The MDM-X4 is Sony's entry into the new digital four-track personal studio market. Since Sony is the licenser of the MiniDisc MD-Data format and developer of the ATRAC compression schemes, it makes complete sense that they must be a player in this emerging business.

The MDM uses a single,140Mb, 2.5 inch magneto-optical MiniDisc and has four tracks, each with up to 37 minutes recording time. You can also record in stereo for up to 74 minutes and in mono for 148 minutes. This is a "random access" recording system as opposed to a "linear", tape-based recording system so you have instant playback of any place in your song without waiting for rewinding and locating. There is complete playback compatibility between Sony, Yamaha and Tascam MD four-track machines. What separates the different machines, besides slight price differences, are the different editing and external synchronization features available from machine to machine and the ergonomic "feel" and design. This "human engineering" dictates how you personally relate to the way that the machines facilitate the recording, editing and playback of your music.

Editing features on the MDM include Song Edit, a way to do song-based editing like copying verses or chorus' and Track Edit that allows individual tracks to be manipulated. Virtual Mix allows you record more than four tracks on the MD disc for multiple, alternative takes, etc.