  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.
