The MPX-Player for Android

The MPX-Format


MPX is a new audio format in which the different voices of a song are available individually.
Each voice can be switched on and off individually by the listener and its volume can be regulated. The 3D spatial position and the reverb of each voice can also be changed. An MPX file also contains useful information about the song, such as: Composer, performer and included instruments.


Number of voices

20Tracks currently limits the number to a maximum of 20 voices. With more than 20 voices, the performance of modern smartphones is currently overwhelming.

Song length

20Tracks currently limits the length of the song to a maximum of 10 minutes. For more than 10 minutes, the memory requirement exceeds the capacity of modern smartphones.

Sample depth

20Tracks currently only creates 16bit songs. 24bit only makes sense if the recording was also made with 24, but increases the memory requirement by a factor of 1.5. 32bit make no sense at all as a storage format, since the accuracy is the same as with the 24bit format. Internally, however, 20Tracks actually calculates with 32bit.

Protection against change

MPX songs can be changed temporarily during playback. Voices are switched on and off and their volume changed. Each MPX song is provided with a write protection, which makes it impossible to save the changed song. For this you need a key that is only known to the creator of the file (STUDIO-ID)

Jump marks

Optical markings can be entered here in the timeline of the song. The user can then only jump to a specific point in the song. You can start the song at any point without jump labels.

Metronome track

Is a special variant of the jump labels. Every jump to any point in the song means that the song is always continued at the beginning of a bar on beat "1". As long as the user does not mute the metronome track, each start will always begin with a "count-in".

3D spatial position or panorama

In MPX songs, the instruments can be positioned in a virtual room. The user can then change his own position and walk around between the instruments. As an alternative, MPX can also assign (traditional) panorama positions to the instruments. Currently only the panorama version is implemented in 20track.

Time in bars

MPX songs that contain a metronome track also show the song position in measures.

Lossless compression

MPX files are significantly larger than MP3 files because each instrument is included individually. MPX files reduce the amount of data without sacrificing quality. Savings of up to 50% are possible. Example on a song of 2min length and with 10 voices:

If you want to create a file as small as possible, select: Sampling depth 16bit at 12kHz The file will be approx. 15MB in size

Most sensible combination: sampling depth 16bit at 24kHz. The file will be about 30MB in size

Very high quality: sampling depth 24bit at 48kHz. The file will be approx. 90MB in size