How To Make A Pulsating Bass Sound With Sytrus Synth

How To Make A Pulsating Bass Sound With Sytrus

In this tutorial, I will show you how to make a pretty cool, kind of pulsating bass sound patch with Sytrus.

Download the Pulsating Bass Sound For Sytrus below to follow along. NOTE: It’s an .fst file. It should open in Sytrus automatically when you double click it or drag and drop it to Step Sequencer in FL Studio.

Here’s an audio example:

Ok. To replicate that, first, open the FL Studio’s Sytrus and reset it by choosing ‘Default’ preset from the preset library.

At this point, it’s a good idea to drop the Master volume level a little to avoid distortion because things will get quite loud as we move on.

Drop The Sytrus Main Volume

Now, go to the OP1 (Operator 1) tab.

Operator 1 Tab

In Sytrus and other FM synth VSTs (like TAL Noisemaker for example), the modules that produce or control the sound are called ‘Operators’. In this default preset, the Operator 1 is generating a pure sine wave.

So first, set the Frequency ratio to 1.0000. This drops the base pitch of the operator down by one octave.

Drop The Frequency Ratio Of Operator 1

Each operator module in Sytrus contains a set of tools that can be used to modify the shape of the oscillator.

Oscillator Shape Modifiers

Use the SH (Shape) fader to morph the shape closer to a triangle wave. This’ll make the base sound of this patch a bit more ‘sharper’.

Operator 1 Shape Value

To control the amplitude of the oscillator in a given time, it needs a volume envelope. You can enable it by setting the Editor target to Volume (click the VOL tab) and Articulator part as Envelope (click the ENV tab) and clicking the Enable envelope check box underneath the editor grid.

Enable Volume Envelope In Operator 1

Now, edit the envelope points: set a short Attack time (the section between first two envelope points), high Sustain level (set it to the point 3/4) and fairly short Release time ( the section between last two envelope points).

Operator 1 Volume Envelope

Next, frequency modulation.

Frequency modulation is the core of the FM synthesis (FM stands for Frequency Modulation). Basically, what this means is that you use a waveform such as a sine wave to modulate (modify) the frequency (pitch) of another waveform. The modulated operator is called a ‘carrier’ and the modulating operator is known as the ‘modulator’. Frequency modulation makes it possible to create complex and tonally rich waveforms.

In Sytrus, you set up the modulation in the Modulation Matrix. Each row represents an Operator and defines which Operator will modulate it and by what amount. The modulation amount is set with the knob. Either positive or negative values can be used. If you leave the knob to the middle position (ALT+left click) no modulation will happen.

Modulation Matrix

What’s the difference between using negative or positive values in the Modulation Matrix? Using negative values will invert the modulation phase, but if you ask me what that means in practice I have to say that I’m not quite sure…

When I was creating this patch, I tried both values and the negative just sounded better. So that is my approach – go by the ear.

So now, make the Operator 2 modulate Operator 1 by turning the knob in row 1, column 2 to left.

Operator 2 To 1 Modulation Level

Set the Frequency Ratio in the Operator 2 to 1.0000. Using lower frequency ratio values in the modulating operator makes the modulation go slower thus producing timbres that MAY be more suitable for a bass sound (I say ‘may’ because sound designing is so subjective art).

Operator 2 Frequency Ratio

Next, edit the shape of the modulating waveform (in Operator 2) via the harmonics editor (you’ll find it under the OSC -tab).

Operator 2 Harmonics Editor

Basically, harmonics editor is a tool to make the waveforms sound richer. You can also use it to create ANY type of waveform.

Without going too much in detail “what’s happening under the hood” (and I don’t understand it fully myself either), there are 128 harmonics in total which amplitude level (see those upper facing bars) and phase (downward facing bars) you can set (draw) with your mouse. The harmonics will then be mixed with the current waveform making it possible to create a wide range of waveforms with different tonal quality.

Before we move on, note this: we are now in the harmonics editor of an operator module (Operator 2) that is MODULATING the Operator 1 so every change we make to the waveform harmonics or shape affects on how it MODULATES the waveform of Operator 1.

So now, use left mouse button to draw some harmonics to the harmonic editor.

Edit The Harmonics In Operator 2

Click the ‘smooth’ button few times to apply smoothing to the harmonics amplitude levels. This’ll average the levels with their neighbors.

Smooth The Harmonics In Operator 2

Now, use the shape modifier sliders to modify the waveform more radically.

With the SH (shape) slider you can morph the shape between sine, triangle, and pulse. Closer to pulse is our target (though it’s not pure pulse anymore as we made changes to the shape in the harmonics editor).

Operator 2 Shape

With the TN (tension) slider, you can set the tension (distortion) of the base shape. In this example, only a little amount of it is required to add that extra ‘bite’ there.

Operator 2 Tension

With the SK (skew) you can skew the shape. Setting it around halfway is enough in this example.

Operator 2 Skew

Done. Again, remember that the changes we made to this waveform affect to how it MODULATES the waveform in Operator 1. Using the modulation and shape modifiers/harmonics editor, allows you to create an endless amount of different timbres.

Next, enable the volume envelope.

Enable Volume Envelope In Operator 2

Few words here before we proceed: editing the volume envelope of the modulating operator actually controls the amplitude of the modulation level (in a given time) you defined in the Modulation Matrix. So with the volume envelope, it’s possible to create all kinds of shapes and sequences to the modulation level.

Now, click the tempo box to make the envelope length relative to the project tempo (enabling the tempo-based time is useful when you have movements in your envelope that you would like to keep in time with your tempo if/when you decide to change it).

Enable Tempo-Based Time In Operator 2 Volume Envelope

Drop the tension level between point 1 and 2 (that’s the attack section).

Point 1 To 2 Tension Level In Operator 2 Volume Envelope

When you play a note, this kind of attack shape creates a sudden rise to how/when the modulation kicks in at fullest level – of course, relative to the level you set in the Modulation Matrix (when a section in envelope editor is set to 0%, no modulation happens at all and when it’s set to 100%, it equals the level you defined in the Modulation Matrix).

Now, raise the point 3/4 to 100%.

Point 3 Level In Operator 2 Volume Envelope

Point 3/4 is a start of the Sustain section. The point 2/4 (which is the beginning of the Decay section) is set to 100% as well so this means that when you play a note and hold it, modulation happens at maximum level (of course, relative to the level you set in the Modulation Matrix) until you release the note.

Now, create a sudden drop in the release part by raising the point 3 to 4 tension level.

Point 3 To 4 Tension Level In Operator 2 Volume Envelope


Next, make Operator 3 to modulate Operator 1 as well. The aim is to add a sort of ‘metallic’ timbre to the higher frequency area so go to the OP3 tab and raise the frequency ratio to 12.0000.

Operator 3 Frequency Ratio

Now, in the Modulation Matrix, increase the Operator 3 to 1 modulation level a bit – either to positive or negative side. I’m using a negative value in this example because it gives a slightly different timbre (which I liked better, but that’s just a matter of taste).

Operator 3 To 1 Modulation Level

The patch sounds too high pitched so go to the Main module and drop the Master pitch to -24 semitones.

Drop The Master Pitch

Now, to enhance the modulation, add a couple of harmonics to the Operator 3.

Adding Harmonics In Operator 3

Use the shape modifiers to add even more flavor to the modulation.

Operator 3 Shape Modifiers

Okay. Next step is to filter the sound so go to the Filter 1 module (FILT1 tab).

Filter 1 Module

To enable the filtering, the signal needs to be sent to the filter module first and from there to main output. That is done in the Modulation Matrix.

So first, disable the Operator 1 going straight to the main out by inactivating its output. That is done by holding down ALT and left clicking the Out knob in row 1.

Inactivate Operator 1 Output

In the row F1 (that represents the filter module 1), column 1, set the mix level to 100%. This will send the Operator 1 signal to Filter module 1 at full level.

Operator 1 To Filter 1 Level

To hear the signal again, send the Filter module 1 to the main output. So in the row F1, column ‘out’, set the level to 100%. Now the signal of the Operator 1 goes to main output through the Filter module 1.

Filter 1 To Output Level

Now, set the filter type to Vanilla low pass.

Vanilla Low Pass As Filter Type

Ok. Next step is to add that pulsating movement to the sound and one way to do it is to use the filter envelope so go to the CUT and ENV tabs, enable the envelope and tempo-based time to make it sync with the tempo.

Enable Filter Envelope

The aim is to make the filter pulsate so edit the envelope as follows: first, move the point 2/4 to all the way to left. This gives us ultra-short/non-existant attack time.

Envelope Point 2 In Filter Envelope

Next, set the point 1/4 to 0%.

Envelope Point 1 In Filter Envelope

To make the pulsation continuous, we need to loop the envelope so right click the point 1/4 and choose ‘Loop start’ from the menu to set it as loop start point (the loop end point is already set by default).

Set The Envelope Point 1 As Loop Start Point

Move the loop end point (3/4) to 001:01:072. This’ll make the loop repeat 6 times per bar.

Move Envelope Point 3 In Filter Envelope

Raise the Point 2 to 3 tension level a bit…

Point 2 To 3 Tension Level In Filter Envelope


Next, a bit of EQ’ing – go to the main module and use the built-in equalizer to boost the low end. Boost the top end as well.

EQ Boost

Ok. The last step is to enable monophonic and portamento modes (Monophonic mode allows to play maximum one note at a time and Portamento mode makes the pitch slide from note to note – set the slide time via the Slide -knob). You can enable them in the Sytrus Miscellaneous channel settings -box.

Monophonic And Portamento Modes

Here’s how the bass sequence you heard at the top of this post sounds WITHOUT the portamento:

And here’s WITH the portamento:

That’s about it. Here are a couple of quick tips to take this patch a bit further:

Tip 1. Shorten (or extend) the Decay time in the filter envelope to make the pulsation go faster (or slower).

Shorten Or Extend The Decay Time In Filter Envelope

Tip 2. Play with the Cutoff and Resonance levels (and remember that you can automate them as well).

Play With The Cutoff And Resonance Levels

Tip 3. Map the Operator 2 to 1 modulation level (or Operator 3 to 1 modulation level) to the integrated X/Y controller. Proceed as follows: First, set the Operator 2 to 1 modulation level either full left or full right (this way, the maximum value of the X/Y controller equals the full modulation level once we have mapped it).

Operator 2 to 1 Modulation Level Tweak

Next, go to the modulated Operator (OP1) and set the Editor target as MOD (input modulation in this case) and Articulator as MOD X (MOD X is the Modulation X controller knob in the Main module). Leave the envelope point 1/2 to 100% and drop the point 2/2 to 0% (or vice versa). This way, when the Modulation X knob is turned full left, the modulation happens at full level – relative to the level we just defined in the Modulation Matrix – and when it’s turned right, no modulation happens at all.

Map The Modulation Level To X Controller Knob

Now, go to the Main module and tweak the Modulation X knob to control the modulation level. And feel free to automate it.

Tweak Modulation X Knob

Tip 4. Experiment with the Harmonics editor of the modulating operator for different timbres.

Experiment With The Harmonics Of The Modulating Operator

Tip 5. Experiment with the shape of the modulated operator using shape modifiers for even more interesting timbres.

Experiment With The Shape Modifiers

The end. 😎

Watch the video version below:


About Author (HTMEM) - A music production website with plenty FL Studio tutorials, interviews, news, free music production tips, and free downloads.


  1. Thanks for the great tutorial. I have really picked up a lot of things from your lessons, and I’m going to release some mixed and mastered songs thanks to your tutorials!

  2. Ashish Malpani on

    like always brilliant tutorial
    you do a lot of hardowork for us
    just one question
    in your demo audio clip sample how do you get those amazing PUMPING HIGH BASS BEATS
    if you have already done a tutorial can you give a link

  3. Thanks for the great tutorial bro,
    But a question!
    I Don’t know, maybe my question is wrong but the sound have something like LFO! can we change the speed of that?

    • Hey Ali,

      If you mean that slow filter movement in the audio example, you can change it’s speed. I used automation clip to control the Filter 1 module cutoff frequency, but you can also use LFO for that (in the Filter 1 module, set the Editor target to filter cutoff frequency and Articulator part as LFO and remember to enable it as well).

  4. Man this is fantastic. This really clears up a lot of mystery with regards to FM synthesis. Thanks, Petri!

  5. Amazing, as usual. Thanks, i really think this may help me with some of my songs

  6. Hey Petri! That was another awesome tutorial!
    I really learned a lot from your various tutorials and I’ve gone into more professional production thanks to the ideas that popped into my head after watching some of your tutorials like the trance song walkthrough etc.
    Could you listen to this song and give me some feedback?

    Thanks in advance!

  7. Justin P on

    Just wanted to say thank you for all your awesome tutorials, Petri! Best resource on the internet in my opinion, keep them coming!

  8. Ali Inter. Vocal on

    HI MR. Petri Suhonen…
    Dont Have Any Tired.
    I impressing You For this WebSite,
    All Matters,Such As The Video Toturials Are Very Great And Intrested for Me,
    Beacuse There Isn’t Any Kind Of This Sources For Learning In our Languege (Persian)
    Notable I Haven’t HighSpeed & Dial-up internet At Home But I Stay At The Internetcaffee For Any Hours
    Just For Learning Something From Your Web.
    I Just Say That Your Web Site Is One Of The Compllet And Corecrt Source Of The Music Making
    In the Cyber Worlrd.The Topics Are Very Intressting For Me.
    I Learned 90% Of The Mix And Mastering Techniques or etc… From Your Web.The Video Tourials Are
    Best Way For Training.
    I Waiting For Your Next Cool Toturials

  9. Lee Sihun on

    You’re the best, Petri! I’m always learning a lot from you
    hey, could you tell me how you attach music files on your posts?
    what is that flash player called?

  10. Alex Dickson on

    OMG This inspired me sooo much!!! I never could figure out how to use Sytrus until I watched this. THANK YOU THANK YOU THANK YOU!

  11. Hi Petri, I just found your site and I have to say it is awesome- I loved the video tutorial version of this, mouse dancing and all. 😛

    Making electronic music is something I’ve always wanted to try and thanks to your tutorials the idea has shimmied out of the ‘impossible’ bin in my head and over into the ‘hell yeah I can do that’ side. Thanks.

  12. from iran (city of sari) on

    hi Master. Thanks for the great tutorial. I have trained a lot of things from your knowledge.

  13. Sourab Vadlamani on

    Hey can anybody help me please.
    I’ve made a few tracks ( only music no vocals ) but I don’t know how to release them.
    Please tell me what to do next. Making music is all I want to do when I grow up ( am 16 ).

    • Sourab Vadlamani, polish your work as much as you can, then put it on Youtube. Ask for comments and how to improve.

  14. So I saw this sweet tutorial, and I used some of the stuff in this one and I got an awesome metallic pad with heavy bass from this. There is the link to it, any feedback?

  15. I’m using your .fst and the note doesnt fade out before the bar ends like yours, how can I make it do that?

  16. Hi, i was wondering if you could make a tutorial on how to make edm style claps!!! If not, could you send them to me please with the email adress above

  17. Two Fingers Lydon on

    Thanks so much for this. I tried to follow a MT magazine tut using sytrus and I felt like a complete effing moron because I wasn’t getting it. THIS makes a whole lot more sense. They should hire you guy!

  18. Sytrus is one of the default plugins fl studio best, I often use it in making the bass. thanks it works