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0 pointsduped1y ago0 comments

The SVF has the same computational complexity as a TDF2 biquad (as it is after all, a TDF2 biquad). There are more efficient structures than either (eg: state space canonical forms which play nice with common matrix/vector arithmetic). The direct forms are pretty terrible for all but trivial SIMD optimization like interleaving. Depending on a few factors just packing the SIMD lanes for optimized biquads is more expensive than not using SIMD at all on deinterleaved channels.

Direct form 2nd order filters are a dead end in terms of performance and quality for pro audio. I just wanted to point that out, since this space is very well studied and direct forms have pretty notable disadvantages (stability under modulation, overhead of coefficient computation, poor SIMD optimizations, etc).

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ashafq1y ago

If I recall correctly, SVFs typically compute lowpass, highpass, and bandpass outputs simultaneously, which are then combined to create peaking or shelving filters. In contrast, a traditional biquad filter requires only five multiply-accumulate instructions. Computationally, SVFs are generally 3 to 5 times more expensive than biquad filters.

When designing this plugin, my primary focus was optimizing steady-state operation. While there are many plugins tailored for handling modulation, this plugin is designed to reject high-frequency modulation, prioritizing efficiency for gradual state changes. This tradeoff allows it to excel in its intended use case without the added complexity or overhead of robust modulation handling.

Feel free to add a feature request in the Github project page. Thanks again for your feedback.

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