In frogs and toads,tympanum is a large external oval shape membrane made up of nonglandular skin.it is located just behind the eye. It does not actually process sound waves; it simply transmits them to the amphibian's inner ear, which is protected from water and other foreign objects.
A frog’s ear drum is called a Tympanum and works in very much the same way that our human ear drums work. A frog’s ear drum, just like a humans ear drum, is a membrane that is stretched across a ring of cartilage like a snare drum that vibrates. There is rod that is connected to the ear drum, which vibrates by sounds that come at the frog. That sound is just pressure waves. The rod sloshes around in the inner ear fluid, which causes microscopic hairs to move, which send signals to the frog’s brain for interception. A frog’s ear lungs also vibrate when sound waves come toward it, although they are less sensitive than the frogs ear drum.