Instructions
Open a Web browser and navigate to the Free-codecs website (see Resources for link). Type "Atrac3" in the codec search bar and click the "Search" button.
Click the "Free-Codecs.com : Download Sony ATRAC3 Audio Codec 0.98" link, followed by the "Download Sony ATRAC3 Audio Codec" link to download the codec zip file.
Double-click the ZIP file to extract its contents. Double-click the extracted atrac3.exe file and follow the onscreen instructions to install the codec.
Open a Web browser and navigate to Goldwave's Web page (see Resources for link). Click the "Download" link followed by the "Download" button to download the install file. Double-click the install file and follow the onscreen instructions to install the application onto the computer.
Double-click the Goldwave program icon to launch the program. Click the "Open" button, locate the audio file that you want to convert to .AT3 and double-click the file to add it to the program.
Adjust the start and end track markers until the desired one-minute audio section is selected. Click the "Edit" menu and select the "Trim" option.
Click the "File" menu and select the "Save As..." option. Type a name for the file in the space provided and select the "Wave (*.wav)" option from the "Save as type" drop-down menu.
Select the "ATRAC3 66kbps STEREO" option from the "Attributes" drop-down menu. Click the "Save" button to save the file.
Locate the .wav file you saved in step eight on the computer's hard drive. Click the "Tools" menu and select the "Folder Options..." option.
Click the "View" tab and remove the checkmark next to the "Hide extensions for known file types" option. Click the "OK" button save the changes.
Click on the .wav file's file extension to highlight it and click on the highlighted file extension to edit it. Change the file extension to ".at3" to finish the conversion process.