SplineEQ FREE
Key Features
- Linear phase processing eliminates phase distortion and aliasing artifacts — shapes frequency intensity without coloring the sound
- Bezier spline curve editor lets you draw any filter shape by dragging control points and handles, no traditional filter types needed
- Real-time color-coded frequency analyzer shows pre and post-EQ spectrum for visual feedback while sculpting
- Curve modification tools: transpose up/down 10 octaves, adjust overall gain, scale to flatten or exaggerate the curve shape
- Adjustable filter resolution (down to ~22 Hz) and latency for balancing CPU usage against precision
- 64-bit floating point processing at any sample rate up to 384 kHz with built-in limiter for safety
Description
SplineEQ FREE is a linear phase equalizer that takes a completely different approach to EQ design. Instead of choosing filter types and adjusting parameters, you draw Bezier spline curves directly on the frequency spectrum. The plugin shapes only the intensity of frequencies without affecting phase, which avoids the smearing and coloring that minimum phase EQs introduce.
The spline-based interface lets you drag control points and tangent handles to sculpt any filter shape imaginable. A color-coded frequency analyzer shows the spectrum before and after processing in real time, making it easy to see exactly what the EQ is doing.
The FREE version supports up to 4 bands with the same audio engine as the paid version. Curve modification tools let you transpose the entire curve up or down by up to 10 octaves, adjust overall gain, or scale the curve shape to flatten, exaggerate, or invert it.
Filter resolution and processing latency are adjustable, letting you trade CPU usage for precision. All processing runs in 64-bit floating point at any sample rate up to 384 kHz.
SplineEQ has earned a 4.5/5 rating on KVR Audio, with one reviewer noting it's "on par with the very best there is on offer in the digital domain." MusicRadar called it "innovative and powerful."
Video Preview
Frequently Asked Questions
What is the difference between SplineEQ FREE and the paid version?
The FREE version supports up to 4 bands while the paid version ($29) supports up to 60. The paid version also adds preset saving and loading. All other features including the audio engine, curve tools, and analyzer are identical.
What are the disadvantages of linear phase EQ?
Linear phase EQs introduce latency because they process audio using FFT rather than real-time filters. This makes them less suitable for live monitoring or tracking. They can also soften low-frequency transients. SplineEQ lets you adjust the latency/resolution tradeoff to minimize this.
What is the best free linear phase EQ plugin?
SplineEQ FREE is consistently ranked among the top free linear phase EQs. Bedroom Producers Blog lists it alongside ZL Equalizer, iZotope Ozone 11 EQ, and Voxengo Marvel GEQ as the best options. SplineEQ's unique spline-based interface sets it apart from traditional parametric approaches.
Does SplineEQ work with FL Studio?
Yes. SplineEQ is available as a VST 2.4 plugin in both 32-bit and 64-bit versions, which FL Studio supports. It also works as an AU plugin for Logic Pro and other macOS DAWs.
