In this paper we introduce a novel approach utilizing real-time concatenative synthesis to produce a Feature-Based Delay Line (FBDL). Expanding upon the concept of a traditional delay, its most basic function is familiar – a dry signal is copied to an audio buffer whose read position is time shifted producing a delayed or "wet" signal that is then remixed with the dry. In our implementation, however, the traditionally unaltered wet signal is modified such that the audio delay buffer is segmented and concatenated according to specific audio features. Specifically, the input audio is analyzed and segmented as it is written to the delay buffer, where delayed segments are matched to a target feature set, such that the most similar segments are selected to constitute the wet signal of the delay. Targeting methods, either manual or automated, can be used to explore the feature space of the delay line buffer based on dry signal feature information and relevant targeting parameters, such as delay time. This paper will outline our process, detailing important requirements such as targeting and considerations for feature extraction and concatenation synthesis, as well as discussing use cases, performance evaluation, and commentary on the potential of advances to digital delay lines.

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