"I try not to," he told ComicBook.com in an exclusive interview.
"One [reason] is to approach everything fresh," Schemmel said, explaining that the subtitle version is translated by an outside translator before being passed along through another who adapts the scripts into "local, colloquial English," according to Schemmel.
"And the meaning changes slightly, so what happens to me is I watch it in subtitles, I get really married to the meaning, and then when I go in to record, I'm like, 'wait a second, that's not what happened!'" Schemmel said.
"Every once in a while [Vegeta actor Christopher Sabat] will ask me to look ahead, because I kind of need to, but for all of [Dragon Ball Z] I did neither," Schemmel explained.
Dragon Ball Super airs on Crunchyroll Saturday evenings at 7:15 p.m. CST.
Adult Swim airs the English dub during its Toonami block Saturday evenings at 9:30 p.m, and is now available to stream on FunimationNOW and Amazon Video.