KERN WIDE vs Mastering The Mix STEREOVAULT

why this guide exists

Mastering The Mix shipped STEREOVAULT in May 2026, and it is the most ambitious stereo plugin to land in a while: a six-tab stereo toolkit in one interface, plus an Analyze button that listens to your source and suggests a starting preset. at $80 it sits in the mid tier, above the free options and below Leapwing StageOne 2.

i make KERN WIDE, a $29 stereo widener that picks a narrower fight: one technique (allpass decorrelation across 40 ERB-spaced bands) done deeply, with a per-band correlation constraint so the width survives mono playback. this guide compares the two honestly. where STEREOVAULT is the better tool for your work, i will say so.

(this is the head-to-head. if you want the full landscape, the best stereo widening plugins roundup compares thirteen tools including both of these.)

what STEREOVAULT does

STEREOVAULT’s design philosophy is breadth. instead of picking one technique and exposing its parameters, it spreads stereo tools across six tabs and lets you audition them against your source:

• Spread holds three width modes: Pristine (M/S balance, the transparent baseline), Diffuse (allpass-based width), and Vintage (an Orban-style pseudo-stereo for turning mono into stereo).
• Creative holds five character modes: Stretch, Flux, Chorus, Haas, and Space, for movement, dramatic width, and depth.
• Panorama, Width, Rotate, and Clean round it out with panning and skew, blend and balance, stereo rotation, and per-side mid/side EQ.

two design choices stand out. the Analyze button listens to your source (you can also feed it a reference track) and suggests a preset (Focused, Balanced, Wide, or Super Wide), a genuine help if you would rather not learn the mode-by-mode landscape. and every adjustment is automatically level-matched, so when you A/B you are comparing width and tone, not volume, which most plugins in this category leave you to do by hand. a Scope meter monitors stereo correlation and flags phase cancellation as you work.

what STEREOVAULT does not do is pick a side on mono compatibility, because it spans the full range. its Pristine (M/S) and Diffuse (allpass) modes fold down cleanly; a Haas mode produces comb-filter notches in mono, by the nature of a short-delay technique. the safety depends on which mode you reach for, and the Scope meter is a global readout rather than a per-band guarantee.

what WIDE does differently

WIDE is not trying to be STEREOVAULT with fewer features. it is built around one architectural bet.

one technique, taken deep

WIDE uses a 40-stage allpass biquad cascade with center frequencies spaced on the ERB (equivalent rectangular bandwidth) scale.[^1] an allpass filter passes every frequency at unity gain but shifts the phase differently at each one, so the output is spectrally identical to the input but phase-decorrelated. assign the decorrelated copy to one channel and the original to the other, and you get width that folds down to mild spectral ripple (typically under 2 dB) instead of the deep comb notches a Haas delay produces.[^2]

ERB spacing means the decorrelation profile matches how your ears resolve frequency: finer in the sensitive 1 to 4 kHz midrange, coarser at the extremes. it is the same perceptual scale SMOOTH uses for resonance, applied here to phase.

the per-band correlation constraint

this is the part STEREOVAULT does not expose. WIDE monitors the interaural cross-correlation in all 40 ERB bands in real time and prevents any single band from dropping below a safe threshold. a global correlation meter (STEREOVAULT’s Scope, or any correlation readout) can sit at a comfortable +0.4 while a narrow band at 2 kHz has quietly gone to -0.3 and will cancel on a mono system. the per-band constraint catches that case automatically. you hear width that does not collapse, without watching a meter.

three modes, four knobs, a bass crossover

WIDE still offers STEREO (allpass), M/S (side boost for already-stereo material), and HAAS (short delay) modes, with four knobs: WIDTH, SPEED, FOCUS, and MIX. FOCUS sets a bass crossover that collapses everything below it to mono, so the low end stays centered and headroom-efficient.

no iLok, $29 forever

WIDE activates once via Lemon Squeezy, caches the license locally, and runs offline forever after. no iLok account, no activation calls during playback, no dongle. it is $29 once, with free updates.

the comparison table

sound: where the two diverge

i have not had STEREOVAULT on a real session long enough to publish a fair head-to-head listening write-up. what follows is an architectural read, not a verdict. i will update this section once i have run real material through both.

• on a mono source you want to widen (a lead vocal, a mono synth), STEREOVAULT’s Vintage (Orban) mode and WIDE’s STEREO (allpass) mode are the relevant comparison. both create width from nothing. the allpass approach tends to hold its tone more neutrally on fold-down; the Orban character is its own flavor. preference, not a winner.
• on a pad or atmosphere, STEREOVAULT’s Flux and Space, two of its Creative-tab modes, are purpose-built for movement and depth. WIDE’s allpass is static by comparison. if you want the stereo image to breathe, STEREOVAULT has dedicated tools for it and WIDE does not.
• on anything headed for a club system or a phone speaker, WIDE’s per-band constraint is the differentiator. you can push WIDTH and trust that no single band has quietly gone out of phase. with STEREOVAULT you choose a mono-safe algorithm and check the fold-down yourself.

the honest summary: STEREOVAULT wins on creative range and on doing the thinking for you. WIDE wins on depth in the one technique that matters most for mono-critical work, and on never letting a band collapse.

features compared, point by point

technique breadth

STEREOVAULT wins this outright. six tabs spanning M/S, allpass, and pseudo-stereo width, plus creative modes (Stretch, Flux, Chorus, Haas, Space), panorama, rotation, and mid/side cleanup, is more than any other plugin in this price range. WIDE offers three modes, but its center of gravity is the one allpass technique. if you want one plugin that can be many kinds of stereo tool, STEREOVAULT is the answer.

mono safety

WIDE wins on safety-by-default. its only widening technique is the mono-safe one, and the per-band ICC constraint removes the need to watch a meter. STEREOVAULT can be just as safe, but only if you stay on the safe modes and watch its Scope meter; its Haas mode is deliberately not mono-safe. the difference is whether safety is the default or a setting.

workflow: analyze vs knobs

STEREOVAULT’s Analyze button and four suggested presets lower the barrier for anyone who would rather not learn the technique landscape. WIDE gives you four knobs and expects you to use your ears. for a producer who wants a fast, guided starting point, STEREOVAULT is friendlier. for someone who already knows what allpass width sounds like, WIDE is fewer clicks to the result.

level-matched A/B

STEREOVAULT level-matches every adjustment automatically. this is genuinely useful and WIDE does not do it: when you change WIDTH in WIDE, perceived loudness can shift slightly and you have to account for it. point to STEREOVAULT.

latency

WIDE’s allpass cascade adds only a few milliseconds (roughly 2 to 5 ms), low enough that it never needed a separate low-latency mode and stays usable for tracking. STEREOVAULT’s latency varies by mode (its creative and depth modes cost more than plain M/S). for live monitoring on the allpass path, WIDE is comfortably low.

formats

STEREOVAULT ships VST3, AU, and AAX. WIDE is VST3 and AU only, with no AAX. if you work in Pro Tools natively, STEREOVAULT is the one of the two that fits.

licensing, ownership, and price

WIDE is $29 forever: one-time Lemon Squeezy activation, then offline, three device activations per key, no iLok. STEREOVAULT lists at $80 (launched May 2026 with an introductory discount). the price gap is roughly 2.5x to 3x at list. WIDE pays for itself on one project; STEREOVAULT pays for itself if the technique breadth and the analyze workflow are doing real work for you.

decision framework

get STEREOVAULT if

• you want one plugin that covers many stereo techniques (M/S, creative width, Haas, modulation, panorama, rotation) instead of buying several.
• you like an analyze-and-suggest starting point over setting controls by ear.
• level-matched A/B is part of how you work.
• you need AAX for Pro Tools.
• you want creative stereo character (the Flux and Space modes) as much as corrective widening.

get WIDE if

• you mostly need mono-safe widening and want safety to be the default, not a setting you have to choose correctly.
• you want the per-band correlation constraint so no frequency region collapses on a phone speaker.
• you want lifetime ownership at $29 with no iLok.
• you mix electronic, hip-hop, or anything that lands on club systems and small speakers, where mono fold-down is non-negotiable.
• you prefer four knobs you set directly over a preset-suggestion workflow.

get both if

• you want STEREOVAULT for creative range and WIDE as the safe default on anything mono-critical.
• you A/B the allpass character against STEREOVAULT’s Flux on pads and keep the cleaner result per source.

frequently asked questions

frequently asked questions

is KERN WIDE a real alternative to STEREOVAULT?

for mono-safe widening, yes. WIDE at $29 focuses entirely on allpass decorrelation across 40 ERB-scale bands and constrains the correlation in each band in real time, so the width holds up on a phone speaker. STEREOVAULT at $80 is a six-tab stereo toolkit: a Spread tab (Pristine for M/S, Diffuse for allpass width, Vintage for Orban-style pseudo-stereo), a Creative tab (Stretch, Flux, Chorus, Haas, Space), plus panorama, width, rotation, and mid/side cleanup tabs, with an analyze button that suggests a preset. if you want one mono-safe widener that does the allpass job deeply, WIDE covers it for a third of the price. if you want technique breadth in one plugin, STEREOVAULT is the broader tool.

how much does STEREOVAULT cost compared to WIDE?

STEREOVAULT lists at $80 / £59 (it launched in May 2026 with a free-bonus-plugin offer that has since ended). KERN WIDE is $29 forever with no upgrade fees, no iLok, and one-time activation. that is roughly a 2.5x to 3x price gap. verify STEREOVAULT current pricing on the Mastering The Mix site before relying on it.

which is more mono-compatible, WIDE or STEREOVAULT?

it depends which STEREOVAULT algorithm you use. STEREOVAULT spans the full range, from mono-safe (its Pristine M/S and Diffuse allpass modes) to deliberately not (a Haas mode combs on mono fold-down, by the nature of a short-delay technique). WIDE only does allpass decorrelation and adds a per-band correlation constraint that prevents any single ERB band from collapsing in mono. if mono safety is the priority and you do not want to think about which algorithm is safe, WIDE makes that the default rather than a choice.

does STEREOVAULT have an analyze feature WIDE does not?

yes. STEREOVAULT has an Analyze button that listens to your source and suggests a preset (Focused, Balanced, Wide, or Super Wide). WIDE has no analyze-and-suggest workflow: you set WIDTH, SPEED, FOCUS, and MIX by ear. if you prefer a smart starting point over learning the controls, that is a real STEREOVAULT advantage. if you prefer four knobs you set directly, WIDE is faster once you know it.

does WIDE require iLok or an internet connection?

no iLok. WIDE activates once over the internet via Lemon Squeezy on first launch, caches the license locally, and runs offline forever after, with no online checks during playback. if avoiding iLok and activation servers matters to your workflow, WIDE is built around that constraint.

should I get WIDE, STEREOVAULT, or both?

get WIDE if you want one deep, mono-safe widener at $29 and you mostly need allpass decorrelation with a bass crossover. get STEREOVAULT if you regularly switch between technique families (M/S for one source, a creative width mode for another, Haas for a third) and want one interface plus level-matched A/B. getting both is reasonable if you want STEREOVAULT for creative breadth and WIDE as the safe default on anything headed for a club system or a phone speaker.

references

a note from the developer

i respect what Mastering The Mix did with STEREOVAULT. putting a whole stereo toolkit behind one analyze button, and level-matching every move, is a real answer to a real problem: most people do not want to learn the difference between mid/side balance and an allpass spread, they just want their track wider without it falling apart. that is a good design goal and the level-matching alone is something i wish more plugins did.

WIDE answers a narrower question. i wanted stereo expansion that survives mono playback without me having to think about it, so i built one technique deeply: allpass decorrelation on the ERB scale, with a per-band correlation constraint running on all 40 bands inside a 3% CPU budget. that constraint is invisible when it works. you push WIDTH, the image opens up, and it still holds together when someone plays it on a phone. the cost of that focus is range: WIDE does not do the creative movement and depth modes, and if you want those, STEREOVAULT is the better buy.

i am a solo developer in Copenhagen. if you have used both and your ears tell you something different from what i wrote here, i want to know. reach out at jonas@kernaudio.io.