This is a free container audio file. This format allows you to store compressed audio information. Files of this format can be played by any media player that supports OGG, such as Windows and Unix players. It can utilize one of several encoding schemes. The format was developed by Xiph.Org. Its full name is Ogg VorbisAudio.

spx

An audio file with recorded voice messages

This format extension is one of the Speex Audio formats. It is an open-source codec developed by Xiph.Org. Used for creating voice messages and transmitting voice over packet-based networks with a low level of security. It is an audio file with recorded voice messages that are packaged in an OGG file. Only certain media players can open it.