By contrast, a test signal has a fixed frequency content and a precisely defined duration.
This takes into account the frequency content, rise time, etc.
A sharp noise like a hand clap has more high frequency content than low.
What is then delivered to the computer is already processed information about the frequency content, pitch, energy and so on.
Then the digital filter removes the unwanted high frequency content.
"When people speak this long, you get enough of an idea of the frequency content of the various sounds in their voices."
It is not used for testing loudspeakers as its spectrum contains too great an amount of high frequency content.
In both cases energy is supplied to the system with a known frequency content.
It is so far unclear if a remastered version with full frequency content will be released.
Equalizers - used to manipulate the frequency content of signals.