Most of us have heard of digital compression, but what does it really mean? And why is <strong>Sound Therapy</strong> so much better?
Digital Compression
Digital compression is mainly performed in the frequency domain. In compressed sound a few samples of the sound are taken but a large percentage of data, up to 90%, can be discarded. For the average listener the sound can still be recognized without this complex data. The result is a smooth wave form, from which many frequencies, especially the higher frequencies, are missing. This is the core of digital compression.
A single wave form smoothed out by compression is illustrated below. This is an illustration of typical MP3 sound.
In addition to frequency compression, sound is also compressed in time, so that fewer samples are played back each second. Here is an illustration of sound waves over a period of time.
After both the frequency and time domain compression processes, the spectrum datum are simplified as illustrated below. (Note: The illustration is overly simplified for easier understanding.) Thus, a huge amount of information is removed and permanently lost. (This is the reason why this type of compression is called “Lossy” Compression.) Moreover, MP3 often uses a lower sampling rate than a CD, which creates a total loss of information above a particular frequency (that being 1/2 of the sampling frequency). Note the sudden information loss over the specific frequency in the illustration.
