Mathematica Tutorial: Visualization And Graphics - Wolfram Research

32 Visualization and Graphics
Play is set up so that the time variable that appears in it is always measured in absolute seconds.
When a sound is actually played, its amplitude is sampled a certain number of times
every second. You can specify the sample rate by setting the option SampleRate.
PlayA f ,9t,0,t max =,SampleRate->rE
play a sound, sampling it r times a second
Specifying the sample rate for a sound.
In general, the higher the sample rate, the better high-frequency components in the sound will
be rendered. A sample rate of r typically allows frequencies up to rê2 hertz. The human auditory
system can typically perceive sounds in the frequency range 20 to 22000 hertz (depending
somewhat on age and sex). The fundamental frequencies for the 88 notes on a piano range
from 27.5 to 4096 hertz.
The standard sample rate used for compact disc players is 44100. The effective sample rate in
a typical telephone system is around 8000. On most computer systems, the default sample rate
used by Mathematica is around 8000.
You can use Play@8 f 1 , f 2 , …D to produce stereo sound. In general, Mathematica supports any
number of sound channels.
ListPlayA8a 1 ,a 2 ,…rE
play a sound with a sequence of amplitude levels
Playing sampled sounds.
The function ListPlay allows you simply to give a list of values which are taken to be sound
amplitudes sampled at a certain rate.
When sounds are actually rendered by Mathematica, only a certain range of amplitudes is
allowed. The option PlayRange in Play and ListPlay specifies how the amplitudes you give
should be scaled to fit in the allowed range. The settings for this option are analogous to those
for the PlotRange graphics option discussed in "Options for Graphics".