Elliptic BLEP
High-Quality Zero-Latency Anti-Aliasing
BLIT/BLEP/BLAMPs are a useful tool to reduce aliasing in basic waveforms, nonlinearities, and hard-sync synthesis. There are many variations, but most of them require some lookahead and bookkeeping to work properly.
We start by looking at where aliasing comes from in these situations, how BLEP and friends can help, and the compromises of some common variations.
We'll then introduce a new IIR-based approach based on Holters-Parker resampling. This approach has a simple zero-latency implementation, and has extremely good aliasing-reduction based on elliptic filters.
An implementation will also be released as a zero-dependency open-source C++ library (single-file header). This can also be used as an arbitrary-rate resampler for modulated delay lines and sample playback.
Geraint Luff
Director
Signalsmith Audio
I run Signalsmith Audio, a small audio/DSP consultancy based in the UK.