Nothing here is a plugin. The echo is a stereo tape loop with tone, saturation and wow written by hand; the space is a sixteen-line feedback-delay network with a Hadamard mix, per-line damping, slow detuned modulation on every line, and an octave shimmer in the loop. dry to speakers starts at zero on purpose: your flute is already in the room. The speakers only add the space. hold freezes the tank so you can play over your own chord. record writes a stereo WAV of exactly what the speakers get.