Several readers have written to ask if there is a way to convert digital music files from one format to another, such as from WAV to MP3. Well, there are a number of sites that offer programs for making such conversions, with prices ranging from free to about $50. Some convert files at fixed compression ratios while others let you choose a compression ratio for the finished file.

Lower compression results in better sound quality, while increaed compression cancels out certain frequencies to conserve disk space. The results may sound fine to one listener, but inadequate to another. You can experiment and choose the ratio that works best for you.

Several of these programs can be downloaded for a free evaluation period, and if someone can recommend a favorite I will mention it here. I don't have the resources to personally evaluate all these programs, but am quite happy with the free one from www.processtext.com. Others can be found by typing something like wav to mp3 converter into Google.com. The free one I chose doesn't offer compression ratio (bit rate) choices, so converted files tend to be quite large. However, this works for me since I have plenty of disk capacity on my computers and MP3 players.

The reason many folks want to convert WAVs to MP3s is that WAVs are not recognized by most portable music players, such as the iPod. Many of the WAV files Ed wants to convert are songs found on this site (Don's Music Pages), where there are hundreds of mid-20th century "swing era" pop and country favorites. These are songs I've found on other sites or which readers have sent me via email. Most are WAVs and MIDIs — but some are MP3s, while others are in the ASF (Advanced Streaming Format) or WMA formats. Since I am not personally into audio file editing, I have simply copied the files "as is" to my site's music pages.

I can't explain the technical differences between the various audio formats, but I can offer a brief overview of their origins.

In the early days of computers the only sounds available were beeps and pings that accompanied certain keyboard commands. These MIDI (Musical Instrument Digital Interface) files were normally created with an electronic keyboard connected to a computer. Improved technology has made it possible to create MIDIs that beautifully reproduce the entire sound spectrum of the most sophisticated keyboards.

The WAV (Waveform Audio) format was developed to provide recorded analog musical sounds, such as the harp glissando heard when Windows starts up. Users can create their own WAV voice and/or instrumental files with Windows' built-in Sound Recorder tools.

WMA (Windows Media Audio) files are usually created by "ripping" songs from commercial music CDs. The free Windows Media Player has built-in ripping capabilities.

The MP3 (MPEG-1 Audio Layer-3) eventually became a "universal" format that works on most computers and media players.

All the various audio formats can be burned onto CDs, but this does not mean they can be played via all CD players. Older players were designed to play only commercial music CDs and do not recognize computer-generated audio files. However, many of the newer players are designed to play MP3s. Read the fine print when choosing a boombox, a car stereo, or an MP3 player.

As for downloading songs from my site, detailed instructions are included on the various music pages Swing Era Popular Songs, Country Standards, Gospel & Patriotic Songs, and LatinAmerican Favorites, among many others.