POST DATE : 30 June 2026
IMAGE BY : Mastering The Mix
WRITTEN BY : Joe Palmer
Stereo width is an integral part of music; it’s what gives songs a sense of depth and three-dimensional space. Proper stereo imaging can make a mix sound bigger, more immersive and more professional, giving each sound its own location in the space. Width is best understood as the difference between the left and right channels; if the sound is identical in the left and right, it’ll sound like it’s coming from the middle, and the greater the difference between the left and right channels, the wider it’ll sound. This is often achieved with panning, which increases the volume in one channel whilst decreasing it in the other.
There are other, more sophisticated ways of controlling the stereo image of a track, but these are often misunderstood or misused. Many producers will reach for a stereo widening plugin without understanding what it does, which can lead to phase issues, poor mono compatibility or poor translation to other listening devices.
Mastering The Mix aims to solve these problems with STEREOVAULT, an all-in-one tool designed to give you complete control over the stereo image of your sounds. Instead of focusing on one technique, STEREOVAULT combines multiple stereo processors to give you all the options you’ll need for precise stereo placement. It’s a complete imaging suite, with classic widening, creative panning, stereo modulation, multi-band control and much more.
It’s a very strong concept for a plugin: STEREOVAULT aims to be the last stereo processing plugin you’ll ever need, with all of the classic and creative tools necessary for any job. But does it deliver the results to back it up? Does it stand out when compared to the other imaging plugins on the market? This review will take a close look at all the processing types, workflow, quality-of-life features, pros and cons to help you decide if STEREOVAULT is the best option for managing your song’s stereo image.
Key Features
> Intelligent stereo analysis with visual feedback.
> Multiple options for stereo widening and positioning
> Capable of subtle and extreme stereo processing
> Tools for improving clarity, focus and mono compatibility
> Creative stereo effects for psychoacoustic sound design
> Suitable for mixing and mastering work
Using STEREOVAULT
STEREOVAULT is built around one main UI; a detailed stereo visualizer split into separate bands. This makes it easy to visualize the current image balance and any changes you make to it. The different processing modes are at the bottom, allowing you to quickly click through the different modules to make adjustments and try out different algorithms. The workflow works best with a goal in mind. If you need more width, you can try the different modes in the Spread and Width modules. If you need to reposition the sound, you can use Panorama or Rotate. If you need to clean up a messy stereo image, Clean is the module for you, and for more experimental use, Creative has everything you need for advanced imaging effects.
This flexibility makes STEREOVAULT useful for composition, mixing and mastering. The Creative effects can completely transform a sound, letting you explore the different possibilities for psychoacoustic and unrealistic stereo positions. For background sounds or experimental tracks, using this module is an easy way to create depth and movement without overly altering the character.
The other modules have strong applications for both corrective mixing and mastering. Width is the most useful for basic width control, giving you more advanced control than the basic “width” knob that’s built into most DAWs. I’d rather use STEREOVAULT here for more detailed multi-band control and the Balance or Blend modes, which make a noticeable difference to the stereo stability when used across a track. Spread goes beyond this, with options for extreme and unrealistic width, which adds an extra dimension to the stereo field, creating a clear separation between “wide” and “super-wide” sounds. Panorama and Rotate tackle panning differently; Panorama allows for extra precise placement, whilst Rotate adds a psychoacoustic positioning effect for even more depth and a sense of real “location” in the song. Clean is more useful for recovering recordings with unbalanced stereo images, which can be highly useful for multi-track or mixed sound source recordings.
I’m not a big fan of stereo manipulation in mastering, I believe that stereo issues are much better fixed in the mixing stage, and I advise caution when widening or narrowing entire songs, even with the multi-band capabilities of STEREOVAULT. That being said, sometimes it is unavoidable, and STEREOVAULT gives you great options for transparent, non-destructive imaging; I would use the diffuse mode in Spread for adding subtle width, the balance mode in Width for tightening the bass frequencies, or the Clean module if there were any issues with stereo build-up overwhelming the balance of the song. For both corrective mixing and mastering, I would recommend restraint when using STEREOVAULT; small changes can help to balance the stereo image, whilst more dramatic changes can negatively affect the tone, phase relationships and mono compatibility.
Workflow and Quality-Of-Life Features
Beyond the processing modes, STEREOVAULT has some great workflow and quality-of-life features. The Smart Analysis tool is a great option for beginners; it analyses your track and suggests a starting point preset. This goes against my advice about using it with intention, but if you’re new to stereo image mixing, it’s useful to know how your sounds can be enhanced, and then customise them further to better suit your track. The presets are fairly basic, and I’d recommend them mainly as starting points for exploration, but they’re still a great demonstration of the plugin’s capabilities. The Creative presets are especially strong for showcasing STEREOVAULT’s potential as a sound design plugin; Slow Drift and Wide Motion are excellent examples of the Flux modes modulation capabilities.
The visualizer is another standout feature. Especially useful for producers with budget headphones or speakers, the visualizer gives accurate feedback on a sound’s stereo image and reacts immediately to any changes you make, making it much easier to understand how the processing affects the signal. It’s also highly customizable, letting you switch between 2D and 3D modes, different FFT algorithms, time-based smoothing and even letting you freeze the visualizer to better analyse the image. This is most useful on complex tracks, like buses or the master channel; being able to analyse the stereo image from all angles makes a surprisingly big difference when figuring out how it should be shaped.
Since the plugin uses multi-band processing, the Transparent and Flexible band modes are another highly useful tool. Transparent mode gives you clean, predictable processing with linear-phase band splitting, whilst Flexible allows you to be more creative and focus on smaller areas of the frequency spectrum for precise targeting and interesting sound design effects.
Finally, STEREOVAULT includes several professional monitoring options to help with unbiased decision making. A/B mode allows you to quickly compare different settings, Auto Level Matching helps to avoid the louder-is-better bias, and Delta monitoring allows you to hear the difference between the dry and processed signals. I highly appreciate Delta mode in plugins, as it clearly shows exactly what’s being changed in the signal, and it’s especially useful in stereo processing for identifying artifacts, excessive widening, phase cancellation or other unwanted side-effects.
Overall, STEREOVAULT is very well thought out, with no major flaws or missing features. There is some overlap between modules (do I want to widen the sound with Spread, Width or a Creative mode? Do I want to pan using Panorama or Rotate? Do I need to use Clean, or would a mid-side EQ better solve the issue?), and the depth of the controls can be overwhelming at first, but once you understand what every control does it becomes an invaluable tool for stereo processing. There are some highly-experimental, sound design based stereo plugins that offer features beyond what the Creative module can do, but for basically any other imaging task STEREOVAULT has become my new go-to tool.
The Processing Modes
Spread
> Features three widening algorithms: Pristine, Diffuse, and Vintage
> Includes controls for width, intensity, and stereo enhancement
Spread is STEREOVAULT’s main option for creating width in sounds. Pristine mode works like a traditional stereo imager, increasing the level of side-channel information (the differences between the left and right channels) relative to the mid (or mono) channel. Diffuse uses phase diffusion to create width and separation: tiny frequency-dependent phase shifts are introduced between the left and right channels, creating width with new stereo differences rather than amplifying existing ones. Vintage is based on a hardware trick that can turn mono sounds into stereo. Similar to Diffuse, it works on small frequency-dependent sections of the channel, but instead of near-transparent phase shifts it uses more aggressive processing, resulting in a more colourful and altered sound.
Panorama
> Controls stereo positioning and image balance
> Includes Pan and Skew controls
> Can rebalance uneven stereo recordings
> More flexible than traditional panning
The Panorama module focuses on positioning the sounds in the stereo field. Pan works like a traditional pan control by shifting a sound toward the left or right. Skew allows you to rebalance a sound without moving the image as a whole, redistributing the stereo information between the channels to create a more balanced sound that stays close to its original position and retains a sense of width. This allows you to correct recordings that feel uneven without completely repositioning them, which is a pretty advanced concept.
Width
> Controls the balance between Mid and Side information, allowing independent control of each
> Balance and Blend controls
> Can be used to tighten or expand the overall stereo image
> Useful for improving mono compatibility
While Spread allows you to create width, the Width module is for controlling it. It’s a pretty simple module, allowing you to control the Mid and Side balance of each band. It’s most suited to bus or master processing where tightening the stereo image is as important as expanding it. The Balance mode gives you easy control of the loudness balance between the Mid and Side channels, whilst Blend sums the Side channels together into the Mid channel, keeping more of the unique character but risking potential phase issues.
Rotate
> Rotates the stereo image, rather than just widening or panning sounds
> Can reposition sounds without traditional panning
> Useful for advanced positioning, stereo movement and creative processing
> Can range from very subtle to extreme
Rotate is a more advanced panning tool than Panorama. It rotates the sounds stereo information in degrees, rather than shifting them to one side. It’s a hard effect to explain in words, but you can hear the difference as you shift the controls, almost like moving your head to hear the sounds in different positions, rather than moving the sounds themselves. It’s pretty niche in corrective mixing, but there are some fun sound design and psychoacoustic effects to be made here, especially when you modulate the positions to create a moving, shifting effect.
Clean
> Allows independent gain control for Mid and Side information
> Useful for tightening low-frequency sounds, reducing mud and fixing stereo build-up
> Designed to improve focus and clarity
Clean is actually more simple than it seems. It works like a multi-band Mid/ Side gain control for increasing or attenuating the gain of the channels individually. This is useful for basic adjustments when mixing, but the Spread and Width modules will usually be more useful for precise changes. I’d use it more like a safety net for heavier processing with the other modules; adding Width, Rotate or Panorama can create an unbalanced signal, and Clean is a great way of dialing it back whilst keeping the perceptual effects intact.
Creative
> Stereo-focused, more experimental sound design effects
> Includes Stretch, Flux, Chorus, Haas and Space processing
> Can create movement, depth and exaggerated, unnatural width
The Creative module is where STEREOVAULT gets fun. Stretch mode exaggerates the stereo image for unrealistic, extreme width, Flux introduces subtle motion to add life and movement to the sound, Chorus adds the classic chorus effect, Haas uses tiny time-delays on each channel to add a perceived width, and Space adds a reverb with a very short decay to give a sense of “room” or “space” to the sound. None of these are revolutionary effects, but when spread across the multiple bands and combined with the other modules, it can create some interesting and experimental sounds.
Pros / Cons
Pros
> Combines almost every stereo processing tool into a single plugin
> Excellent visual feedback and monitoring tools
> Smart analysis can provide useful starting points
> Versatile algorithms and processing modes for any workflow you need
> Automatic level matching for avoiding loudness bias
> Suitable for both mixing and mastering
> Great balance between corrective and creative processing
Cons
> Can be overwhelming compared to simpler stereo plugins
> Some overlap between modules
> Can be overused, leading to tone changes, phase issues and poor mono compatibility
Final Verdict
STEREOVAULT has become my go-to stereo processing plugin. The variety of effects, multi-band approach, detailed feedback and monitoring tools make it incredibly versatile and adaptable. The sounds you can create by stacking modules or automating controls are genuinely impressive, and for my style of music (ambient, electroacoustic and heavily experimental) this is a major upgrade. All of these effects can be created by combining other stereo plugins, but the versatile and simple workflow make STEREOVAULT extremely easy and satisfying to use.
This is a plugin for mixing engineers who truly care about stereo image, musicians who see the value of depth and space in their songs, and sound designers who want to enhance their results with a sense of movement and location. I would recommend the free trial to anyone who isn’t sold on the idea; even if you only use basic stereo widening at the moment, STEREOVAULT can show you the power of advanced, extreme and experimental stereo processing.
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