TfxEcho is an echo effect AudioUnit Extension plugin that utilizes delay lines inspired by the bucket brigade device (BBD) known for its warm and dark sound. The delay lines feature fixed-length buffers and an artificial clock for sampling input signals at variable rates, allowing for pitch change effects similar to analog delay units. Unlike traditional BBD units, TfxEcho's delay line can capture signals up to 22KHz, offering an extended frequency range.

This AudioUnit Extension plugin offers adjustable delay time ranging from 20 ms to 1200 ms, feedback control from 0% to 100%, and customizable low-pass and high-pass filters. Users can also adjust modulation rate from 0.01 Hz to 10 Hz, modulation width from 0 ms to +/- 10 ms, and sync delay time to the tempo of the host application.