The beautiful, gentle sound of a music box can instantly call up memories of childhood or create a special atmosphere. It would be costly to buy a new music box every time you wanted to hear a new song -- and a lot of contemporary songs can't be found on music boxes, anyway. Don't worry: With some computer software, you can make any song sound like a music box, even the most up-to-date hits.
Download and install your sequencing software. Follow the instructions to set up the audio on your computer, or use "Tools ---> Audio Options" or a similar command.
Create a new MIDI file in your software using "File ---> New ---> MIDI" or a similar command. Open the MIDI file of your song using "File ---> Import ---> Import MIDI File" or similar command. See if the file has opened in several tracks, in which case it is a multitrack file, or in one, in which case it is a standard file. Play the file.
Delete the drum sounds if present; music boxes do not have drums. If there is a separate drum track, delete it. If you have a single track, double-click on the track so you can see the MIDI notes and delete the drum pattern.
Open a VST synthesizer in your sequencing software. Find the "Track Insert," which is often to the left of the track, click on it and use the menus to select a VST synthesizer. Make sure the VST synthesizer is set to the same channel as your MIDI track. Solo the track if you have several tracks open by clicking the "Solo" button, or similar command, to the left of the track. Click the "Play" button at the bottom of the sequencer window to play the song.
Find a music box sound on your VST synthesizer. Click on the VST synthesizer icon or menu to the left of your track, and use the menus in the synthesizer to choose the right sound. Use the music box sound if you have one, or use a similar sound such as glockenspiel. Insert the same VST synthesizer on the other tracks if it is a multitrack file, and select the same sound.
Listen to see if the song is playing too fast or too slow. If it is, change the tempo of the song until it sounds right using "Tempo Control," or a similar command, on the transport bar at the bottom of your sequencer. Change the volumes on the left side of the tracks if needed until it sounds good. Delete any tracks or notes you think don't sound good; you can leave only the melody if you prefer.
Check the law in your country on reproducing commercial music. It is legal in many countries to use MIDI sequences for personal use, but distributing your song may be illegal.