Karaokize a song (mp3)

The technique to minimize the human voice and remain the music voice of a mp3, we can use Audacity (audacity.sourceforge.net).

1. Click the "down" triangle to open the menu.
2. "Split Stereo track"
3. "Mono" both track
4. Select and invert one of the track ("Effect" -> "Invert")
5. Save the MP3

Step is shown in the below picture:


[ mp3 去人聲 audacity ]

Copy Virtual Box image file

Copy Virtual Box image file

Use VBoxManage clonevdi

There are a few steps involved in order to make a copy of a VirtualBox .vdi disk file.

#1. Shut down all virtual machine and start Virtual Box main program

#2. Release the .vdi file – File > Virtual Media Manager > Select the virtual machine disk to be copied > Click “Release”

#3. Open command prompt (go to C:\Program Files\Sun\VirtualBox)

VBoxManage clonevdi c:\myvirtualdisk\Original.vdi c:\myvirtualdisk\NewCopy.vdi

#4. Add the new virtual disk image – File > Virtual Media Manager > Add

#5. Re-attach original virtual disk image to its VM

Reference: http://www.kernelhardware.org/make-a-copy-of-virtualbox-vdi/