Jim Harbaugh waited, in vain, for two months to get a new sound system for the 49ers' practice field.

This week, with a showdown looming against the Lions at raucous Ford Field, it appears the Niners coach cranked up the volume on his request.

On Wednesday, two days after the Bears committed nine false starts in a 24-13 loss amid the din in Detroit, a set of rock-concert-sized speakers - each about 5 feet high and 3 feet wide - arrived at the Niners' facility.

Throughout the day, a steady stream of music - mostly classic rock (AC/DC, Deep Purple) - provided high-decibel background noise as the Niners prepped for their meeting at Detroit.

At long last, Harbaugh, who said his quest for a new sound system began eight weeks ago, felt his team could properly prepare for the type of noise that will greet them Sunday.

"You've got to be ready to be able to play without being able to talk and verbally communicate," Harbaugh said.

And a silent snap count will certainly be necessary when the 49ers play before a sellout crowd of about 65,000 that's gone ga-ga over the Lions, who are off to their first 5-0 start since 1956. Bears wide receiver Roy Williams, who spent his first five seasons with the Lions, said he's never heard Ford Field rock like it did Monday night.

For their part, however, the Niners downplayed the avalanche of noise that awaits them, noting they deal with the screaming in Seattle each year.

Rick Osentoski/AP

"Hands down, Seattle is the loudest stadium I've ever played in," quarterback Alex Smith said. "I think indoor or out, especially being a division game, it just doesn't compare really with anything else."

Said right guard Adam Snyder, "We've been playing in Seattle for a long time. We'll have to prepare this week just like we do for (the Seahawks). We have a plan to execute. It's loud everywhere."

But as the Bears can surely attest, it's not just the crowd noise that can make an opposing offensive line jumpy in Detroit.

There is also the matter of the Lions' deep and talented defensive line, which is headlined by Pro Bowlers in Kyle Vanden Bosch and Ndamukong Suh, the No. 2 overall pick in the 2010 draft. Detroit employed a nine-man defensive line rotation against the Bears and pounded Chicago quarterback Jay Cutler.

The Lions recorded only three sacks of Cutler but pressured him constantly - while rarely blitzing.

"They had nine guys active for the game and I think they rotated through all of them," Snyder said. "It's not unusual - you get a lot of situations where guys will rest the first couple downs and then come in on third down to rush the passer. It doesn't matter to us. We have a job to do and that's to protect the quarterback and open holes for (running back) Frank (Gore). And that's what we're going to do."

The 49ers' front five performed those tasks admirably in last week's 48-3 win over visiting Tampa Bay, not allowing a sack while paving the way for 213 rushing yards.

This week, though, it's likely the challenge, like the noise coming from their new speakers, will be amplified.