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MAAT RSPhaseShifter review by

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Roger Schult has been supplying the audio community with his high-quality and very precise, but above all, analogue tools for several years now. Now we have the first virtual version of one of his products, which he developed together with MAAT. If you look at who's behind it, you'll come across, among others, Friedemann Tischmeyer, who is not entirely unknown in the studio scene.


Like the Hardware

Outwardly, the developers of MAAT have kept the design of the plug-in close to the hardware. Since the hardware is a mono module for the API Series 500 system and the MAAT is also in a stereo and a dual-mono version, it looks like two modules side by side. Whereby, depending on the selected operating mode, one of the modules consists of only one dummy plate. The controls of the original have been adopted, but with extended value range, where appropriate. All settings are made directly with the displayed controls, there are no menus. Pressing on the MAAT logo, only a window appears, in which the user manual and various links in the network can be accessed.

The developers have decided not to rebuild the hardware PhaseShifter by physical modelling, but they have created a digital switching diagram, from which then an algorithm was developed.


Overall, there are three key controls on the PhaseShifter plug-in. Using the top rotary control, the output level of the PhaseShifter is determined in a range of -5 dB to +5 dB. This allows us to compensate for level changes that may occur due to the phase shift.

Underneath is the rotary knob of the phase angle, which can be adjusted between 15 ° and 180 °. With the switch directly below this range can be extended by 180 ° up to 360 °. The middle position of this switch corresponds, as with the hardware version, to a bypass of the entire module.

The third large control is a rotary switch that adjusts the frequency range the phase delay is acting on. Here are 13 frequencies between 16 Hz and 4 kHz to choose from. As with the hardware version, this is actually a rotary switch and not a potentiometer. The advantage of the plug-in is that with pressed shift-key also every intermediate position is possible. The filter used works with a slope of 6 dB per octave.


The MAAT plug-in is tonally neutral. I could not perceive any colour or change other than the intended settings. The important transients pass through the phase shifter unscathed. Sonically, the plug-in is on par with the hardware modules from Roger Schult's workshop. Nothing is dyed or glossed over. The module does exactly what the name says.


Using the MAAT RS phase shifter, phase errors can be reliably eliminated. The targeted use on individual tracks, the low end of a mixture can be cleaned up, without losing pressure or the heights are opened and made wider, so without sacrificing the mono compatibility. Depending on the audio and settings, the effect may appear subtle or crass. In many cases, the PhaseShifter can deliver the icing on the cake that sets a good one apart from a very good one.


  • Versatile.
  • Excellent sound.
  • Clear operation.
  • No colouring of the audio material.
  • Very good price/performance ratio.


  • No graphical tool to find the right angle.

Overall Score:


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