Firelight Technologies has made its audio tool suite FMOD Studio completely free for indie devs, regardless of whether you're using it for commercial purposes or not. The tool set has always been free to download and use for non-commercial projects, but as of today, you can now utilize it for your commercial projects too. FMOD features Unity integration, a plugin SDK for creating sound generators and effects, and an all-in-one multitrack editor for interactive music and sound effects. The tool set has been used in multiple AAA games in the past, including Forza Motorsport 5. While Firelight didn't expand on who exactly it classes as an "indie developer," the company's CEO Brett Paterson noted, We started out as an indie company so we've always felt an affinity with the indie community... We wanted to give back to that community." [Update: The official FMOD Studio Twitter added that the offer is available "absolutely free for budgets under 100k." Gamasutra has contacted FMOD for additional information.] You can download FMOD Studio for free from the official website.