ACID Pro is a professional digital audio workstation (DAW) software program. It was originally called "ACID pH1" and published by Sonic Foundry, which was later merged into Sony to create Sony Creative Software. ACID Pro uses Acid Loops (meaning they contain tempo and key information for proper pitch transposition) painted out across the screen to create music tracks. Acidized loop sample CDs are available from Sony, as well as third party companies.