Compression Ratio (audio)

A compression ratio controls the ratio of input to output levels above a specific threshold. This ratio determines how much a signal has to rise above the threshold for every 1 dB of increase in the output. For example, with a ratio of 3:1, the input level must increase by three decibels to produce a one-decibel output-level increase:

Threshold

-10 dB

Compression Ratio

3:1

 

 

Input

-7 dB

 

 

Output

-9 dB

 

 

Because the input is 3 dB louder than the threshold and the compression ratio is 3:1, the resulting signal is 1 dB louder than the threshold.

Compression Ratio (file size)

The ratio of the size of the original uncompressed file to the compressed contents. For example, a 3:1 compression ratio means that the compressed file is one-third the size of the original.

Computer ID

Each computer has a unique number, similar to a license plate. An activation number is created based on that number. Since the activation number is based on the Computer ID, it is important that you have Sound Forge software installed on the computer where you will be using it. The Computer ID is automatically detected and provided to you when you install the software.

Note: The Computer ID is used for registration purposes only. It doesn't give Sony access to any personal information and can't be used for any purpose other than for generating a unique activation number for you to use the software.

See also Activation Number on page 343.

Crossfade

Mixing two pieces of audio by fading one out as the other fades in:

Crossfade Loop

Sometimes a sample loop cannot be easily created from the given source material. In these instances, a crossfade can be applied to the beginning and end of the loop to aid in the smooth transition between the two. The Crossfade Loop function provides a method of creating sampling loops in material that is otherwise difficult to loop.

Cutoff frequency

The cutoff frequency of a filter is the frequency at which the filter changes its response. For example, in a low-pass filter, frequencies greater than the cutoff frequency are attenuated, while frequencies less than the cutoff frequency are not affected.

Data Window

Each opened sound file has its own data window. At the top of each data window is a title bar displaying either the title of the sample or the name of the file. Also in each data window are the waveform display, time and level rulers, playbar and other tools that give you information and allow you to navigate throughout the entire sound file.

346 APPENDIX E