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Oberon – Tutorial 5 : X-Morph

Oscillator morph function.
Oscillator morph function.

An interesting feature of the Oberon Synthesizer is the ability to morph between two spectrums. With this you can create interesting crossfades between two different sounds, for example between an inharmonic one and an harmonic one. Sometimes the result is somewhat unpredictable but it is a definitely a place for experimentation. Lets take a closer look.


As said in the introduction, Oberon’s cross morph feature works with spectrums. It is not trying to morph between waveforms but between the corresponding “instantaneous” spectrums of oscillator 1 or oscillator 2. Before going into too much explanations, lets dive in and listen to what this does.

Start by creating an Oberon device then reset it to a default configuration. With no surprise you should hear a classic sawtooth when playing it. Now play around with oscillator 1’s x-morph knob. Hopefuly, you should very quickly come to the conclusion that nothing changes. How frustrating.

This is of course is very logical. Oscillator 1’s x-morph function lets you morph between its output spectrum and the output spectrum of oscillator 2. This works even if oscillator 2 is disabled, by the way. When Oberon is reset to its default configuration, the output spectrum of both oscillators are totally identical. They both use the same wave, with the same wave sequence position, are pitched identically and have their bend and partial clip modifiers muted (for more information on these two, check out the dedicated tutorial).

To hear something, we need to make oscillator 2 different. Lets change its wave by putting the wave position of oscillator 2 to 50%, which by default should be a triangle wave. Now, play while increasing oscillator 1’s x-morph knob:

As expected, the sound gradually fades to a triangle wave. Things aren’t quite exciting yet as this could already be done with the Waves 1 & 2, although with not exactly the same result. Now lets use a “metal” wave on oscillator 2 and play again while increasing the morph position:

As you can hear, the sound changes to metal smoothly and in a way that is different from a simple crossfade.

Metal Attack

With that in mind, lets create a patch that has a metallic attack and then fades to a triangle wave. For a reason that will become clearer near the end of the tutorial (and is purely related to the final patch we have in mind), lets use the metallic wave on oscillator 1 and the triangle wave on oscillator 2. Again, the triangle wave is by default in Wave 1 with start position set to 50%.

If you set oscillator 1’s x-morph position to 100%, played on a C2, you should hear this:

There is a strange beating / oscillation going on in the low end. We will come to that later on but that will be our end sound.

As we want the attack to be the metal sound, we need to use an envelope to modulation the x-morph position. We can use any three of them but as the first two are hard-cabled to the respective filters, lets use modulation envelope 3 for that. The default shape for this envelope is an instant attack decreasing curve, which is perfect for what we want.

Configure the modulation matrix by setting on the first line the source to “Mod. Env. 3”, the destination to “Osc1 – Morph. Pos.” and the strength to -100. The default value of the morph position is set to 100% through the knob and we want it to be 0% on the attack, hence the -100 strength. If you are not familiar with the modulation matrix, we invite to read the documentation on Thor as Oberon’s modulation matrix is very similar. This is what the matrix should look like, once properly set:

Modulation Matrix

Lets play the resulting patch:

I’m not quite satisfied with this. First of all the attack is a bit slow and second, the sustain sound is not quite what we had without the envelope modulation. But that’s just a few clicks away to resolve. We need to shorten our envelope and lower the sustain level to something that is similar to this:

Shorter Attack

Adding a layer

Lets move on by adding a new layer to our sound. This time we will take a look at oscillator 2 so lower oscillator 1’s level to 0, push up oscillator 2’s level to 0 dB and active oscillator 2. For the moment we have a flat triangle tone:

By default, oscillator 2’s morph feature takes oscillator 1 as a target spectrum. If we keep it that way we will morph towards the metal wave which is already what we are doing with the other oscillator. Instead, lets morph oscillator 2 to… oscillator 2! It sounds completely useless as is but is more interesting if we decide to morph oscillator 2’s spectrum to that same spectrum but transposed. Again, lets first listen to what this does.

Configure oscillator 2’s x-morph section like the image below by clicking on disabling the “Osc. 1” button and turning the transpose knob to the left to the +19 semitones value.

XMorph ConfigNow play the patch while increasing the morph position:

The first thing we notice is that morphing between a transposed version of the same oscillator isn’t just a simple pitch bend. Some interesting low frequency growling appear that we could take advantage of. The other thing we can notice is that even with morphing at 100%, the resulting sound isn’t completely a triangle wave transposed higher. Well, now’s the time for an explanation.

Morph curve

By default,  Oberon’s morph feature operates on the medium and high pitch partials of the spectrum, leaving the low pitch intact. This is to try to preserve the note pitch of the sound. So even at 100%, some parts of the spectrum correspond to the source spectrum while the rest are part of the destination spectrum. In between, some partials can be pitched half-way, yielding some inharmonicity. This is what we heard in our previous attempts.

Thankfully, we can override this behavior easily as all this is done, again, through a curve. Click on the right side “XMorph” button of the display buttons “Curves” section. This controls the x-morph intensity for each part of the spectrum. Your central display should now look like this:

XMorph CurveHigh level values of the curve indicate that x-morph should occur at full value at that position. As you can see, there are a few curve templates mainly for protecting the low end of the spectrum (which is basically the default) or on the contrary, the high end. The one that we are interested in is the “All” preset which sets morphing intensity to full value everywhere on the spectrum. Click on the “All” preset button and move the “Zoom” scrollbar fully to the right to have this display:

All X-Morph Curve

The numbers displayed (2, 4, 6, 8, …) indicate the harmonic rank positions. As you can see the curve rises directly to full value at where we can assume is the rank 1 (which corresponds to the note pitch, if you are now familiar with additive synthesis) position.

With that new curve, lets play our patch, again with an increasing morph position:

This time we can clearly hear a square wave, just an octave lower, when the morph position is at 100%

Finishing Touches

Now that we’ve hear what x-morphing to the same oscillator does, lets use this to our advantage and link that effect to the modulation wheel. Set oscillator 2’s x-morph position knob to 0%, set the source on the modulation matrix’s second line to “Mod. Wheel”, the destination to “Osc2 – Morph. Pos.” and this time intensity to 100%.

Modulation on Osc. 2

Turn back on oscillator 2 by pushing the corresponding level fader to 0 dB and slightly detune both oscillators a handful of cents (for instance -5 on oscillator 1 and +5 on oscillator 2). Now play a little tune while playing with the modulation wheel. You can even use some harmonize (like we did, at 75, with the harmonize octave set to -1) if you find it really too inharmonic:

Finally, to give it more character, lets apply a “Bell” template to our amplitude envelope curve and crank down the filter 1 frequency to around 600 Hz. Now we’ve go an interesting little metal pluck with a sort of larsen control on the modulation wheel:

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Oberon – Tutorial 4 : Unison & Octave

8x Unison and Octave virtual voices per oscillator.
8x Unison and Octave virtual voices per oscillator.

After discovering in the last tutorial the more complex features of Oberon, today things will be lighter… and fatter. Yes, in todays modern music, we like it when sounds get fat, thick and deep. With its two oscillators, Oberon can already give you a certain amount of that by layering these two oscillators together.


At the center of Oberon lies the mixer which lets you control various levels of the synthesizer, including, most of all, the output levels of both oscillators controlled by the two left-most faders. By default, and in our current bell patch, you should notice that fader 1 is at full value and fader 2 at its lowest. Sure enough, only oscillator 1 can be heard. Push up fader 2 to the maximum value and press a key.

Oscillator 2 enable buttonNothing has changed, right? By default, oscillator 2 is disabled for performance reasons. It’s very easy to correct that as we just have to click on the enable button at the left of the “Oscillator 2” section label. Now play again. This is what should come out of your speakers on a C2 note:

You can listen only to oscillator 2 by lowering oscillator 1’s output level to the minimum. We recognize a saw wave with a modulated low pass filter. That’s perfectly logical as we can see that oscillator 2 is using Wave 1 (which is a saw wave by default), with the start at 0%. The oscillator is also routing its output to both filters in serial, hence the modulated low pass sound.

That saw wave on top of our bell sound isn’t really the character we want. Lets switch oscillator 2 to a softer and leaner triangle wave sound by turning oscillator 2’s start knob to 50%. We gain a stronger harmonic feel while keeping the bell characteristic:

We can furthermore tune oscillator 2 differently from the first one for a different sound. Here we’ve tuned it an octave higher by setting the Octave knob to +1 and slightly detuned it with a Fine knob at -7:

Layering oscillators is an effective way to enrich our sound. Unfortunately, it can sometimes be cumbersome to reconfigure entirely a second oscillator when you only want a slightly detuned copy of the first one.


Thankfully, Oberon can generate an exact copy of each oscillator but an octave higher. This is great for fat bass sounds or rich string sections. By the way, that copy is not done through a third or fourth oscillator so it is extremely efficient on your CPU.

In the mixer section, the two faders labelled “Octave Levels” control the levels of these two “octave copy” virtual oscillators. Push up oscillator 2’s octave level to the max:

The sound is brighter that’s for sure but we’re not quite convinced by the result. Let’s mute oscillator 2’s octave copy and turn up oscillator 1’s octave copy:

That’s more bell-like and there is also an unexpected chorus-like effect, too. Lets keep this.


Unison sectionIn the same manner that Oberon can generate lightweight octave copies of each oscillators, it can also create multiple slightly detuned (in the order of cents) copies of them. To do this, we first need to set the number of these virtual copies in the oscillator’s Unison section at the bottom. Lets start with 4. Instantly our bell sound becomes lush and dreamy:

Phase control

You may notice when listening carefully that the attack of our bell sometimes becomes softer or slower. This seems to be somewhat random. This is due to the difference in phase between each virtual copy and the original oscillator sound. When a new note is pressed, that start phase is different for each copy. When all copies and oscillator are nearly “in phase” we have a nice attack but when they are “out of phase”, the attack becomes softer because some virtual oscillators start out by canceling each other out. This is not really problematic for slow attack sounds but for us, it’s not quite satisfying.


Thankfully, we can counter that by enabling the Lock button of the unison phase section. That will ensure that at each note press, each oscillator is set to the same start phase. All copies are “in phase” with the oscillator. This will give us a very powerful attack and we might have to control that by lowering the gain. Lets hear what this does on our bell:

Sure enough, the attack of our bell is now strong and clear.


If you feel that attack is too strong, we can enable the “Random” feature on the unison phase. This has the effect of randomizing the phase for each unison partial. With lock enabled, we will have random start phases for each unison partials but these phases will remain the same for each key pressed, which is exactly what we want. Lets listen to the result:

That sounds perfect: a nice lush consistent sound.

By the way, modifying the phase for each unison partial results in change in timbre, especially on harmonic sounds and can also be used for that effect.

Tuning and Mix

An important parameter for unison is the amount of detuning applied to these virtual copies. Low values will give slow phasing effects while high values will yield the famous “hoover sound”. Controlling that detune value is done in the mixer section with the Unison Detune faders. Lets first try changing the detune value of oscillator 1’s unison to a very low value of 4:

The sound is definitely thinner. Now lets try with a detune set to 75:

Very, very lush but it sounds almost out of tune. We can revert back to a lower detune value but lets try an alternate route by playing around with the Unison Mix.

The mix value controls the dry / wet mix between the direct oscillator output and the virtual unison copies. Lets lower that to 40%:

That’s certainly better as the “out of tune” feel is really under control now but will still retain that very high lushness to our sound.

To finish off this tutorial, lets crank up all these virtual copies to the maximum by putting oscillator 2’s octave level to the max and enabling an 8 voice unison on that same oscillator. How’s that for a nice lush bell sound?

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Oberon – Tutorial 3 : Modifiers

Manipulate oscillator spectrums with bend, harmonize and clip.
Manipulate oscillator spectrums with bend, harmonize and clip.

In the previous tutorials we have manipulated Oberon in ways very similar to classic subtractive synthesis. For this third tutorial we will start using some features more specific to additive synthesis: bend, harmonize and partial clipping. All these features modify the spectrum of the sound at a partial level. But then again, under the hood, in additive synthesis, everything comes down to modifying the partials.

First of all, let’s start with a clean sheet by creating an Oberon instance and reseting it. Set the wave start of Oscillator 1 to 50% so as to use the second shape of Wave 1. You should hear a classic unfiltered triangle wave sound.

Partial Clipping

The first partial modifier we will explore is located at the bottom left of the Oscillator 1 section and is labelled “P.Clip”. To better understand what is happening, you can open the spectrum EQ window on the Oberon rack or just rely on your ears. Let’s first play a note while cranking up the P.Clip knob:

As you can hear, the sound gets brighter and harsher with increased partial clipping. If we put back the wave start to 0% to play a saw wave (the default Wave 1 shape 1, remember), the effect is even more noticeable and the sound is almost nasal:

Looking back our spectrum EQ window, here are the two saw spectrums, one without partial clipping and the other with a full effect:

No Clipping
No Clipping
With Clipping
With Clipping

As you can maybe deduce, partial clipping has the effect of soft clipping the partial levels. In other words, it will boost low level sections of the spectrum while slightly lowering or at least maintaining high level sections. But then again, if we don’t want to delve into that much detail, we can also just see this as a “brighter” or “harsher” knob!

Let’s set back the wave start to 50% to have a triangle wave and put the partial clipping to around 75%. This will be our base timbre for the tutorial and it should sound like this on a C2 note:


For the moment we have just played around with spectrum levels but another nice aspect of additive synthesis is that we can also change the pitch of parts of the spectrum. Remember, additive synthesis lets us control individual portions of the spectrum through partials. This is done with Oberon with the Bend feature.

Again, prior to any explanation, lets just hear what this does:

It kind of sounds as if we were upwards pitch bending our sound but not quite as the timbre also changes to become metallic or bell like. Again, if we take a look at our spectrum window before and after bending, something pops up:

No Bending
No Bending
With Bending
With Bending

The peaks identifying the harmonics of the sound seem to have been displaced to the right of the spectrum, that is, to the higher frequencies. The effect seems also more pronounced as we go up in frequency. Let’s play a small melody, without and then with 50% bending:

As we can hear, the pitch or notes remain the same. It is just the timbre that changes to become really more metallic or glass like. That is pretty normal as the sound becomes less and less harmonic as the partial pitches are displaced from the harmonic frequencies, which is exactly what happens in bells, metal rods or very rigid strings: the frequencies produced are not harmonic. If you increase your guitar string tensions to an insane amount, apart from pitching the note up, you will also notice this effect.

If you don’t want to go into much detail, you can just stop there and consider the bend modifier to be analog to a “string tension”, “metallize” or “glassify” effect. If you are more curious and power hungry, let’s dive.

Bend curve

You may have noticed in the series of display buttons, next to the envelopes and waves, two buttons labeled “Bend”. It’s time we take a look so lets press the one on the left, associated with Oscillator 1. The top display changes to this:

Bend Curve display

Again, this should look familiar now that we’ve manipulated the envelopes and wave display but a big question arises: what does that curve manipulate? First of all, let’s play around with the different curve templates on the left.

To hear the full effect put back the oscillator 1 bend to 100%. Then let’s select “Buzz” and play:

Buzz curve

A low frequency buzzing or beating can be heard, depending on the note played.

Now select template “Octave” and play around again:

Octave curve

This time the sound is harmonic but it has lost its characteristic “triangle / square” sound to become closer to saw timbre. Intriguing…

Finally, select template “Stiffness” and play:

Stiffness curve

That sounds like the original bend effect we started with and, as the name suggests, could correspond to an increasing string stiffness / tension.

Now, what exactly is going on here? Bending has the effect of increasing or diminishing the frequency spacing between partials in your oscillator’s spectrum. Said differently, it has the effect of contracting or stretching the frequencies of parts of your spectrum. With it you can mimic physical behaviors, like increased string tension, or completely crazy unpredictable stuff.

Curve points above the middle line will increase the frequency spacing and points underneath will contract it. The left start point of the curve is always the fundamental frequency of your note and that cannot be bent so as to keep your overall pitch intact. As we go towards the right side, the curve impacts higher harmonics.

With all this, we can understand the bend curves better. Lets start with the first “Buzz” curve. The lower harmonics are unchanged but higher harmonics are contracted, giving the illusion of a low frequency sound, hence the buzz or beating we hear.

With the “Octave” curve, we have the inverse effect. All harmonics except the fundamental have their pitch scaled up. We can’t really see it in the display but, believe me, they are scaled up by one octave. This is why the effect retains the harmonic character of the original sound. To position your bend curve points on octaves (either up or down), simply enable the “Snap Y” checkbox at the upper right of the curve display. This will have the effect of snapping your points vertically to octave positions.

Finally, with the “Stiffness” curve, we can see that, as we deduced from looking at the spectrum EQ window, as we go higher up the spectrum, the partial pitches are more and more stretched upwards. This, again, replicates the harmonic distortion of a very stiff string.

Ok, enough theory and curve manipulation.

Creating a bell sound

With this bending feature, it is extremely easy to create bell sounds. Just crank up the bend and add some filtering. Thankfully, there is a “Bell” envelope preset we can use both for the amplitude and modulation 1 envelopes. Here’s our try on a bell patch with bend set to 100% with the default “Stiffness” curve, the filter 1 frequency set to 700Hz and both amplitude and modulation 1 envelopes set to “Bell”. We’ve just moved the amplitude envelope’s sustain point to around 3 seconds for a longer decay. Listen to this:

I don’t know what you think of this but, although it may sound realistic, there is a slight off-tune character to the patch that I don’t really like. Let’s see how we can fix this.


That slightly off-tune characteristic of our patch is due to its inharmonic nature. We could counter balance this by reducing the bend but that might alter our timbre too much. Thankfully, we have a second option with the Harmonize knob.

Harmonize is a very simple but effective mean of forcing your oscillator back to musical territory. It gently pitches back all your partials to the nearest harmonic frequency. We can hear this by increasing the harmonize strength as we play:

There is a slight change of timbre but much less pronounced than with altering the bend. If you are still not satisfied, we have another trick up our sleeves. By default, the harmonize feature forces back the partials to harmonic frequencies of the current note. We can instead ask to use the harmonic frequencies of the same note but one or even two octaves below. This will keep our sound harmonic but with sub-octave harmonics. Since sub-octave harmonics are closer appart (the distance between two harmonics is exactly the note frequency, remember), our harmonized oscillator will have a higher chance of sounding like the original oscillator.

Let’s try this on our tune with harmonize set to the full value at the default “0” octave setting, then the “-1” value and finally the “-2” octave setting:

Still not satisfied?


We have another trick with the Limit setting of our harmonize feature. By default, the harmonize works on all parts of the spectrum. But with the limit knob we can decide to limit the effect to the low end thus keeping some inharmonic partials in the high frequencies while retaining the benefit of harmonize and keep a more distinct note pitch which is essentially determined by the lower harmonics.

To hear this, put the octave setting back to 0 and play with the limit by turning the knob to the left until you are satisfied. We want to keep a metallic aspect to our sound but we wish to keep it in tune. To our ears, putting the limit around 33 sounds just fine:

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Oberon – Tutorial 2 : Filters

Filter controls

In the previous tutorial, we explored how to define the basic timbre of an oscillator. Although Oberon is an additive synthesizer at its core, it has a number of features that resemble the classic subtractive architecture that is the basis for most of the synthesizers from the very start. Most importantly, it also has filters.

Filters are great to quickly sculpt your sound by removing or boosting large portions of your spectrum. Classically, a synthesizer filter consists of a low pass profile which attenuates frequencies above a certain frequency value. Modern synthesizers can switch to alternate profiles like high pass or band pass.

Oberon offers two filters which are identical in nature. As we will see, each of them can alter the sound of both oscillators. But lets see how things are done in Oberon.


This should be very familiar to you as this controls the cutoff frequency of the filter. By default, both filters have a low pass profile. You can verify this by pressing a key and playing around with Filter 1’s frequency parameter. In the following example, we’ve set the frequency value to a low value of around 200Hz. If you proceeded from tutorial 1, you should hear something like this, much less brighter than the sound we had at the end of tutorial 1.

Envelope modulation

If you listen carefully, you should notice that the attack of the sound is much brighter than the sustain part. Something is amiss with the filter frequency. There is no bug or magic there but just the effect of modulation envelope 1 modifying the filter frequency over time. Both filters 1 & 2 have their frequency parameter modulated by respectively modulation envelope 1 & 2. The amount of modulation is controlled through respectively the Mod Env 1 & Mod Env 2 knobs to the left of the filter frequency knobs. As you can see, by default there is a fair amount of modulation going on. Try setting it to 0 (middle position) and you should hear a sound that is fairly dull and static:

The modulation depth of the envelope can furthermore be modified by the velocity. This is great for dynamic bass sounds for example and is controlled by the Vel knob just underneath the modulation envelope knobs. If you set the velocity knob to full value and the modulation envelope depth back to the original value of 65, a low velocity note will have almost no envelope modulation, while high velocity notes will have the full modulation depth of 65. This is an example of what it should sound like playing notes with gradually more velocity:

Editing the envelope

To edit the modulation envelope 1, which is the one modifying the filter 1 frequency, click on the Mod 1 button of the Envelopes display section just underneath the top central display. You should see this:

Modulation Envelope 1Just like the wave curve display, to the left are a list of envelope templates, crazy or classic, to let you quickly set your envelopes. But of course, you can also modify them by moving the points around and adding / removing them. You should notice something new, though.

First of all, above the curve frame is a small “S” label. This identifies the sustain point. If you wish to modify this, just click on one of the rounded boxes above each point. In Oberon, all points before the sustain point are considered part of the attack while all points after are considered part of the release.

Lets try to create a more “picked bass” sound by shortening the envelope attack. You can do this by dragging the sustain point to the left or by using the quick edit button to the right of the curve display labelled “Shorter Att.”. This will scale down in time all points before the sustain point. Here’s our modulation envelope after shortening the attack:

Shorter modulation envelope 1 attack

To have even more dynamic velocity in our sound we’ve increased the filter 1 modulation envelope 1 depth to the full value and brightened it up a little by increasing the filter frequency to around 560Hz. With our new envelope, here’s our sound with increasing velocity:

Filter Curves

Now that we’ve played around with the cutoff frequency, the most acute readers among you should wonder if Oberon has any resonance setting. The answer is: yes, and even more. To the top right of the frequency knob you should see a small knob labelled “X-Y”. Try increasing it to the full value and listen to the sound:

Sure enough, we recognize the typical funky squeal sound characteristic of a high resonance value. So why call this knob “X-Y”?

In Oberon, there is no such thing as “resonance”. The synthesizer uses a more broader scheme based on two filter profiles for each filter. Each filter has an X profile and a Y profile. By default, filter 1, for instance, has a low pass profile assigned to the X profile and a resonant low pass profile assigned to the Y profile. Changing the X-Y knob towards the right (towards Y) gradually morphs the final filter between this flat low pass profile to a squeaky resonant low pass profile.

Now the interesting part is that each X and Y profile can be edited for both filters the same way as wave forms or envelopes can. This implies that you can very well decide that the X profile is a low pass profile and the Y profile a high pass profile. Lets see this in action by clicking on the X button of the Filter 1 display. Here’s how your display should look like:

Fitler 1 X curveAll this should now be familiar as you recognize a list of curve templates to the left, with the classic low pass, band pass, high pass profiles and some other more esoteric ones. Sure enough, the X filter curve which defines the X profile looks definitely like a low pass filter. The low end is at 0dB gain. Every point above it creates a gain (like a resonance), while every point underneath creates a cut (like a notch). In fact, if you are accustomed to graphical equalizers, you should feel right at home.

At the center of the display, labelled “0 semi” is the cutoff frequency. Everything to the right is above the cutoff frequency and everything to the left are lower frequencies. The labels “-4 oct.” and “4 oct.” indicate that at this horizontal position, the frequency is 4 octaves lower or higher, respectively than the cutoff frequency.

Lets switch to the Y curve by clicking on the neighboring Y button:

Filter 1 Y curve

The peak is our resonance and as we can see, it is perfectly centered on our cutoff frequency. This is not an obligation and we can easily change this with the usual point dragging and “Add / Remove point” features. Lets try something complicated with two resonance-like peaks like this:

Double resonanceWith the filter 1 X-Y knob fully turned to the right and with a slight global volume attenuation to prevent clipping, this is what it sounds like:

Now with the X-Y knob on filter 1 we can go from a normal low pass filter (approximately sounding like a 24 dB/octave filter) to a low pass filter with character. If you wish you can link the modulation wheel to the filter 1 X-Y parameter with the modulation matrix.


There is another little thing we can do with filters and that is to repeat the filter response. You may have noticed this weird “Repeat” button under the filter curve to the left. Pressing this will change how the curve is applied as a filter response. When activated, the response is repeated across the frequency spectrum with a period defined by the filter frequency. For instance, if we activate repeat on our current filter setting with a filter frequency of 550 Hz, the filter curve controls the gain and attenuation of the spectrum for a 550 Hz wide band that is repeated every 550 Hz.

Filter repeat

Again, using the spectrum EQ window will makes things clearer but here is a diagram showing the differences with non repeated filter curves first then repeated filter curves.

Non repeated filter curve Repeated filter curve

Repetitive filters like this are not uncommon in classic subtractive synthesis. Comb filters behave exactly the same way with repetitive peaks or repetitive notches.

Lets listen to our patch with repeat activated:

Filter Modes

Filtering ModesTo finish off this tutorial on filters, we will take a look on how both filters are applied on oscillators.

By default filter 1 & 2 are applied in sequence / serial. Pressing the button over the “Filtering” label between the oscillator and filter sections reveals a popup menu with all the available filtering modes for each oscillator.

For performance reasons, it is sometimes interesting to switch to no-filtering or to a single filter only if the other has no effect. Just to be tidy, we will switch to Filter 1 Only. Hopefully the sound should remain the same!

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Oberon – Tutorial 1 : Waves

Two oscillators with identical parameters.
Two oscillators with identical parameters.

Creating a patch with the Oberon Synthesizer always starts with the oscillator section. This is where the raw sound is produced. If you are a bit familiar with basic synthesizer architectures like the ones found in the Reason stock devices Subtractor or Thor, you should feel confortable with Oberon’s oscillator section, at least for the basic settings. If not, we invite you to read a first brief Introduction to subtractive synthesis which is the heart of these architectures.

First of all, lets start with a clean sheet by creating an instance of Oberon and reseting the device (right click on the device and choose “Reset Device”). For this tutorial, we will only use the first oscillator, which is the only one active by default. So no need to change anything for the moment.

Basic Settings


Lets first get rid of the obvious and very basic settings, the pitch. By default, the pitch of a sound is determined by the note of the key you press. For instance, the C4 key generates a sound at a corresponding C4 pitch, which generally corresponds to frequency around 261-262 Hz. We can transpose this by octaves using the Octave knob, lowering the pitch for negative octave values and vice versa with positive values between -4 and +4. Likewise, the Semi knob transposes the pitch by semitone increments, between +0 and +11. Finally, the Fine setting lets you do micro adjustments to the pitch by 1/100th of semitones. This is great when both of Oberon’s oscillators are activated, each one slightly detuned for that very classic fat lush sound. But lets stick to one oscillator for the moment.

You can keep the pitch to the default setting for the time being. If you press the C2 key you should hear a beautiful rich sawtooth wave that sounds like this:


If you have a stereo speaker setup or, even better, headphones you should hear the above sound as a mono fully Pan and Widthcentered sound. Both oscillators in Oberon have a separate Pan and Width knob to control the placement and width in stereo space. Oscillator 1 settings are the left knobs.

While the pan setting is fairly obvious, the width needs some extra explanation. Due to the nature of its audio engine, Oberon can spread the spectrum of its oscillators across the stereo field making each oscillator true stereo oscillators. This may alter the timbre slightly as parts of the spectrum will be completely to one side leaving “holes” in the spectrum on the other side. Hopefully, when the width is to the maximum, you should feel the stereo field is pretty well balanced.

Press the C2 key while progressively increasing the width of oscillator 1 and you should hear something like this (headphones or stereo speakers required, of course):

Ok, lets keep the width to a low level just to have a slight width by setting it between 15 and 17.

Controlling Timbre

Wave types

Sawteeth are great but, thankfully, the Oberon oscillators can generate much more. Right at the top of the Wave Typesoscillator section is a display with the name of the current wave, here “Wave 1”, which corresponds to a sawtooth. The type of the wave defines the timbre of the oscillator.

If you press the button to the left of oscillator 1’s wave type display, a popup menu appears with the list of all available waves. As we will see later on, waves 1 & 2 are a bit special. You can change the wave types and listen to the different timbres they produce. Some of them sound frankly out of tune and not very musical, especially the Metal, Water, White Noise and Crowd ones. These waves are “inharmonic” or not harmonic.

Choose the Oberon wave. It should sound like this on a C2:

It is not the sexiest sound in the world.

Wave sequences

In classic subtractive synthesizers, a wave is defined by its shape in time. By repeatedly playing that shape, the synthesizer creates a periodic musical sound with a defined pitch. The shape defines the timbre and the duration of the shape defines its pitch. By changing that shape over time, instead of repeating it but by keeping the same shape duration, a synthesizer can generated a sound of evolving timbre but of constant pitch. A wave table or wave sequence, is a sequence of shapes that defines what shape the oscillator should generate depending on a position in that sequence. That position can be static, in which case the oscillator produces repeatedly the same shape, or in movement backwards or forward, at different speed levels.

In Oberon, things are slightly different due to its more generic additive engine. To each wave shape corresponds a corresponding sound spectrum. The two are completely analog and are two different ways of identifying a timbre either by looking at it in the time domain or in the spectral / frequency domain. This is even more obvious and is a nice way of working with Oberon when sound designing when you display the spectrum EQ window of Reason.

If you press, again, the C2 key on your keyboard you should have something like this displayed in your spectrum window:

Oberon Spectrum You can notice, if you keep the key down, that the spectrum is static and doesn’t change over time.

Oberon waves are in fact wave sequences. By default, the first “wave form” is used. “Wave form” isn’t an appropriate term in Oberon as it suggests, as in classic subtractive synthesis, that they are defined shapes that are played repeatedly. In Oberon, wave sequences are really spectrum sequences. Each entry in the sequence is a different spectrum. That may seem like not much of a difference but in fact it makes a huge difference because a spectrum may not necessarily correspond to a periodic musical sound. If you listen to the Metal or White Noise waves, for instance or even better, record them and have a look at their shape, you will notice that they do not sound musical, don’t have a really defined pitch and absolutely don’t have a periodic wave shape!

By working with spectrum sequences, Oberon can create timbres that evolve from periodic musical tones to completely metallic inharmonic ones, which is totally impossible to do with classic synthesis.

Wave Start

The Start knob in the oscillator section defines the position in the sequence that the oscillator should use to look-up the spectrum for the timbre. Each wave type has a different number of spectrums in their sequence but all sequences loop back to the first spectrum when start is set to 100%: the spectrum at 0% is the same as 100%.

With the wave type set to Oberon, if you press the C2 key and play around with the start knob, you should hear something like this:

Notice how the display in the spectrum EQ window changes with each change of the start parameter.

Wave motion

While moving the start knob manually can give fun results, half of the time, we would like the sequence to play automatically. The Motion knob controls the speed of the sequence play back. When you press a key, the first spectrum played is the one indexed by the start position. Afterwards, Oberon automatically increases the position based on the motion parameter until you release the key. Of course, by default, each note has an independent sequence position but that can be changed by disabling the key sync button.

This motion can be set to move forward in the sequence, or backwards but the sequence position will always loop. The motion speed is by default synced to the song tempo but again, this can be changed.

Lets play our Oberon wave with a bit of forward motion. Set the start to 0% and the motion to 1/1 by turning the motion knob about half-way to the right. A motion at 1/1 indicates that the wave sequence will be looped every bar. Press our faithful C2 key and you should here an emotionally devoid robot repeatedly saying “Thisss izzzzz Oberrrr-t-on”. Or something fairly close.

If you press different keys on your keyboard you should notice that the speed of the phrase remains the same while being pitched accordingly.

Editable waves

When we first presented the wave types, we stated that Waves 1 & 2 were special. But in what way? Well, they are editable. Waves 1 & 2 are very simple wave sequences made each of two wave forms / spectrums. Since, again, every wave in Oberon loops back on its start spectrum, if you choose Wave 1 or 2 as a wave type, the first wave form of the sequence is played when the start is at 0% or 100% and the second wave form is used when the start is at 50%.

To get a look at the default wave forms used for Wave 1, for instance, just click on the button labeled “1” of the two “Waves” buttons. Pressing these buttons changes the big central display of Oberon to the current wave, where, by default, it displays the amplitude envelope. If you want to go back to the amplitude envelope, just click on the “Amp” button of the “Envelopes” buttons. If you pressed the Wave 1 display button here is what you should see:

Wave 1 start curve

As you can recognize, this is a descending sawtooth. To the left of the central display are a series of wave shape templates. Clicking on them will apply the templates to the curve. Try clicking on CZ for instance and you should see this shape:

CZ wave shape

To hear what this sounds like, choose the Wave 1 wave type on oscillator 1, set the start knob to 0% and don’t forget to put back the motion knob back to “Off”. Hopefully, on our classic C2, this is what you should hear:

To display the second shape of the Wave 1 sequence, we must click on the “2” shapes button just at the lower left of the curve display. This is what you should see, a beautiful triangle wave:

Wave 1 shape 2Put back some motion in there by setting the motion parameter to 1/4 and we should here a rich pulsating timbre that pulses every quarter note:

Now, for the fun part. Lets modify the second shape of Wave 1. Click and drag the existing shape curve buttons and use the “Add Point” / “Delete Point” features to create a shape that ressembles this:

Custom wave shape

To listen to this wave shape, we must set the start to 50% and turn off motion:

Put back some motion, for instance at 2/1, and we have a nice bright growling bass when played on low notes:

You can now play around with all this and then join us for the next tutorial.

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Oberon discounts for LeSpace and Noxious owners

If you are a current owner of our LeSpace or Noxious Rack Extensions for Propellerhead Software​’s Reason and would like to get your hands on our latest Oberon Synthesizer, we now offer discounts!
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