Review – Nitroflex 1.92 by Synthblitz Audio

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Synthblitz Audios’ Nitroflex is a five-oscillator synthesizer VST plugin for Windows. We take a close-up look at the instrument in this review.

by Rob Mitchell, May 2014


Synthblitz Audio is the software developer of Deep One, DNX-03, and Spazial.  Nitroflex is their five-oscillator synthesizer VST plugin for Windows.  It is mainly a subtractive synth in nature, but it also has some FM qualities included. I haven’t heard if there eventually will be a Mac version, but for now it is only available for the PC. There are no 64-bit or standalone versions available.

On the Synthblitz website, they mention their plugin is aimed at House music, though I don’t think a synthesizer plugin is ever just for one style. On the other hand, it ships with over 1,000 presets, and a good amount of those are trance/house music oriented. 



For each of the first four oscillators, there are controls for octave, semitone, detune, and pulse-width modulation. Nitroflex has three banks of waveforms to load in, and there are 65 in each bank, giving you a choice of 195 for each oscillator.  Using the red numerical display on the left side, you just click and drag up or down to select a waveform. To switch between the three banks, you click on the one of the three LEDs next to that numerical display. In addition, if you switch an oscillator from “Internal Waveform” mode to the “Expansion Wavetable” mode, you then have 64 wavetables you can choose from.

There is a fifth oscillator in the lower right of the display. The only waveform available for it is a saw, but it could be used to harmonize in higher ranges with the other oscillators. You could also tune it lower and use it as a sub-oscillator. This oscillator includes a noise generator as well. When you change its tuning, i.e. semitone or other amount, it doesn’t show it in the display. The other four oscillators work normally, and you can see the amount changing in the display when you adjust their controls.

There is a simple type of FM synthesis included in Nitroflex. You can use the first oscillator to modulate the second oscillator, and you can use oscillator two to modulate oscillator three. They’ve also added an FM tune control. It seems to be some sort of phase adjustment, but I’m not 100% sure since it’s not mentioned in the manual. 

They have also included unison, and it can be set to use seven voices. One thing that is a little confusing is that there is no readout for unison on the display. In other words, you don’t know how many voices it is set to. Also, the manual shows a different screenshot for the unison control section. I like the manual’s version better, as at least I can tell how many voices there are when I turn the knob. I didn’t see a way to control detune or the amount of spread for unison.



Nitroflex has two filters included. For each of the two filters, you have a choice of Lowpass, Highpass, or Bandpass, pow, and Soft. The last two modes, “pow” and “Soft”, aren’t mentioned in the manual. I contacted Synthblitz about this, and they explained “pow” and “Soft” are two additional lowpass filter modes. I tried them out myself, and the “pow” setting seems to accentuate the resonance more than the “Soft” setting. 

The filters can be set to Parallel or Serial mode. Each filter has its own cutoff control, but there is just one resonance control for both. There is a Filter Pan control as well, and turning it from left to right will adjust the level of the two filters.

One strange thing I noticed was when I tried to use the MIDI Learn on the filter controls. Normally, you just have to right-click on a control in Nitroflex, and it will give you the option to Learn or Unlearn. This works fine, and is simple to use. For the Filter section however, after right-clicking on knob, it would flash all different colors around that same control. I would think all the controls would act the same way, but only the filter controls function in this manner.


LFOs, Envelopes, and Effects

Nitroflex has three LFOs, and they can be assigned to many different targets. Each LFO has a good number of waveform choices, and includes controls for Speed, Depth, Phase, and Delay attack. To the right of the Phase control is where you can select a destination for the selected LFO. Multiple destinations can be selected for each LFO, including Pitch, Filter1, Filter2, Filter 1+2, FM, PWM, FM/PWM, Oscillator volume, and Noise amount.

There are three envelopes available; one for amplitude and two envelopes that you can assign to various targets for modulation. For Mod Env1, the destinations include Cutoff1, Cutoff2, Cutoff 1+2. For Mod Env2, you can choose from Pitch, Resonance, FM, PWM, Noise, and a few others.

The effects include Reverb, Delay, Vibrato, Phaser, Chorus, EQ, and Distortion. One thing that’s a bit different than most synth plugins is that the Delay and Vibrato are separated from the other effects. They are located on the right side of the main panel, while the other effects are together in the LCD section. They do mention this in the manual, and state that it is for added speed and convenience while designing presets. 

You can turn off all the effects at once from the Options menu. This is handy, but there’s no way to turn them all back on again. I’d prefer an effects bypass button instead. Maybe this could be added for v2.0?



You can setup the Arp/Gate to use up to 32 steps, and it can be set to modulate the filters. You can target either of the two filters, or both at the same time. It’s possible to save your own patterns, and there are a few presets they’ve included that you can load up.

There’s a smoothing control included, and there are many different BPM settings to choose from. I’d like the arpeggiator to have a swing setting added, and more modulation destinations, such as resonance, filter pan, noise and FM amount. 


Edit and Expansion

In the Edit section, you can manipulate the waveforms in different ways. It’s possible to draw in your own waveform, or use a generator to create one randomly. There are controls to invert the waveform, change its volume, and adjust its phase. 

In this same section, an oscillator’s mode can be switched so it can use one of the 64 expansion wavetables. Among the choices are TechSquare, Pure Triangle, Formant Square, Piano, Organ, UHF1, Electric Piano, and many others.

Using the mathematical controls, you can further manipulate your waveform. Add, Subtract and Multiply functions are included, which basically combine waveforms together in a multitude of ways.  After manipulating a waveform around to my liking, one feature I’d like added is the ability to easily copy that waveform to another oscillator.

On the Expansion, page, you can select four different wavetables presets, and they will combine together to make a new wavetable.  You can see the resulting shape of the wavetable on the right side of the screen.

It’s possible to have a wavetable made up from as many as sixteen different waveforms. One way you can use this is by adding all the oscillators (set it to “1+2+3+4” on the Edit page) and you’ll have a combination of the waveforms from the four oscillators. Waveforms can also be loaded in to Nitroflex for editing, saved to disk, and then loaded up later whenever you’d like.

Altogether, there are around 400 wavetables and single cycle waveforms to choose from. You can get tons of different sounds by combining them together in different ways.



Nitroflex has a good sound and is easy to use. I do have to mention the manual, as it could use an updating. Some parts of it don’t match with what you see on the display of the plugin, such as the last two filter types that I mentioned before. The manual is for version 1.0, while the synth plugin is actually up to version 1.92, so there are differences between them.

There are some good presets included, but many others didn’t really jump out at me. Also, I thought the names of many presets could be improved. For instance, around thirty or forty of them have the name BASSsynthx, where the x is just a different letter or number. Deep Kitx is another huge group of them named a similar way. It’s difficult to remember a synth preset you want to load in again later if its name is almost exactly like thirty others.

I’d like to hear some presets made by 3rd party preset designers, as it would be interesting to see what they could come up with. It does have a lot of possibilities with the combination of its large amount of waveforms, five oscillators, unison, effects, and FM thrown in.

One thing I’d like added is a way to get a certain knob back to its default value. Many other synth plugins will let you either double-click on a knob, or use control-click (or alt-click) to reset them. Also, like I mentioned before, any change to controls should be shown numerically in the LCD display.

Even though there are a few things that still need fixing up (and added, such as oscillator sync) I can say that it is a powerful synth with a good price. Until the manual is updated, you will have to figure out a few things on your own. Also, as I mentioned before, there’s no Mac version and no 64-bit version for Windows. I passed along a few ideas to the programmer, and he was quick to add them to Nitroflex. Now that’s good support!  The PWM was improved, and the ability to initialize/reset a preset was fixed up as well.

The manual will hopefully be updated at some point, as it would make it much easier to use.  The synth itself can be improved here and there, but it’s definitely worth checking out. Nitroflex retails for 49 EUR. At the time I wrote this review, it was on sale at the bargain price of 29 EUR, which is about $40.00 USD. 

You can download the demo version of Nitroflex from their website here:

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