitch independently per oscillator.

 

This lets you:

  • Create layered riffs inside one preset
  • Make complex, multi-part sequences
  • Emulate multitimbral synth behavior inside a single Serum instance

 

2. Custom Glides & Micro Pitch Motion
Because the LFO is modulating pitch directly, not triggering new MIDI notes, you can draw:

  • Custom pitch slides
  • Microbends
  • Chirps, snaps, ramps
  • Bends between notes that no MIDI Glide can replicate

 

Traditional Glide always uses the same curve. LFO Pitch Mod gives you whatever curve you draw.

 

3. Creative Flow / Shape Browsing in Serum 2
Sometimes you do it because it’s fun. Serum 2 introduced LFO shape scrolling — you can flip through LFO presets instantly using the small arrows on the LFO shape selector. In Serum 1, you had to open the menu each time, which was slow.

 

Hack: Importing Serum 1 LFO Shapes into Serum 2
Serum 1 LFO shapes cannot be opened directly in Serum 2, but here’s a workaround:

  • Open the Serum 1 preset that contains the LFO you want.
  • Load the entire .fxp preset file into Serum 2.
  • Re-save that LFO shape as a Serum 2 LFO preset.
  • Done — Serum 1 shapes converted.
 Serum2 LFO Scrolling Through LFO Shape

Drag LFO to modulate pitch

Now, Let’s Set Up the LFO Shape Arp

The first step to setting up the arp is to assign an LFO to modulate pitch. There are basically three main options for how you can do this:

 

Oscillator Course
This option gives you the full range of pitches, including in-between notes, which allows for bends and glides. It’s generally the best choice when you’re working with a single oscillator and want full pitch flexibility.

 

Oscillator Semi-Tone
Modulates pitch in semitone steps, giving you precise 12-note divisions per octave. You lose the fine pitch control, but it’s ideal for strict melodic patterns or harmonically locked sequences.

 

Main Tuning
Works like Oscillator Course in giving full pitch control, but modulates all oscillators simultaneously, including the Sub. If you don’t need independent oscillator modulation, this is often the easiest and most convenient option. This must be assigned via the modulation matrix.

Drag LFO to modulate pitch

Setting Your Modulation Range

 

The next step is to set your modulation range. Fortunately, in Serum 2, the default range when you drag an LFO onto Coarse Pitch is a perfect 24 semitones. (This was not the case in Serum 1.)

Serum 1 - Double Click for Typable Values on Controls

Serum 1 - Type 24st for 24 semitone pitch range

Setting 24 Semitones in Serum 1

 

If you’re working in the original Serum, you must:

  • Enable “Double-Click for Typable Values on Controls” in Preferences.
     
  • Go to the Modulation Matrix, double-click the slot that your LFO is assigned to, and manually type “24st”.

 

This part was always confusing because even after typing 24st, Serum 1 would still display “19” — meaning 19% depth, which equaled 24 semitones. Not exactly intuitive.

 

Serum 2 Fixes This

Serum 2 now shows modulation depth in actual pitch values (st) instead of percentages. 

This makes setting ranges much clearer and far less hacky.

Bipolar vs Unipolar Pitch Modulation:

BiPolar Modulation

UniPolar Modulation

By default, modulation in Serum is bipolar, meaning:

 

The middle of your LFO shape = your root note (the MIDI note you’re playing)

The top half of the modulation range = +12 semitones

The bottom half of the modulation range = −12 semitones

 

This is a great general-purpose setup and the standard for most of my LFO arp shapes.

24 Semitones: +12 to -12 with 0 = Root Note

Alternative Modulation Ranges
 

However, there are a few different ways you can configure the range depending on the style of arp you want.

 

1. 24 Semitones / Unipolar (Upward Only)

This setup gives you +24 semitones above the root with no downward motion.

 

Useful for:

Rising sequences

Avoiding octave drops

 

24 Semitones / Unipolar (Downward Only)

Same concept, reversed.
You get −24 semitones only, perfect for downward-running riffs or dark falling sequences.

Unipolar: +24 Semitones (2 Octaves Up Only)

Inverted Unipolar: -24 Semitones (2 Octaves Down Only)

Using a 12 Semitone Range

 

You don’t always need 24 semitones.
You can also use a 12-st range — but in this case, make sure you set the modulation to Unipolar, not Bipolar. 

Otherwise, you’ll only get ±6 semitones in each direction.

Unipolar: +12 Semitones (1 Octaves Up Only)

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20 Serum 2 Arp Banks in 5 Scales
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300 Serum 1 LFO Shapes (Arps + Gates)
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Setting The Grid

 

The next step to making arps in Serum 2 is setting the grid.

 

  1. Start by setting the Grid Type to “Bar.”
    This makes the arp loop perfectly every bar, which is the ideal starting point for most sequences.
     
  2. Next, set the vertical axis to 24.
    This divides the grid into 24 perfectly even steps, matching our 24-semitone pitch range.
    (If you chose a 12-semitone range instead, set this to 12.)
     
  3. Set the horizontal axis to 16.
    This gives you the most usable rhythmic divisions that still divide cleanly by 4.
    You can use 8 or 4, but they’re more limited.
    You can also keep the default 12 if you specifically want triplet-based arps.

 

1.Rate = Bar 2.Veritical Axis = 24 3.Horizontal Axis = 16

Important Key Commands For LFO Shapes

To start creating arpeggiated patterns in the LFO, you will also need to know a few more key commands to help you create your LFO shapes. It's very important to in order to snap your shapes to the grid so notes are correct and your groove is locked in sync.

  • Hold Shift and dragging: Step sequencer that snaps to the grid.
     
  • Hold Option / Alt + Shift: Snap the step sequencer to the horizontal and vertical grid. This is what you would use in most cases while making arpeggiated patterns. Snapping the vertical grid locks your positions to the semitone divisions set in the mod matrix.
     
  • Hold Option / Alt: While moving a point will snap the point to the grid.
     
  • Hold Option / Alt: Moving a curve control handle will move all the handles at once.

Stepped Pattern: Hold Option / Alt + Shift

Curved Handles: Hold Option / Alt While Dragging

Creating a Rhythmic Gate

The last step is adding rhythm, groove, and simulating different note lengths by modulating the volume of the oscillator(s). You can get very advanced here by giving each oscillator its own unique volume pattern, but to keep things simple, start by applying the same LFO pattern to any oscillator you’re using.

 

You’ll want to keep your main envelope decay fully open (with a short release in most cases). This ensures the synth plays a full, steady note—because the LFO will now be responsible for shaping the volume and creating the rhythmic pattern.

 

The first thing to do is map the LFO you wish to handle the rhythmic gate pattern to the volume of the oscillator you want to modulate. To make this work as intended, you must bring the range of the volume mod to be 0 to 75. The default gain on the oscillators is 75 – You can go louder but I would use the default to prevent clipping. Also make sure the modulation is UniPolar.

Map LFO to Oscillator Level. Range: 0-75

I usually start with a simple 16th-note template: each step is slightly faded to give a plucky feel. From there, you can quickly decide whether you want to lengthen steps to create 8th notes, shorten them for stutters, or introduce rests to create more groove and variation.

Default 16th Note Pluck Gate

Tips & Tricks

Make your rhythmic patterns even more interesting by modulating the curves.

  1. Control + Click the little dot of the curve you want to modulate
     
  2. Go to "Modulate Curves" and choose the LFO bus
     
  3. Assign that LFO bus a modulation source
 Serum2 Modulation LFO Curves

Conclusion

And that’s the magic of LFO-based arps in Serum—total freedom. You get custom pitch moves, independent oscillator riffs, perfect grid snapping, and your own rhythmic engine. It’s not just an “arp workaround”… it’s an entire creative workflow. Once you build a few templates, you’ll find it’s faster, more expressive, and way more fun than the standard arp. From here, the only limit is how weird, groovy, or melodic you want to get.

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