The ear-splitting, earth-shaking noise at CenturyLink Field makes the Seahawks’ already-fast defense seem faster, their fierce pass-rush fiercer. The offensive line’s ability to keep away from penalties and keep Mark Sanchez upright may well decide if the Jets escape Seattle with a win Sunday.

The loudest outdoor stadium in the NFL has helped the Seahawks force the most false starts in football. The Jets have blasted music at practice and are preparing to lean even more heavily on silent snap counts and hand signals, and trying everything to brace and prepare for the noise.

“[If] teams can get a bead on your cadence, it really plays into that defense’s hands,’’ coach Rex Ryan said Friday. “They’re built to rush the passer. They have two really explosive edge players and then they have some good pass rushers inside.

“The communication is critical. The self-inflicting wounds — their home field contributes to them, but we can’t allow them. Our focus has to be so tight, so detailed that we don’t allow it to affect the game or control the game.’’

Seattle’s defense has been the NFL’s fourth-stingiest — allowing just 138 points — largely by putting quarterbacks under siege. Right defensive end Chris Clemons has seven sacks and 15 quarterback hits, with rookie Bruce Irvin adding five. And their home-field advantage — second-best in the NFC since opening CenturyLink Field — is real.

The 113 false-start penalties Seahawks foes have committed since 2005 are the most in the NFL. The stadium has reportedly reached a noise level of 137 decibels — for perspective, a Boeing 747 cranks out 130 — and the crowd’s reaction to Marshawn Lynch’s 67-yard touchdown run in the Seahawks’ 41-36 playoff win over the Saints on Jan. 8, 2011 measured the shaking equivalent to a small earthquake, according to the Pacific Northwest Seismic Network.

“You turn it up as loud as you can, and it’s brutal,” Ryan said. “You try to get it to be as loud and as crazy and as hectic as you possibly can.

“Then, when you get there, the thing you can’t simulate is how they’re literally on top of you.That’s something that you really can’t get ready for.’’

The Jets have to be sound in pass protection, especially against Clemons and Irvin. Getting off schedule and putting Sanchez in third and long is the sort of thing that leads to turnovers, with Sanchez’s rating falling to 50.6 on third-and-nine or more.

“They’re fast, explosive, they get up the field, the quarterback has to be ready to step up, move in the pocket,” said Tim Tebow, more concerned about the Seahawks than their crowd, saying he thought LSU was a louder environment. “They have a lot of great athletes. …They usually get quarterbacks flustered with their speed,’’

“I’ve never been to Seattle, but college stadiums compared to the NFL, there’s not much of a comparison. Pretty much most of the SEC places are a lot louder.’’