Hey everyone! I’ve been getting some questions about why the phase looks so unusual when measuring the Shape2 Advanced plugin in Plugin Doctor. To help explain what’s going on, I’m sharing a tool that I use in the video. It’s a special filter plugin I built for myself over a year ago—a unique linear-phase filter called SPLITT (it’s actually the same filter used in Shape2 Advanced).
And here’s the best part: I’m giving it away as a freebie for you all! 🎉 Even though it’s quite specialized, I hope some of you will find it useful. It’s not your everyday filter, but if you’re into sound design and need some creative control over your frequency bands, this might come in handy.
What SPLITT Does
SPLITT is a linear-phase filter designed for splitting a signal into two bands—upper and lower—so you can process each separately. It’s also great for combining two different masters in a weird and fun way: use the low-band from one and the upper band from another, for example. As you probably understand by now, this is not meant for typical filtering tasks, but it offers a lot of flexibility for unique use cases!
Quick Start Guide
Here’s a rundown of the controls to get you started:
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Crossover: Set the frequency where the split will happen. Lower frequencies can be tricky to set with the knob, but you can type the exact value by clicking on the number below the knob.
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Taps: This adjusts the steepness of the filter. Higher values make the filter steeper, but they can also be taxing on your CPU. For most tasks, staying between 200-900 should work well, though you might need higher values (up to around 8000) if you’re working with very low frequencies (0–60 Hz). Pro tip: The maximum value (20000) is extremely CPU-intensive—use with caution!
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Matrix Controls: These options let you route the low and high bands individually:
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In LP (Low-Passed): Choose whether the low-band audio comes from the main stereo input (1-2) or the sidechain (3-4 input).
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In HP (High-Passed): Choose whether the high-band audio comes from the main stereo input (1-2) or the sidechain (3-4 input).
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LP Out: Set whether the low-band output goes to the main stereo output (1-2) or the 3-4 output channels.
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HP Out: Set whether the high-band output goes to the main stereo output (1-2) or the 3-4 output channels.
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I decided to only create a VST3 for now. I’m still figuring out signing and notarizing for Mac and won’t build any AU until I got that working.