Coupled Piano Strings

Perhaps it should be emphasized here that for good piano synthesis, multiple filtered delay loops should be employed for each note rather than the single-loop case shown here, as discussed in §4.12. The multiple delay loops may correspond to multiple strings hit by the same hammer, both polarization planes on a single string, and/or longitudinal waves. Thus, in a piano synthesizer, there should be at least two filtered delay loops, slightly detuned (different loop delays), both excited by $g(t)$ in some manner^6.4 (e.g., they can each receive an identical copy), and the delay loop outputs should be summed or else realistically coupled as described in §G.11 [444]. A digital waveguide piano synthesis implementation including both transverse and longitudinal waves is described in [29].