The DrMS plug-in is based on Mid/Side processing, a powerful way of manipulating stereo signals that grew out of a recording technique patented by Alan Blumlein in the 1930s. There's really no way to understand the DrMS plug-in without grasping the basics of M/S recording, so let's start with Mid/Side 101.
Very briefly, M/S recording employs two mics in the same spot, the "Mid" mic (typically cardioid) pointing at the sound source and a second figure-eight pattern "Side" mic pointing to the left by ninety degrees so that the two mics are pointing perpendicular to each other. The Mid mic sits exactly in the null spot of the figure-eight Side mic. By recording a source this way, you are capturing a direct image of the sound with the Mid mic and an image of the indirect sounds with the figure-eight Side mic.
 Decoding the signals from the M/S mic pair into a standard L/R stereo image requires a matrix that "adds" the in-phase signals and "subtracts" the out-of-phase signals. To put it in simplified algebraic form (ignoring gain coefficients):
L = M + S; R = M - S.
You can do this on a mixer by patching the Mid signal into a fader panned dead-center and mult'ing (duplicating) the Side signal into two faders panned hard left and right, with the right fader polarity switched. The reverse of this operation can also be accomplished with the same three faders: M = L + R; S = L - R. A handful of consoles, preamps, and outboard gear have M/S matrices built in, and there are several software plug-ins as well. Mastering engineers have been processing signals in the M/S domain for a long while to help them pull out elements in the stereo field and process them separately. It's an exceptionally powerful tool in this setting.
If you found the above explanation a little complex, brace yourself because DrMs is perhaps the most complex and versatile M/S processing tool on the market (and certainly in its price range). The feature set begins with the inputs and outputs of the DrMs plug-in, which both have a switch that tells the plug-in whether to decode or encode. The switch is marked L/R or M/S. If you're feeding a stereo signal into the plug-in, choose L/R and it will encode it into M/S. If you are feeding an M/S signal into the plug-in, you choose M/S and it will leave it alone so that you can use the internal processors to affect that M/S signal. On the outputs, you either choose M/S or L/R to determine whether the plug-in is going to decode the M/S signal into a stereo signal or output a M/S signal. These matrices can be used independently of the rest of the plug-in to do straightforward encoding and decoding.
Once you have a signal into the plug-in, you have four processing sections: Mid, Side, Focus and Field. Mid and Side are easy enough to understand, but Focus and Field are where DrMs parts ways with other M/S processors. To figure these out, we consulted the online manual: "The Focus section feeds original unprocessed mid-information to the side-signal of the final stereo output. The Field section feeds original unprocessed side-information to the mid-signal of the final stereo output." Aha! So DrMs enables you to shape your stereo signal not only by processing the content in the middle separately from the sides, but also by inverting the location of that content. More simply, you can put the mid onto the sides (Focus) and you can put the sides into the middle (Field). Quite literally, you can turn your stereo image completely inside out, or you can send any percentage of the middle or sides to the opposite location.
Let's pause for a second and try to get our heads around this. If you make a reverse print of a photograph, everything on the left is on the right, and everything on the right moves to the left. All images are in reverse, yet the center is still in the center. With stereo audio, we can do this with our pan knobs in a moment. If, however, you fold a photograph in half, tape together the outside edges that are now touching, cut the photo in half along the crease, and then pull it open, you will now have the sides in the middle and the middle on the sides. It's this latter, more complex, manipulation that the Field and Focus controls allow you to do with audio.
If you're not totally confused at this point, perhaps you're ready to digest the fact that each section of the plug-in (Mid, Side, Field, and Focus) contains the following features: level, solo, mute, variable HPF, variable LPF, delay, and polarity reverse. By manipulating the phase, delay and EQ of each of these sections, you can seriously mess with (and mess up!) the stereo image. And if that's not enough, there is a Feedback control that feeds the signal from Focus back into Field and vice versa, with the possibility of creating a full-on feedback loop, but with subtler effects being far more useful and less likely to blow out your monitors.
The possibilities for creating totally unique effects are rather astounding, and DrMs obviously stretches the imagination of what's possible with M/S processing beyond the typical tracking and mastering uses. DrMs seems to be aimed at offering the mixer, beat creator, sound designer, and general sonic-manipulator a totally unique effects device.
The easiest way to get rolling with DrMs is to pull up one of the presets and tweak from there - and thank goodness there are presets to call up and study so you can get a handle on how this unique processor works. Also, the presets allow you to quickly try effects that would require a great deal of knowledge and fuss to set up without the plug-in. The packaged presets include the utilitarian Mid/Side Encoding and Decoding, Gentle Mix Widen, Mono to Stereo, and No Loss Mono Fold Down. These do what you'd expect and make matrixing for this kind of processing a breeze. There are some presets aimed at sculpting a full mix, such as Honey in the Middle, Wide and Airy, High Freq Enhancer, and Vocal Focal. Then there are far more imaginative tools for sculpting stereo sounds, such as Beat This!, Solar Space, Inside Out, Juno Synth Width, Vocalokeeish Stereo & Mono, and Ring Stinger. These presets show off how DrMs's phase, delay and EQ controls can truly manipulate a signal to create spacial and phase-based effects you just don't get with other kinds of processors. These would probably be best used on individual instruments rather than a full mix, proving that DrMs is bringing M/S processing to the creative, expressive side of mixing and sound shaping. With sounds akin to ring modulation, ambient reverbs, and chorus, we wondered if one would be more inclined to use more dedicated plug-ins to achieve these effects,
 but we also had to admit that the parameters one had control over are completely unique, especially when it comes to manipulating the field and focus - or inverting the middle and side images a la our photography experiment above.
Jessica had a perfect opportunity to try out DrMs as part of her mastering chain in an all too common scenario where one of seven tracks on a record suffered from amateur tracking, mixing, and production. The other six songs were recorded and mixed at The Magic Shop in NYC and sounded great, but this seventh track was plagued with phase issues, guitars that dominated the extreme outsides of the mix, and a wimpy vocal. The sound was so mismatched that Jessica suggested to the band that they not include it on the record, but that wasn't an option. To the rescue, Jessica pulled up the DrMs Vocal Focal preset to thicken the lead vocals. Tweaking from there, she rolled off low end on the sides using the HPF to lessen the phasiness of the guitars, and - in a move rarely employed at the mastering stage - fed back some of those guitars to the center (using Field) to create a narrower stereo image with a thicker center that better matched the other six songs on the album. In this case, DrMs pulled its weight as a fix-it tool when major intervention, a heavy hand, and a creative approach were necessary. The band was thrilled - job well done.
On a track Allen was mixing, the drums had a tight, punchy sound recorded in mono at Mavericks Studio in NYC; the bass a brisk and melodic sound; the vocal sent up the middle in mono; and then, oddly, a spacious, stereo synth arpeggio that just sounded too wide in the otherwise narrow mix. There were two possible solutions. Plan A - widen the drums to match the synth. Plan B - narrow the synth to a more mono sound. This was a perfect case to try out DrMs on individual tracks while mixing. Using the Beat This! preset on the drum submix, the mono drums immediately became stereo and sat better with the synth. The punchiness of the drums took a hit, however, and it became clear that the initial decision to track the drums in mono was the right move for this track. Having abandoned Plan A, Allen tried panning the two channels of the synth track to the middle of the mix and found that it just got too dense and lost its sense of movement. Using DrMs brought out a ton of different options for manipulating the stereo image of the synth track. Lowering the sides worked pretty well but robbed the track of some of its overtones and interest, which were clearly out on the sides. Using the Field and Focus controls, however, allowed the image of the sides to be moved toward the center and the center toward the sides. This tweak made the synth sit down in this mono mix while not robbing the arpeggio of its inherent energy and vibe.
All of the stereo image was still there, just moved around in a rather unique way. Field and Focus are really nothing like panning, and we'll again refer to you the photograph analogy above to help you grasp what's different.
We could go on about other examples, but we feel these two sum up our impressions of how DrMs can be used to manipulate full mixes and individual tracks to achieve results that you just couldn't get with any other tool that we're aware of. This plug-in, especially at this price, definitely has a place in the toolboxes of the creative mixer, desperate mastering engineer, or anyone who finds themselves wanting to do some very unique manipulation of stereo image. The ability to invert the stereo image with the Field and Focus controls, as well as the ability to manipulate phase relationships and to delay signals, makes DrMs just about the most unique M/S processor out there, if not one of the most unique plug-ins we've seen in a long time. It's a great gift idea for the geekiest and tweakiest of engineers. Visit the website, and try the free demo.

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