It was a no-brainer for Sam Witwer to agree to playing Darth Maul on Star Wars: The Clone Wars. He said yes to Dave Filoni even though he wasn't entirely sure how he would play the character or even how the sliced and diced Sith Lord would make a realistic comeback.
Maul wasn't Witwer's first foray into the Star Wars universe. He voiced Starkiller and Palpatine in The Force Unleashed, and he dipped into the Dark side of the Force as the Son in the Mortis trilogy during season three of The Clone Wars. He actually tied some of the Son's dialogue to the mad ravings and mutterings of Maul when he is first found in his cave.
He incorporated some of the Sith Code, too. He wanted to show the constant struggle that is going on below the calm surface inside all those who follow the evil side of the Force. Maul has no filter and no control; what we see when we encounter him again is a glimpse of the turmoil of emotion – including madness – that the Sith have to fight. It's easy for them to imprison themselves in their thoughts.
When he took his first stab at bringing the Sith Lord back to the galaxy, Witwer just went for it in the recording studio. He wanted to show the character's struggle and he had to make up what Maul was mumbling. He just said a bunch of crazy stuff. When he finished, he didn't hear anything from the other side of the glass immediately. He didn't think it was a good sign, but after about twenty seconds, Filoni buzzed in and said, “Sorry Sam, we're just discussing my great wisdom in hiring you.”
As far as inspiration for the voice, it was a little tricky. One thing that actually made Darth Maul memorable to me was his overall silence during The Phantom Menace. He just didn't have a lot to say. It made me feel like he was very calculating and cautious. He's different now, but he's gone through a drastic change. He couldn't bounce back from what we went through and be the same character we knew. He might get there, but it will take a while.
Anyways, Witwer did draw from Peter Serafinowicz's few lines of dialogue. He said he had to; Serafinowicz's lines from the trailer made such an impression. He also wanted to add some of Ray Park's physicality to the voice. Since Maul doesn't have complete control of himself yet, Witwer pointed out that the physicality would seep through into his voice.
It was very apparent that Witwer has given the character a lot of thought. He knows that it would be bad storytelling for Maul to be just as he was the last time we saw him. I'm looking forward to seeing Maul's fight to get back to what he believes is his rightful place in the galaxy and to see his quest for revenge against Obi-Wan.