Unfiltered Audio’s newest plugin, Fault, has just been released, and it comes with high expectations.  Plugin Alliance’s website (where you can download a full functional 14-day trial version or purchase the plugin outright) boasts Fault as a “new kind of effect,” a “pitch/mod tool [that] soothes the savage sound,” and the creator of “spectral modulation mayhem.”  But what do those catchy phrases really mean? I dug into the new plugin to find out.

Fault is a stereo spectral shifter.  To oversimplify things to the max, that means that it pitches your original material up or down and lets you mix that back in with the original sound.  You can then modify the effect further with feedback, delay, filters, and coolest of all, FM synthesis.  

While Fault was originally designed with music applications in mind (and subsequently has a ton of great features for syncing your delays and modulation to your session’s tempo), I thought it also had great potential for the sound design world.  So, I gave it a whirl and attempted to create some interesting dragon vocals.  

The Technical

There are five main components to Fault: pitch or frequency shift, feedback, delay, filters, and modulation.  

Pitch and Frequency Shift

Fault’s main function is as a spectral shifter.  All other components to the plugin allow you to affect the output of the spectral shifter.  They have divided this main function into two options: pitch shift or frequency shift.  The pitch shift section should be used for seamless harmonic shifting (ideal for music).  The slightly more complex frequency shift module can be used to achieve a more raucous result that sounds grittier and more metallic.  

When using the pitch shift module, you can choose to shift the left and right channels separately or link them together.  You may also choose to activate the quantize button which will only allow you to pitch by semitone values.  This is ideal for keeping musical elements in the correct key or creating chordal structures.  The maximum shift amount is one octave.

The frequency shift module boasts more complex controls.  Again, you can choose to shift the left and right channels separately or link them together.  But, the addition of a mult knob allows you to multiply this increment up to ten times, giving you +/- 5,000 Hz to work with.  Additionally, you can spread the effect and even modulate it with a designated oscillator using the FM frequency and FM depth knobs.  

Feedback Matrix

The feedback module of Fault gives you the option to add feedback to the output of the shifter module or the delay module.  For each, you may choose to add feedback separately to the left or right channels, to link them, and/or to add cross-feedback wherein the feedback is sent from the right channel to the left and vice versa.  Cross-feedback can quickly get out of control, so the creators at Unfiltered Audio recommend using it in small doses. When using feedback as a design tool, you may want to click the stabilize button, which prevents runaway feedback oscillations.  Or, maybe not if you want a really wild effect!


The delay module is very straightforward.  It allows you to add delay in differing amounts to your left and right channels or to link the two together.  Clicking the sync button will lock your delays to the host tempo and allow you to adjust it using note value increments rather than milliseconds.

Feedback Filter

Again, this module is very easy to use.  You have the option to add a high-pass or low-pass filter to the output of the feedback module.  If you choose Filter All, the filter will instead be applied to the summed output rather than just the feedback output.


Now for the fun part! So far, Fault has been incredibly straight-forward (which is not to say boring).  Its simplicity in its main functions makes it amazingly intuitive while still harnessing some very potent processing power.  But, the modulation section is where things start to get really interesting.  As a sound designer, this is where I found the greatest potential for creating a unique effect.  

First, you need to show the modulation section by clicking on the modulation button at the bottom left of the plugin.  This will reveal modulators which you can digitally patch into other sections of Fault. You’ll notice now that all controls in the entire plugin have small circles at the bottom. These are their inputs.  Each signal generator in the modulation section has outputs at the top (and knobs directly below those outputs to let you choose how much of the signal to send).  You can create digital patches between these outputs and inputs to affect parameters of any of the modules mentioned above.  Even the controls within the modulators have inputs, so they too can be modulated by a new signal.  To create a digital patch, simply click and drag from an output to an input.  To remove the patch, click and drag one end and release it when unattached.

Modulation Options

There are several modulator types to choose from.   First, there are the standard LFO (low-frequency oscillation) options: sine, saw, triangle, and square.  As you may know, low-frequency oscillation is when a signal of 20 Hz or less is used to create a rhythmic pulse or sweep.   Common examples of this are vibrato, tremolo, and phasing.  

The input follower modulator lets you side-chain parameters to the incoming audio.

The macro modulator lets you output values to multiples parameters so you can make sweeping changes with the turn of a single knob.

The sample and hold noise modulator chooses random values at the chosen frequency rate.

The Artistic

One of the most fun ways to use a new plugin for sound design is to create other-worldly vocals, whether that's aliens (for which we blogged about using Dehumanizer) or monsters (for which we used Voxpat).  So, I decided that the best way to compare Fault to our other powerhouse plugins would be to do something similar.  And, I was in luck: this week I needed dragon vocals! 

I started with a couple of the vocalizations we custom recorded during our monster vocal session.  For me, there are tons of options in my library for straight-up dragon roars.  You can always layer in a processed animal roar with a few unexpected textures (metal wronks, anyone?) to beef it up.  But, I was missing a really excellent ruckle.  What is a ruckle, you ask?  It is a word that us editors use to describe that deep back-of-the-throat clicking sound that makes monsters sound incredibly creepy.  To me, nothing says "dragon" like a good ruckle.  

Here are the original samples that I used:

With these sounds in mind, I set out to create a good ruckle preset. I ignored the pitch shift module and went for the frequency shifter because I knew that I wanted something more dramatic.  I set the base frequency shift amount to around -250 Hz (to beef up the vocal) and then panned and spread it.  

Since all vocal sound effects should be in mono rather than stereo, I linked the left and right channels in the delay and feedback modules, then added around 50 ms of delay to the sound.  I wanted enough to create a good effect, but not so much that if we were close to the dragon, it would sound like there was too much "room" on him.  I also added opposing amounts of feedback to the shifter and delay modules and adjusted the dry/wet mix to around 75%.  Although Fault can sound pretty cool with a 50/50 mix, I wanted a more extreme change with this preset.  

Finally, once I was happy with the basic quality of the sound, I dug into the modulation section.  I added a square wave LFO to module the frequency shifter itself.  This is what actually achieved the meat of the  ruckle effect.  Hear those oscillating elements in the samples below?  That's the square wave in action.  Then, I added an additional modulator and set it to sample and hold noise.  This, I used to module the width of the square wave LFO modulator.  Cool, right?  Take a listen to what the growls and hisses sounded like after I processed them:  

I'm including a download link to my custom dragon ruckle preset for Fault.  I would definitely suggest downloading the free trial of this plugin and at least clicking through their factory presets, which are pretty gnarly!  For $99, in my opinion, this plugin is a steal.  


One Bug

While testing this plugin, I uncovered a bug.  When using the Audio Suite version, the rendered version of your audio does not match the preview.  It seems that the oscillators default to a lower frequency.  However, when using it as an insert and either bouncing to disk or recording to a new track, the output of the plugin is correct.  The programmers at Unfiltered Audio have been alerted of the issue and it is now in their troubleshooting queue.  I'll update this post when the issue has been resolved, but for the moment, I would suggest using Fault as an insert.