RSPhaseShifter — High Fidelity Phase Rotator

Great Sounding Alignment, Made Easy


RSPhaseShifter :: Cross–platform Plug–in

The only official digital implementation of Roger Schult/German Audio Lab’s Phase Shifter W2324 pure analog hardware.

Price: $99

Analog Soul, Digital Heart

Creating a very high fidelity, phase shifted version of the input, RSPhaseShifter provides a fast, convenient and musical means of aligning individual mix elements for best subjective result. RSPhaseShifter is great for any situation where you need to creatively control tonality, power spectrum and harmonic content through phase manipulation. Post–production, stem mastering, outboard gear compensation, film re–recording, “live” production, sound reinforcement, along with content creation for gaming and VR all benefit from having RSPhaseShifter on hand.

Old Skool Values

RSPhaseShifter was created in conjunction with Roger Schult/German Audio Lab, and is a painstaking, 64 bit digital realization of Schult’s trusted Phase Shifter W2324 analog phase rotator hardware. When multiple sources compete rather than complement, RSPhaseShifter should be your choice for a fast, intuitive, easy to use and effective remedy.

Simple Yet Versatile

RSPhaseShifter: a mixer’s secret weapon, both live and in the studio…Whether it’s mix sessions with multiple tracks of one instrument, or alignment of spots and overheads, RSPhaseShifter makes quick work of cancellation issues, bringing back the richness and impact you cannot get from basic delay compensation. Match and optimize the time delay or phase response of a subwoofer in a surround monitoring environment, address fold–down issues or create thick, ultra–wide sounds and phase sweeps by deliberately manipulating phase of one side of a stereo track.


RSPhaseShifter’s analog–style controls are no accident. They’re the same controls found on the tried and true Phase Shifter W2324 hardware, only better. With no added noise, double precision internal processing plus support for AAX and 8x sample rates, RSPhaseShifter is a cost effective addition to any engineer’s toolkit.

Better By Design

As with all Roger Schult by MAAT products, the RSPhaseShifter is hand crafted and precision engineered in California by way of Germany. This is an explicit digital recreation of the analog W2324 topology, not a modeling or simulation algorithm. We copied the functionality of the original hardware without analog’s shortcomings. This tool´s value is more about what it does technically, so we left out stuff like fake transformer color, hum or Johnson Noise. There are lots of colorful plug–ins, we simply provide convenient access to the useful functionality along with a classic API Lunchbox look.

The original W2324 analog degree scale is highly non–linear, due to issues with analog circuitry. The original also has ten tick marks, from 10 to 125°. Freed from the limitations of an analog implementation, we have moved to a true, linear scale and extended the range slightly, something only possible in the digital domain. RSPhaseShifter’s eleven tick marks, in 15° steps, start at 15 and go to 180°; 15; 30; 45; 60; 75; 90; 105; 120; 135; 150; 180°
  • Realtime adjustment of phase angle, resonant frequency, gain
  • MIRROR and FLIP modes speed stereo setting selection
  • δ (DELTA) mode for modifying stereo spread in an MS workflow
  • All standard formats: AU, VST & AAX Mac/Win
  • Optimized internal 64 bit processing for highest fidelity
  • Operates at all standard sample rates, from 44.1 to 384 kHz
  • Compatible with standard OSs; macOS, Windows
  • Low fatigue visual design
  • Compact layout
  • Filter gain range of -5 to + 5 dB via 41 position stepped control
  • Continuously adjustable phase angle between 15° and 180°
  • 3 position switch to extend phase angle from 180° to 360°
  • Bypass position for quick and easy comparison with the uncorrected signal
  • Stepped or continuous rotary control to select frequency range from 16 to 4 kHz


This three position switch is used to select the range of the phase shifter.

Top position:   +180° (180 - 360°)
Center position:   Bypass
Bottom position:   0 - 180°

The center Phase position, the “0” setting or Bypass mode, provides a means to compare the effect of the selected phase shift with the unprocessed, original phase of the source material.


The phase shift is dependent on the selected frequency setting. The Frequency control is either stepped for repeatability or continuous; your choice. Resonant frequency selection is managed by an 13 step ELMA–style control with the following frequencies:

16 Hz  400 Hz
25 Hz  630 Hz
40 Hz  1000 Hz
63 Hz  1600 Hz
100 Hz  2500 Hz
160 Hz  4 kHz
250 Hz

Additional controls include a ±5 dB of gain refinement plus MIRROR, FLIP and δ (DELTA) modes for use during stereo operation.

What’s Your Headache?

For most applications, it makes sense to use RSPhaseShifter on just one channel, rather than on both stereo channels. A common example would be when a stereo pair of ambiance mics suffer from slightly different distances to a localized source. Additional uses include:

  1. You have a DI’d bass track which sounds dry and lifeless. You drop that track into a project so you can re–amp it, and dial up a great re–amped sound. When you try to blend the DI track with the re–amped track, it sounds…awful! Just grab RSPhaseShifter, insert it into the DI’d track, and start off with a low frequency setting. Sweep the phase angle control and fine tune the frequency and…Bang! Suddenly, it sound awesome.
  2. Another scenario would be you have a set of two distorted guitar tracks recorded with different guitars or amps but playing the same riff. They sound nasty because both are modeling–based guitar amp simulations. Just insert the stereo version of the RSPhaseShifter into one of those pair of tracks and play around in Mirror mode, so that both sides of your processing track are ganged. Within seconds, you will find a sweet spot where both guitars blend perfectly, because by sweeping through the phase angle control, you’re applying very complex comb filters which you could not create with other EQ.
  3. Sometimes mixes or stems come in with a stereo panorama that’s simply too wide. The resulting mix is way dense and requires more careful crafting of the soundstage, so you start to narrow individual elements. But wait, as the elements becomes narrower, their timbre suffers…RSPhaseShifter to the rescue! Bring back the grunt and meat while folding down toward mono.
  4. A common situation is you have closely spaced, multi–mic’ed sources, like a snare with top and bottom mics, some instrument with two mics, or an acoustic guitar with a mic and a piezo pickup. Just play around with the RSPhaseShifter on one of the feeds, preferably the one which is closest to the source, such as a piezo feed, and find the sweet spot by feel.
  5. Yet another would be you’ve made a great acoustic stereo recording and have used supporting microphones, such as room, spot or far hall placements. To meld these into your main stereo pair, take your mains as the phase reference, and align one supporting mic after the other with the mains. This is easiest if your supporting sources are panned center and approximately the same level during phase alignment. Afterwards, you can set gain and panning back to taste.
  6. Acoustical issues are often an annoyance at low frequencies. RSPhaseShifter works to…
    • Minimize the influence of standing waves or room modes for a loudspeaker setup in conjunction with one or more subwoofers.
    • Reduce the acoustical energy caused by low frequency cancellation in live sound applications.
    • Acoustically optimize the sound field in studio and live sound environments.

Learn More

Get the most from RSPhaseShifter with these three use case videos…


Watch it directly on YouTube.


Watch it directly on YouTube.


Watch it directly on YouTube.

Thom Wettstein

Thom Wettstein von Mondstein Records zeigt Ihnen, wie Sie die Phasenlage mit dem RSPhaseShifter von MAAT korrigieren…

Sehen Sie es direkt auf YouTube an.

Download — RSPhaseShifter User Manual

The user manual PDF includes production tips and tricks…

Reviews & Testimonials

Олег Ершов (Oleg Yershov) writes in the January 2018 issue of FutureMusic

With the release of RSPhaseShifter, MAAT showed that, in the market for audio plug-ins, there was one more strong player with which it’s impossible to ignore. The quality of their algorithms proved to be extremely high, the design and aesthetics of the instruments do not raise any questions, and the ideas embodied in the products look very complex and, with respect to the past, look far into the future. The cost of RSPhaseShifter is $99, which is quite reasonable given the functionality and possible range of applications.


  • Phase correction up to 360°
  • Zero delay
  • Presence of DELTA (δ) function
  • Possibility of independent stereo operation
  • Absence of automatic phase correction

→ Rating: 8.5 out of 10

Jamie Rhodes-Simpson — audio engineer & cinematographer

“Excellent customer service and excellent plugins — it’s really nice to be dealing with a real human being! …for a long while now I’ve been intrigued by the various recording techniques used for classical/orchestra and choirs…I had (a) stereo pair at the rear of the hall and a four mic array halfway down; two cardioid and two omnis on the outsides. I got to musing about the phase difference between the two cardioids and the two omnis on the same bar. So I did some maths and worked out the wavelength between the mics that was most likely to be an issue and then used RSPhaseShifter to mess with just that frequency and it was like lifting a veil. The sound before was fine, but it was just that bit better with the plugin enabled.” See What’s Your Headache item #4 above…

Alberto Rizzo Schettino, Fundamentals of Mixing || MAAT Digital Core Plug-ins

Schettino has created a comprehensive look at many of our products and how they fit together

Andy Rogulich — studio owner, engineer & Mix Magazine’s World Class Studio of 2017

“(I) purchased RSPhaseShifter right after I downloaded the trial version because I was so impressed with the results. I used it on a project…that had vocal added to electronic music and found the Delta feature to be such a quick way of determining what effects I was adding with RS PhaseShifter in the mirror mode. Really a great new useful tool for mastering to help enhance the dynamics of a recording. Looking forward to the next MAAT tool!”

Geo Hanlin a.k.a. “sonicdefault” — studio owner, engineer & musician

“Congratulations…MAAT team with this excellent plugin! I've been working with RSPS and think it sounds incredible.
For years I’ve wanted a phase tool like this which allowed a continuous range, yet sound natural. I found most of the available products had various limitations, or didn’t retain adequate transparency. It was most important to me primarily with acoustic sourced material such as acoustic guitars. I think I can finally achieve what I've been wanting with RSPS…”

Dr. Heinrich Hohl — indy engineer

“RSPhaseShifter is…very helpful and I don't know of any other audio plugin that could perform the same tasks.”

Tim Teissen — musician & educator

“Of all the plugins I’m using in my DAW, I can imagine no other plugin that is able to fix phase issues like (RSPhaseShifter).”

Click here to read the review.

Kieran Kenderessy — engineer & producer

“(RSPhaseShifter) isn’t always needed, but when it is, it’s a lifesaver…couldn’t mix without it now :)”


A review by Dirk Wannemacher on gave RSPhaseShifter four and a half stars out of five. We lost a half star for sticking to analog–style controls, just like the real thing! ;)

From the review…

The MAAT plug–in is sonically neutral. I could not perceive color or change other than the intended settings. The important transients also pass…without damage. The plug–in sound is on a level with the hardware modules from Roger Schult’s workshop. Nothing is colored. The module does exactly what the name says.”

The MAAT RSPhaseShifter can be used to correct phase errors. Through targeted use on individual tracks, the low end of a mix can be tidied up without pressure being lost, or the highs opened and broadened, (all) without sacrificing mono compatibility. Depending on the audio material and settings, the effect can be subtle to crass. The RSPhaseShifter can, in many cases, provide necessary icing on the cake, to make a good mix an excellent mix.”

→ Rating: 4.5 out of 5


  • Versatile
  • Outstanding sound
  • Detailed operation
  • No coloration of the audio
  • Very good price/performance ratio


  • No graphical tool to find the right angle
Meanwhile, on GearSpace…

— Here’s a couple of RSPhaseShifter reviews.

— In another thread, wagz asked:
“I was considering buying RSPhaseShifter. But, I already have MAutoAlign. Have you compared these two plugins, by any chance?”
Karloff70 said:
“Different thing. I also have MAutoAlign, but it hasn’t come in very useful after initial excitement. Comes up with a different guess each time you roll the dice. No dice involved in the RSPhaseShifter, just frequency specific, manually dialled in goodness.”
Robo said:
“Hi wagz, I haven’t used the MAutoAlign I’m afraid but I agree with everyone here, the RSPhaseShifter is one of those plugs that takes care of your audio, extremely transparent and you get out exactly what you put in (except for the phase changes of course!)”

Reviewers! Want to add your voiceover to the mix?

Head to our Contact page and give a shout…
We’d love to hear what you think about RSPS!

Speeds & Feeds

Downloads, Features & Specifications

Stay Current

Looking for the latest version of your software? Just download and install the demo! The installer will update everything and your license will take over when you next use the product.


  • Analog–style phase shifting
  • Mono & stereo operation
  • double precision, 64 bit DSP


  • AAX Native (Pro Tools 10.3.10 and newer), AU, VST 2, VST 3
  • Sample rates from 44.1 to 384 kHz




  • macOS 10.9 and newer, Universal Binary 2, 64 bit only
  • Windows 7 and newer, 32 & 64 bit


Price: $99