Acoustics, vibration and sonar

Room modes, decay curves, loudspeaker response, machinery vibration and passive sonar. Acoustics is a decibel discipline: nearly every quantity here is already logarithmic, so the axis choice is about frequency spacing and dynamic-range floors rather than about whether to take a log at all.

Room acoustic modal pressure

Room acoustic modal pressure

Sonar range-bearing display

Sonar range-bearing display

Third-octave noise spectrum against a limit curve

Third-octave noise spectrum against a limit curve

Reverberation decay and the T60 extrapolation

Reverberation decay and the T60 extrapolation

Machine vibration spectrum with bearing sidebands

Machine vibration spectrum with bearing sidebands

A pressure pulse bouncing down a rigid duct, animated

A pressure pulse bouncing down a rigid duct, animated

A standing wave, actually standing: room modes in time

A standing wave, actually standing: room modes in time