Free online WMA to SPX converter

Source format: WMA

WMA stands for Windows Media Audio, an audio format developed by Microsoft. It is commonly used on Windows systems, in older media libraries, and in files distributed for playback in Windows Media Player or other compatible audio software. WMA files are often used for music, voice recordings, and compressed audio archives. Depending on the variant, WMA may use lossy compression for smaller file sizes or, less commonly, lossless encoding.

Target format: SPX

SPX is typically an audio file encoded with Speex, a speech-oriented codec designed for efficient compression of voice recordings. SPX is mainly used for speech, voice notes, VoIP recordings, and low-bitrate audio where intelligibility matters more than full music fidelity. Its advantages include small file size, good speech quality at low bitrates, and support in applications that handle voice-centric audio workflows.

How to perform the conversion

The most reliable way to convert WMA to SPX is to use desktop audio tools that can decode WMA and encode Speex. A practical option is FFmpeg, which supports both formats in many builds.

1. Install FFmpeg if it is not already available on your system.
2. Open a terminal or command prompt in the folder containing your WMA file.
3. Run a conversion command such as ffmpeg -i input.wma -c:a libspeex output.spx.
4. If your FFmpeg build does not include Speex encoding, you may need a build with libspeex support or another audio editor that can export Speex.
5. Test the resulting output.spx in a compatible player or speech application.

If you prefer a graphical workflow, some audio editors can open WMA and export to Speex/SPX through File → Export or File → Save As, depending on the program. You can also convert the file on 101convert.com for free, without installing any software.

Notes on quality and compatibility

WMA to SPX is usually a lossy-to-lossy conversion, so some audio quality loss is expected. This is especially noticeable if the source WMA is already heavily compressed. Because Speex is optimized for speech, music or complex audio may sound worse after conversion, even if the file size becomes smaller.

Compatibility is another important factor: SPX is not as widely supported as common formats like MP3 or WAV. It is best suited for specialized voice applications rather than general playback. For best results, use a moderate or low Speex bitrate for speech recordings, and avoid converting music unless you specifically need the SPX format.