This format was developed by Creative Labs for storing and transmitting audio information of 8 and 16-bit sound cards. VOC can be represented as a sound effect, a music sound or a sound clip. It consists of a header and a pair of blocks containing the sound data. This format is supported by several audio players. VOC files can be converted into the WAV format using various utilities.

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.