Figure 2: Making a selection.
First, make sure the selection tool on the toolbar is selected. If not, click on it. Now press and hold the left mouse button and drag the mouse to mark the area with silence. You can extend and contract selection by holding down the Shift button and clicking on the area.
Note: Use and to zoom in and zoom out. After you select silence, remove it using the Edit-> Delete menu or by using Ctrl+K key combination. To see all the sound, press the (Fit project in window). In the same way remove silence at the end of the sound.
Figure 3: Audacity preferences.
Sound is post-processed but before you save it you have to change WAV format preferences. To do this, open the Audacity Preferences window by using the Edit-> Preferences... menu or by using the Ctrl+P key combination. Select File Format tab and Other... from the Uncompressed Export Format list. To save a file in a WAV format with 24 bits depth select WAV (Microsoft) as Header and Signed 24 bit PCM in Encoding. Finally save the file using the File-> Export as WAV... menu.
How to convert digital audio files?
In the previous paragraph we adjusted an audio file by removing fragments from the beginning and the end. This archive version will be used to prepare a web delivery version in mp3 format by using the LAME encoder.
As you can read at the LAME home page, „LAME is a high quality MPEG Audio Layer III (MP3) encoder licensed under the LGPL.” LAME is distributed as a command line tool. In addition to a console tool LAME is supported by many programs, usually with a graphic user interface. A complete list of software which supports or uses LAME can be found here. Find and install the version appropriate for your operating system. In this description we use Windows binaries for version 3.98.4 downloaded from RareWares.
Before you start conversion to the mp3 format, here is the basic information about the mp3 encoding modes: