Filtering in the realm of music production is by no means a new thing. Nevertheless, it’s one of the most used techniques regarding audio processing. These days we have an abundance of filter types ranging from simple low and high cut, all the way up to crazy sounding formant filters. In the next tutorial, we will speak about a new plugin called Mobius Filter designed by iZotope.


Mobius Filter by iZotope


The goal of Mobius Filter is to replicate the “Shepard effect”. Now, the “Shepard effect” or the “Shepard tone” is the sound that keeps rising or falling (depending on what direction it moves). In its essence, it is an auditory illusion of the tone that continuously runs, either up or down in pitch. What Mobius Filter is centered around is this idea of continuous movement. After a short introduction, let us move to a practical explanation of its user parameters accompanied with some audio examples.

As usual, I have made a simple chord progression in SoundBridge: DAW by using the Rhodes piano. Let’s check how it sounds unaffected.


~Rhodes Piano Sequence – Unprocessed


Now we will add a fresh instance of the Mobius Filter on the Rhodes piano effect rack channel within the SoundBridge: DAW.



The interface


Upon opening the Mobius Filter we can see quite a simple and straightforward interface, yet this doesn’t mean that this plugin cannot deliver high-quality sound. As you can see, the upper part of the interface is divided into two section. The first, when double-clicked, will turn to visualizer which is representing the sound waves multiplying as you increase the speed of the movement. The lower section is reserved for the X/Y pad which is controlled by the ring icon, and it sweeps between cutoff and resonance frequency of the filter.


Filter type, Movement, Host Tempo, Stereo Spreader


Moving forward, on the lower left part of the interface, we see the filter type. There are two filter types, “Phaker” and “Peak”. What’s more, the second one gives a  kind of more harsher (resonant) sound. Right from that, we can see a section reserved for movement. You can pause the movement by clicking on the first button. Also, you can change the direction of the filter movement. Furthermore we can enable or disable host tempo which directly affects the speed slider which we see below. Lastly, there is a section on the far right which contains sliders for Dry/Wet mix and the stereo spreader.


Audio Examples


After a brief description of the Mobius, Filter parameters let’s move further audio examples. In the next example, I will first automate the X/Y section with filter type set in “Phaker” mode. Also I’ll disable the “Host Sync” to automate the speed slider.


~Rhodes Piano Sequence – Mobius Filter/Phaker mode



In this case, I have chosen the Rhodes Piano chord progression to demonstrate the effect of the Mobius filter. However, you can apply this plugin to many different audio sources, so I strongly advise you to experiment with it.