Review – Strobe2 by FXpansion


Fxpansion’s Strobe2 has some enhanced features hidden within it’s slick and intuitive interface. Our reviewer takes it for spin and checks it out in detail.


by Rob Mitchell, July 2016


This is the first product by Fxpansion that I’ve ever evaluated and I have to admit that I am late to the party. Fxpansion was founded in 1999, and ever since then they’ve produced many acclaimed products such as Synth Squad, Geist, Tremor and BFD3. I have no excuse as to why it took me this long to wake up and smell the coffee, but this one really sparked my interest. Strobe2 is their latest offering, and it happens to be a sequel that many people have been waiting for. It is a virtual analog polyphonic softsynth that has over 900 presets, features powerful modulation, hard-sync, an arpeggiator, preset morphing, and a scalable display.

After downloading and running the installation for Strobe2, you get the chance to change the directory for the install. After you finish the install, it needs to be authorized. It uses a serial number which can be used for the authorization on the computer if it is online, or you can use a separate computer if you prefer to keep your DAW offline.

If you run the standalone version and authorize it, it is then all set for any other version you have installed as well. For this review, I used a PC with 64-bit Windows 8.1, and have Sonar X3 Producer installed as my DAW. The system requirements for the PC are Windows 7 (or later), Core 2 Duo – 2 Ghz, and one gigabyte of RAM. They do however recommend an i5 CPU and four gigabytes of RAM. For the Mac, you’ll need OS X 10.8.5 (or later), Core 2 Duo – 2 Ghz, and one gigabyte of RAM. It is available in VST, AU, AAX64, and RTAS formats.


The Browser

After it was up and running in my DAW, I was presented with its main display. Along the top is a section I will get to later, as I believe it would be helpful to go over the main parts of the synth first. On the left is the browser, which can be hidden by clicking on the “Browser” menu item right above it. Whenever you want it back, just click it again. You’re able to browse by type (lead, bass, chord, etc.) and/or artist, and go through the presets one at a time by using the left/right arrows. A handy search field is here, and presets can also be marked as favorites by clicking the star to the right of the preset name. In contrast, if you don’t like a certain preset, right-click on the preset name and you can hide it from view. In addition, you can sort the presets by type, name, or the last saved date. 

The first preset that is loaded by default is a plain INIT type, which lets you take the wheel and design from that point on. When you get to the point where you’ve designed your own preset and saved it, you can find it again by clicking the “Library” button. Then you just select “User” in the dropdown menu that appears. You may however just want to skim through the factory presets, and that’s exactly what I did. There is a large variety of quality patches here which make good use of Strobe2’s built-in functions and effects.


Oscillators, Filter, and Amplifier

Most synth plugins these days have two or more oscillators to work with. Strobe2 works in a different way than many of them on the market, as it has just one primary oscillator. Before you say “Wait a minute, what do you mean only one oscillator?!”. Don’t worry – I will explain how it works momentarily.

In the “Main Oscillator” section of the display, there are many controls. Besides the normal tuning controls found here, there are sliders to adjust the amount of modulation (positive or negative values) from the keyboard, LFO, and modulation envelope. It has square and sawtooth waveforms you can use, with sliders for each to change their levels. In other words, you’re able to have both of them play at the same time if you’d like. The Sync function works by adjusting the oscillator’s pitch while syncing it up to the Pitch and Fine tune settings. The “Tone” control is a keyboard tracking EQ you can adjust, which can help to adjust the frequencies the way you’d like before they arrive at the filter.

Now we get to the Stack function. This can definitely thicken up the oscillator’s sound, as it makes copies of itself (up to five) and you can specify the amount of detune between them all. Unison is also on board, and up to 32 unison voices can be used. For the Square waveform, there is a PWM knob for directly adjusting the pulse width. Sliders are included below the PWM control (just like for the pitch) which control the amount of modulation for the pulse width from the keyboard, LFO, and modulation envelope. I will get to more details on these and other modulation sources later in the review.

Besides the Main Oscillator, there is a Sub-Oscillator and a Noise generator. The Sub-Oscillator has four waveforms you’re able to use (sine, triangle, saw, and square), and their levels are adjusted with individual sliders. Besides the settings for the levels, each waveform can also be set to one of four octave settings: 0, -1, -2 and -3 below the main oscillator’s pitch.  The square waveform also has its own PWM control. The Waveshaping control affects all waveforms of the Sub-Oscillator, and the Tone control works in the same way as that of the main oscillator. The Noise generator produces white noise, has a slider for its level, and has its own Tone control as well.

To the right of the oscillator is the VCF (voltage controlled filter). It has the usual cutoff and resonance controls, and they’ve added a Drive control, which lets you dial in a saturated/driven tone in the filter. Speaking of the filter, there are 22 different filter modes to choose from. There are some standard ones here, such as 2 or 4 pole low-pass, high-pass, and band-pass, plus there are a couple that are not quite so common: peak and notch. Many of the other filter settings use “pole-mixing”, which combine two different type of filtering into one. You can see their effective shapes by using Strobe2’s built-in Visualizer Scope. This scope also works with many other areas of the synth, letting you see waveforms of the oscillators, envelope and LFO shapes, and other information that is handy to have whenever it’s needed. The filter’s cutoff can be also be affected by three sliders which (like other areas of the synth) control the amount of modulation from the keyboard, LFO, and modulation envelope. The “Leak” control lets in an amount of unfiltered audio to mix with the filters output. This basically simulates what’s known as a bleeding filter circuit.

The last section in the upper-row of controls is the V.C.A. (voltage controlled amplifier). By adjusting the Amp and Volume sliders in different ways, you can get either a nice overdriven type of sound or a cleaner/softer sound from it. They’ve added an “Analog” control, which adds a classic noisy character to the audio. The “Pan” slider has no surprises hidden away, and as expected, it lets you adjust the panning from left to right.


LFO and Ramp Generator

In the next row of controls, there is the Dual LFO section of the synth. It is named “Dual” as it really has two that run at once. There’s the regular one, plus a sub-LFO, which uses a clock division from the first LFO for its own timing. There are 21 shapes available for either of the two LFOs, and they can be modulated by the Trans-Mod system, which I will get to later. Strobe 2’s Dual LFO can run in a polyphonic or monophonic mode.

The main LFO is routed to the filter cutoff, oscillator pitch, and PWM. The sliders I mentioned earlier control the amount for each of those. The sub-LFO (and the main LFO) can be set to modulate other parts of the synth, but the sub-LFO isn’t hardwired to targets in the way that the main LFO is. Rate, Swing, and LFO phase slider controls are here. You can sync to the host and set the LFO section to run in polyphonic mode (per-voice) or monophonically. The LFO’s Gate Mode control adjusts the way it operates, and lets you choose from 6 different settings. For example, if you’d like a free-running setting, you’d use the “Song” mode, while the “Poly” mode is a polyphonic key reset mode. Other modes include Poly On, Mono, Ramp, and ModEnv.

Another handy feature in Strobe2 is its Ramp generator. It acts basically like an inverted envelope with controls to adjust Delay, Rise, and Scale. It works best with the Trans-Mod (yeah, yeah … I’m getting to that …), but it can also be used as a gate for other modulators within Strobe2. The “Delay” setting is the amount of time it takes before the “Rise” segment begins. Changing the Rise amount adjusts the amount of time it takes to go from 0 to 1, which can be thought of as a decay amount. The “Scale” control multiplies the amounts you’ve set with Delay and Rise. Other controls included Sync and Loop. “Sync”, as usual, denotes host synchronization vs. an explicit time setting.  Enabling “Loop” will keep repeating the “Rise” section of the Ramp generator. It can also be setup with the same gate settings that the LFO uses; Poly, PolyOn, Mono, ModEnv, LFO, and Song.  


Additional Scope Settings and Envelopes

At the bottom of the Scope display are buttons to switch to other features that the Scope display can provide. These include Euclid, Curv1, Curv2, Zone1, and Zone2. “Euclid” is a type of X/Y pad with many controls to adjust modulation in various ways. Using the Tran-Mod settings, you can get some very complex modulation happening. An external X/Y pad controller can be used to control it as well.

Curv1 and Curv2 are Curve Processors which can be used with sources of modulation. They have controls to let you adjust the slew (a smoothing amount) and the number of steps in the X and Y axis of the curve itself. The steps can be altered by clicking and dragging inside the display.

Using the “Zone” feature, you’re able to click inside the display and draw in the shape of key tracking you’re after.  The two Zones can be tied to various sources of modulation.

Next to the Scope are the Modulation and Amplitude envelopes. These work the way you’d expect with typical ADSR envelope controls, but they have a few tricks up their sleeves. Each can be used to modulate more than just filter cutoff and the amp envelope. Actually, either one can used with nearly any synth setting you’d like. In addition, both envelopes also feature the same gate settings I had mentioned earlier in the review: Poly, PolyOn, Mono, ModEnv, LFO, and Song.  Other controls included are Sync, Loop, and Linear. Once again, “Sync” plays its usual role. Enabling “Loop” repeats the envelope (the attack and decay stages), so it can be used as a type of alternate LFO. Enabling the “Linear” button adjusts the envelopes so they will have a linear response, otherwise they will work exponentially.



Now (as promised) I will finally get to that Trans-Mod section of Strobe2 to which I referred earlier. It is a bit like a modulation matrix in which you can choose from many different of modulation sources. Sixteen slots are included, and each can be loaded from a separate source. The source you pick loads in the top section of the slot you’ve chosen, and the lower part of the slot is for the scalar menu. This basically lets you set it up so that what you pick will affect the target you’ve chosen by multiplying the source output in some fashion. For instance, you might use the LFO to adjust the amount of filter cutoff, and you might want to use the mod wheel as the scalar to adjust the amount.

Unlike a regular modulation matrix in which you would use numbers in some sort of a table configuration or sliders to adjust the amounts, the Trans-Mod is much more visual in nature. First, you select whichever source you want in one of the slots. Then you navigate to a control on the synth that you want it to modulate, such as filter cutoff. When you click inside the outer ring of the cutoff control, you then drag around in the ring with the mouse, and it dials in an amount of modulation. It is easy to use, as you can see a colored ring appear as you drag with the mouse. I used this to assign the Euclid feature as a source, and set it to affect the cutoff. If you’d like the Euclid to affect yet another target, you just go that other one you have in mind, and click/drag again to set it. Even though there are “only” sixteen slots (which is actually quite adequate), you can have nearly unlimited targets for each slot. It works basically the same way with modulation targets that use sliders, too. The visual feedback of the modulation setting you’ve made makes it easier to remember how those same modulations were setup in the first place.


Arpeggiator and Effects

To get to the Arpeggiator page, you click on its tab towards the top of the display. Actually, it also has a step sequencer within it that lets you create a rhythmic sequence of modulation. The sequencer has a graphic display in which you can draw in a series of bars at varied heights with the mouse, and these affect the amount of modulation. In the Trans-Mod system, you’d add either StepSeq+ or StepSeq +/-, and then select a destination for it to modulate. The sequence length can use up to 32 steps, and the “Slew” control adjusts the amount of lag/glide between step values to be used with the Trans-Mod.

The arpeggiator itself has many standard controls, like Rate, Tempo, Mode (Forward, Forward/Reverse, Random, and Manual), and Range (up to 4 octaves). The Priority control will use certain play modes that take into account which notes were played in what order (or how soft or hard the velocity is) to determine how the arpeggiator will operate. Some other controls included are Swing and Gate Time, which are always useful. I don’t know why anyone would not want control over swing in an arpeggiator, and I believe it really should be in every synth plugin in this day and age.  Another handy feature is the Retrigger function; when activated it will restart from the first step of the sequence when a note is played. “Arp Resets Seq” will set it so the sequencer is automatically reset to the first step when the arpeggiator hits its first note. “Seq Resets Arp” will set it so the arpeggiator is automatically reset when the sequencer has its first step.

I won’t go into too much detail about the individual effects, but I did want to give an overview of what is included. The Effects section has two rows with three effect slots in each, and you can load them in whichever order you want. Each of the two rows also has its own mix knob. You’re able to reorder the effects with a simple drag-and-drop, and I really wish every synth plugin had that feature.

The wide range of effects included in Strobe2 are EQs, enhancers, filters, compressors, a noise gate, envelope shaper, delays, reverbs, and distortions.  Some of the modulators include phaser, flanger, formant filter, auto filter, and ring modulation. Many of these effects have built-in presets (thankfully, you can save your own), plus there are on/off buttons for each effect module, and a mix knob as well. If you’ve read any of my other reviews, you might have noticed that I love being able to modulate the effects in a synth in various ways. Good news: the powerful Trans-Mod system can be used to modulate many parts of Strobe2, and that also includes the effects section.


More Goodies

With some synthesizer plugins, there are just so many features that I just can’t cover everything. Strobe2 has a few other features I didn’t fit into other parts of the review, such as the Unit and Snapping modes, Locks, and using the unison with Trans-Mod.

The Unit and Snapping modes let you adjust the way that the coarse tuning and filter cutoff work. With these selections, jumping to harmonic values is possible, instead of using equal-tempered amounts. Speaking of equal-tempered tuning, Strobe2 also supports micro-tuning (using *.TUN files). The Locks function allows you to “lock down” certain parameters so they won’t change when you switch to a different preset. Unison can be used with the Trans-Mod to assign it to many different parts of the synth. The regular way you’d probably use this is with the fine tuning, as it will fatten up the sound. It could also be used with the Pan control to spread out the voices from left to right. Another way you might want to use this is with the filter cutoff, so the cutoff could be slightly different for each voice.

The display can be resized to values ranging from 70% all the way up to 220%, which should work fine no matter what size of monitor you use.

Oversampling can be set from 2 times to 8 times to increase the sound quality even further. This can of course increase the CPU usage, but it’s still a welcome feature.



Strobe2 is very powerful, flexible, and really just sounds great. I especially like the resizable display. The Trans-Mod is one of the easiest to use modulation systems I’ve ever used, and yet it can do almost anything you can think of at the same time. The documentation is spot-on, the synth has loads of superb presets, and it is a blast to use and design sounds with. Depending on how many voices are used, the CPU can get a bit high if it’s set all the way up to 8 times oversampling. I kept it set to the standard 2X most of the time, and it sounded just fine.

Strobe2 retails for $179 USD, and FXpansion offers an upgrade path for owners of their DCAM Synth Squad.

You can get more information on Strobe2 and download a demo version here:






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