# Order Analysis

SonoDyno estimates engine speed, cylinder count and an engine-normalized load intensity from a microphone signal alone, with no tachometer, no bus access and no prior knowledge of the engine configuration. It feeds order energy at three time-frequency resolutions into a 124,302-parameter convolutional scorer that decides cylinder count and speed jointly, and a decoder constrains the speed trajectory. On two real engines it has never heard, 93 to 97 percent of frames land within 2 percent of the true speed, the cylinder count is identified with 80 percent accuracy, and fewer than 2 percent of frames suffer octave confusion.

SonoDyno estimates engine speed, cylinder count and an engine-normalized load intensity from a microphone signal alone, with no tachometer, no bus access and no prior knowledge of the engine configuration. It feeds order energy at three time-frequency resolutions into a 124,302-parameter convolutional scorer that decides cylinder count and speed jointly, and a decoder constrains the speed trajectory. On two real engines it has never heard, 93 to 97 percent of frames land within 2 percent of the true speed, the cylinder count is identified with 80 percent accuracy, and fewer than 2 percent of frames suffer octave confusion.