Free online MKA to SPX converter

Source format: MKA

MKA is an Matroska audio container file. It is commonly used to store one or more audio tracks in a flexible, open container format. MKA files are often created by media rippers, audio archiving tools, and multimedia workflows that need to preserve high-quality audio, multiple tracks, or advanced metadata. Typical uses include music archives, soundtrack storage, voice recordings, and audio extracted from video files.

Target format: SPX

SPX usually refers to Speex audio stored in an Ogg container, often used for speech compression. Speex was designed for voice and low-bitrate audio, making it useful for recordings where small file size matters more than full music fidelity. It is commonly used in older VoIP systems, voice notes, and speech archives. Compared with lossless or high-bitrate audio, SPX files are typically much smaller, but they are not ideal for music or high-detail sound.

How to perform the conversion

The most reliable way to convert MKA to SPX is with FFmpeg, because it supports both Matroska audio and Speex encoding. If your MKA file contains a single audio track, the conversion is straightforward.

1. Install FFmpeg on your computer.
2. Open a terminal or command prompt in the folder containing the MKA file.
3. Run a command such as ffmpeg -i input.mka -c:a libspeex output.spx.
4. If needed, adjust the bitrate for speech quality and file size balance, for example ffmpeg -i input.mka -c:a libspeex -b:a 16k output.spx.
5. Check the resulting SPX file in a compatible player or editor.

If you prefer a graphical workflow, you can first open the MKA file in a media tool that supports audio export, then choose File → Export or File → Save as and select a Speex-compatible output if available. However, direct support for SPX export is less common in desktop audio editors than FFmpeg command-line conversion.

You can also convert the file on 101convert.com for free, without installing any software.

Notes on quality, compatibility, and limitations

MKA is a container, so the source file may hold different audio codecs. If the audio inside the MKA file is already compressed, converting it to SPX will usually require re-encoding, which can reduce quality. If the source is lossless or high-bitrate audio, expect some quality loss because Speex is optimized for speech, not music.

Compatibility is another important factor: SPX support is limited in modern players and editors compared with more common formats such as MP3, AAC, or Opus. For voice recordings, SPX can be a good choice when small size and speech-focused compression are priorities. For general audio archiving, however, a more widely supported format may be preferable.

If the MKA file contains multiple audio tracks, subtitles, or attachments, only the selected audio stream should be converted to SPX. Extra streams are not preserved in the output.