The amplitude of a sound wave is the measure of the height of the wave. or where, represents wave, represents amplitude in the wave, are the wave function, represents angular frequency, represents time period and represents wave function
The sound wave is a mechanical wave that is created by a vibrating object.
The sound wave is perceived to be louder when amplitude increases.
The relation between intensity (loudness) and amplitude:
If the amplitude increases, the speed will be decreases.
The amplitude does not affect wavelength because amplitude is the energy of the wave measured from the rest position to the top of the crest.
Also if the frequency is increased, the amplitude decreases because the energy is proportional to the square of frequency and the square of the amplitude.