Fractionally-addressed delay lines

TL;DR

This paper introduces a novel fractional pointer-based delay line implementation that simplifies variable-length digital delay lines, offering efficiency and suitability for audio effects and wave simulation.

Contribution

It presents a new fractional-addressed delay line method that improves upon traditional circular buffer approaches in digital audio processing.

Findings

Nearly as efficient as interpolated circular buffers on modern architectures

Performs well for delay-length modulations in audio effects

Suitable for simulating tension or density modulations in wave media

Abstract

While traditional implementations of variable-length digital delay lines are based on a circular buffer accessed by two pointers, we propose an implementation where a single fractional pointer is used both for read and write operations. On modern general-purpose architectures, the proposed method is nearly as efficient as the popularinterpolated circular buffer, and it behaves well for delay-length modulations commonly found in digital audio effects. The physical interpretation of the new implementation shows that it is suitable for simulating tension or density modulations in wave-propagating media.