Human Eardrum (tympanic membrane), fresh but recently detached from its owner!
Measured as part of a research programme looking at synthetic tympanic membranes.
Shows the first resonance of the eardrum around 600Hz, where the right-hand half of the membrane is excited.
The malleus bone is attached in the '12 o'clock' position (The spikes far left are computational errors)

The effect of using orthogonal woven fibres in loudspeaker cones.
Mechanical impedance is different 'across' the weave compared to 'along' the weave,
giving rise to nonaxisymmetric bending wave behaviour.

12" guitar loudspeaker, showing the severe mechanical breakup which characterizes the sound of the driver.
Whereas the audiophile drive unit should impart no character to the sound,
the guitar driver is an integral part of the guitarist's 'instrument' and 'character' is all-important.

Horn, unrestrained at the mouth.
Showing classic 'bell-mode' behaviour which would be both audible and objectionable.
Fortunately much of this problem is alleviated when the device is mounted on a wooden baffle.