Keeping an ear tuned to a fat collection of music files and an eye on your PC's ever-diminishing hard drive space? Then give Audio Dedupe ($30, feature-limited free demo) a try. It uses a sophisticated set of tools to find duplicate music files, even if they're in different file formats.
Audio Dedupe doesn't merely compare file names or file sizes to find duplicates and similar files. Instead, it compares the contents of the audio files themselves to see whether they are duplicates or similar. You can even control the amount of similarity you wish to flag, such as 70 percent. The program then goes about its work--although if you have a lot of audio files, be prepared to wait. On my collection of 2000 music files, it took 35 minutes to do its work.
It lists for you files that it believes are similar or duplicates, and shows the level of match between them, with 100 percent being a duplicate. It will even list files as 100% duplicates if the same audio is in two different file formats, or if it has different names. Audio Dedupe includes tools for listening to the files as well. After you find similar or duplicates, it can delete them for you. Note that this download is a demo; it lists only the first ten pairs of duplicates, and will not delete any files. To get the full capabilities, you need to register the paid version.
Author MindGems offers a free program, Fast Duplicate File Finder, which performs a similar task, but doesn't have sophisticated tools for finding similar audio files. If you want to find duplicates of exact file names only, you probably can get by with the free Fast Duplicate File Finder. But if you want a sophisticated way to clean out similar audio files, Audio Dedupe may well be worth buying.