Best FREE Linear-Phase EQ VST Plugins

This article covers the best free linear-phase EQ VST plugins for Windows and macOS.

Linear-phase EQs are essential for achieving transparent equalization, especially in mastering.

Unlike traditional EQs, a linear-phase equalizer preserves the phase of your audio, making it ideal for mastering and handling complex multi-mic recordings.

While free linear-phase EQ plugins are hard to find, this article will guide you to the best options.

Best FREE Linear-Phase EQ VST Plugins

These are the best free linear-phase equalizers in 2024:

• lkjb QRange
• iZotope Ozone 11 EQ
• Photosounder SplineEQ
• ZL Audio ZL Equalizer
• Moss Equalizer
• Voxengo Marvel GEQ

Keep reading to learn more about each plugin on the list.

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lkjb QRange

QRange is a free 12-band IIR linear-phase equalizer in VST and VST3 formats for PC and Mac. It is widely regarded as the best free linear-phase EQ plugin.

And this isn’t the only freeware EQ from lkjb. The developer also offers Luftikus, an excellent parametric EQ featured in our list of free EQ plugins.

However, unlike Luftikus, QRange is a transparent, linear-phase EQ. This makes it ideal for mastering and handling multi-mic recordings of the same audio source.

Despite the complex feature set, I love how lkjb’s interface remained intuitive. The upper section displays the EQ curve and a real-time spectrum analyzer, resembling a typical parametric EQ control layout.

So, even if you’re completely new to using a linear-phase equalizer, you won’t find QRange hard to figure out.

You can control the 12 frequency bands, which can be set as peak, shelf, or cut filters, and apply per-band routing for stereo, left, right, mid, or side adjustments.

QRange also allows you to view either pre or post-EQ analysis in the spectrum display, which is convenient if you want to fine-tune the frequency response. The bypass switch enables quick A/B comparison between the processed and unprocessed signals.

Linear-phase equalizers like QRange differ from standard (minimum-phase) EQs because they don’t cause phase shifting in the signal. However, they may introduce pre-ringing, which can result in an unwanted volume boost before transients.

While minimum-phase EQs often sound more musical, linear-phase EQs are particularly useful for preventing phase issues when processing multiple recordings of the same source, such as drums recorded with multiple microphones.

QRange is fully compatible with all VST and VST3 hosts on PC and Mac platforms. It is well-suited for audio professionals looking for precise control over their EQ settings without coloring the sound.

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iZotope Ozone 11 EQ

Ozone 11 EQ by iZotope is a versatile equalizer plugin from the Ozone suite of mastering tools. It is free as part of Native Instruments’ Komplete Start bundle.

The plugin features two global filter modes: Analog, which uses minimum-phase IIR filters, and Digital, which employs linear-phase FIR filters. In Digital mode, the plugin functions as a linear-phase EQ, preserving the original signal’s phase, although it demands more CPU resources.

I love how easy it is to switch between the Analog and Digital modes. If you’re looking for a single go-to equalizer plugin to substitute all others, Ozone 11 EQ is a great candidate because of this versatility.

When set to Digital mode, you can access the advanced controls, including the phase adjustment for each EQ band. In this mode, the phase can be adjusted between 0% (linear phase) and 100% (minimum phase), offering super-precise control over the phase response.

I also like the included Transient/Sustain mode, which allows independent processing of transient and sustain portions of a signal. This is ideal for nuanced mixing, where you want to slightly improve the tone of a drum without affecting the transients.

The Delta feature lets you hear the difference between processed and unprocessed signals. Gain Match is also handy as it ensures the signal remains at a consistent volume post-processing.

Ozone 11 EQ is available in AAX, AU, and VST3 formats for 64-bit Windows and macOS systems.

Thanks to BPB readers Thomas M and Dee for suggesting Ozone 11 EQ.

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SplineEQ

SplineEQ is a unique linear phase equalizer plugin designed for simplicity and flexibility. It uses Bézier splines for filter design, letting you create any imaginable curve for sound shaping.

Unlike traditional EQs, SplineEQ does not have specific filter types; instead, users manipulate points on a spline curve to define the filter’s shape. This lets you create up to four bands in the free version (and up to 60 in the paid version)

The interface is unusual but remains intuitive. It features smooth graphics and a spectrum analyzer that shows both pre- and post-EQ frequencies in real-time.

One feature I appreciate is the infinite dB to +60 dB gain range. It lets me completely silence or dramatically enhance frequencies. I find this particularly useful when working on a drum mix or a full stereo mix of a song.

SplineEQ excels at precision, and I’ve found it invaluable when fixing poor recordings. I like using it to add body to a lifeless kick drum or remove boxy resonances from vocals.

It’s impressive how natural and transparent the sound remains even after significant EQ adjustments. The built-in limiter also ensures the sound doesn’t clip or distort, even with extreme frequency boosts.

For sound design, SplineEQ is incredible. I’ve used it to extract individual instruments from a full mix and apply sweeping filter effects using the transpose function, which lets me smoothly shift the entire EQ curve.

Automation works seamlessly, and I’ve used it to create everything from subtle enhancements to mind-blowing cinematic sounds. The precision and control over sound are unparalleled, making it my go-to EQ for mastering projects where transparency is critical.

Another big plus is the low CPU usage, especially considering it’s a linear phase EQ. I’ve had projects with 20+ instances of SplineEQ and almost no negative effects on the performance.

One thing I’d like to see improved is the ability to group and move multiple EQ nodes together, which would be handy given the high number of control points.

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ZL Equalizer

ZL Equalizer is a free 16-band EQ plugin available for Linux, macOS, and Windows, offered in AU and VST3 formats.

It features 8 filter types, 5 processing modes (including linear-phase), and 7 variable slopes, providing precise control over EQ shaping.

I’m including ZL Equalizer here because of its linear-phase mode, which preserves the original signal’s phase but introduces up to 512 ms latency when using left/right or mid/side processing.

In linear-phase mode, the plugin delivers an analog-like magnitude response with zero phase distortion, though it disables dynamic effects and auto-gain compensation.

ZL Equalizer also provides high-quality audio processing with 64-bit floating-point precision, an interactive spectrum graph, and an optional dark mode—perfect for late-night mixing sessions.

It’s also worth noting that the plugin is open-source and available for download on GitHub.

Thanks to BPB readers SN, Robin, and Dee for recommending ZL Equalizer.

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Moss Equalizer

Moss Equalizer is a FFT equalizer plugin for Windows, available in VST2 and VST3 formats.

An FFT (Fast Fourier Transform) equalizer like Moss EQ is typically a linear-phase equalizer. FFT-based processing analyzes a signal’s frequency content, makes adjustments in the frequency domain, and then converts it back to the time domain.

Since this process does not alter the phase relationships between frequencies, the result is linear-phase filtering.

Moss Equalizer allows for steep frequency adjustments, ranging from -150dB to +60dB, covering the full frequency range of 10Hz to 20kHz. The plugin includes customizable FFT Size and Range controls, so you can customize how it shapes the signal.

My favorite feature is the comb filter modeling mode, which can create vocoder-like effects. You can also load custom frequency response files (.MEB format) for more advanced filtering.

Thanks to BPB reader Dee for recommending Moss Equalizer.

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Voxengo Marvel GEQ

Marvel GEQ is a free 16-band linear-phase graphic equalizer from Voxengo. It is available as an AudioUnit, AAX, and VST plugin, supporting up to 8 input/output channels.

Unlike the previous two entries, Marvel GEQ is a graphic equalizer, so it’s not suitable for surgical EQ corrections. Instead, it works great as a gentler musical EQ that you’d use for improving the overall tonal balance of a mix.

The plugin supports mid/side processing, stereo, and multi-channel operation with flexible internal routing. It offers a +/- 12 dB gain range per band, freehand drawing mode, and 64-bit floating point processing for high-quality sound.

I love using the freehand drawing mode to quickly adjust the tone of a mix. It’s like drawing a quick sketch on a piece of paper and using it as a starting point for a larger painting.

I use Marvel GEQ in a similar way. First, I draw a broad tone curve and then adjust the individual sliders to finalize the tone on the master channel.

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What is Linear-Phase EQ?

The concept of a linear-phase EQ may sound complicated, but in reality, it’s quite simple.

A linear-phase equalizer adjusts the intensity of frequencies without altering their phase. In other words, it preserves the timing and phase relationships within a signal.

It works by applying the same delay across all frequencies, which prevents phase shifts that typically occur in regular EQs. This is useful for tasks like mastering or working with multi-mic recordings, where maintaining phase coherence is important.

If you’ve ever mixed a multitrack recording of an acoustic drumkit, you’ll know how using a regular EQ can result in phasing issues – smudging or even complete removal of certain frequencies. Linear-phase EQ solves this issue because it doesn’t affect the phase of the processed signal.

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Linear-Phase EQ: Pros, Cons, and When to Use It

The main advantage of a linear-phase EQ is that it doesn’t introduce phase shifting, preserving the original phase relationships in the sound. This transparency allows for clean, accurate equalization without coloring the sound.

However, linear-phase equalizers aren’t perfect.

A key disadvantage is that linear-phase EQs can introduce pre-ringing, an artifact that can sound unnatural, especially on transients. They typically have higher latency and demand more CPU resources than regular (minimum-phase) EQs.

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For more freeware plugins and instruments, return to our Free VST Plugins page.