Sound wave editors allow sounds to be modified in many different ways such as noise reduction, filtering, loudness adjustment etc. A good example of a sound editor program is Goldwave - this program is available as shareware from www.goldwave.com. Software distributed under the shareware concept can be tried free of charge - all software should be distributed this way! The trial version of Goldware allow 150 operations to be carried out before the program freezes. Restarting the program allows another 150 operations to be carried out and so on.