By Chris Emma–

LAKE FOREST, Ill. (CBS) — Noise seems to be a constant now in Bears practices.

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It’s chirping from the defense and its new leaders, linebackers Danny Trevathan and Jerrell Freeman. It resonates with the rest of this rising unit. Like Trevathan said, that new swagger will spread like wild fire. This is just the beginning.

“It’s a different group,” Bears quarterback Jay Cutler said of the defense. “It’s a much different group. They’re faster, they’re quicker, they have a confidence about them.”

One year ago, the newly signed Pernell McPhee took charge of the Bears’ defense and their new identity. McPhee said that he wanted “dogs” on the defense.

McPhee made an impact when healthy but struggled with a knee injury for the second half of the season. Even if he was healthy, it wouldn’t have been nearly enough. Defensive coordinator Vic Fangio brought the Bears competence in a rebound from catastrophe, but they still ranked 14th in yards per game allowed and 20th in points per game allowed. The main problem was that they forced just six fumbles and recorded only eight interceptions.

At the very least, the Packers weren’t posting historic numbers on the Bears defense last season. But the unit benefited from complementary ball from the offense.

Frankly, the Bears defense couldn’t be counted on to get off the field. Their leader in interceptions was cornerback Kyle Fuller, who had two. Nobody else had more than one. They couldn’t earn takeaways and often struggled to force punts. This put pressure on Cutler not to make mistakes, knowing that the defense couldn’t hold its end.

The Bears were often left controlling the clock on offense in order to minimize damage to their defense. Combined with injuries to key playmakers — especially receivers Alshon Jeffery and Kevin White — the Bears had few options to hit a home run on offense. In turn, they played a careful, conservative game plan that served the defense well.

In 2016, Cutler will look to air it out more, of course only if provided with a healthy complement of receivers. The Bears seem to have boom-or-bust potential offensively — injuries being the biggest variable — though Jeffery and White could provide Chicago with a high-octane system.

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Complementary football can be a wonderful concept when an offense, defense and special teams unit are clicking together. The Bears should be able to count on their defense to take the football away and get off the field in shorter order much more often in 2016. Perhaps this could become a top-10 defense this season.

“They’re going to help us out,” Cutler said. “Get some short fields, get some turnovers, put some pressure on us to do our job on offense.”

Defensive lineman Akiem Hicks made his goal for the defense more concise: “To crush everybody.”

It starts up front with the wrecking balls in Hicks and Eddie Goldman, who should create disruption. The two can play off each other well. The Bears have edge rushers in McPhee, Lamarr Houston, Willie Young and Leonard Floyd who can get to the quarterback and perhaps the best inside linebacker tandem in football in Trevathan and Freeman. The Bears have questions in the secondary, though the front seven can bring stability with steady pressure.

During their first year together, Fangio and the Bears defense were just OK — good enough to compete but not quite enough to win games. The Bears failed to impact games with sacks, fumbles and picks, so they went out and added talent.

After receiving his Broncos Super Bowl ring during mini-camp, Trevathan showed to any teammate he could find and explained that they would win one with the Bears. Trevathan fits well with McPhee, Freeman, Hicks and the new demeanor of this defense.

Make no mistake, there’s most certainly a new swagger for the Bears defense. You hear it each day at practice, starting with Trevathan.

“You can always finish strong,” Trevathan said. “I want these guys to know I get their back. We’re going to go to work, we’re going to get it done.”

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Chris Emma covers the Bears, Chicago’s sports scene and more for CBSChicago.com. Follow him on Twitter @CEmma670 and like his Facebook page.