As he set about designing a new stadium for the Seattle Seahawks, architect Paul Griesemer juggled a series of requests and realities. Seahawks owner Paul Allen wanted an homage to nearby Husky Stadium, where fans are close to the field. A relatively tiny footprint mandated steep inclines to squeeze in 67,000 seats. Seattle's rainy weather prompted a metal covering that protected 70 percent of the seating bowl.

The result is a structure that provides the loudest and most effective home-field advantage in U.S. sports today. And to me, it yields an obvious question: Why aren't designers elsewhere emulating the conditions at CenturyLink Field -- accidental as they might have been, in some cases -- to give their teams a similar advantage? The question is especially significant, of course, as the Seahawks' NFC West rivals prepare Levi's Stadium for its regular-season debut Sunday night.

The answer is not as simple as the question. I've spoken recently with three designers, including Griesemer as well as architects for the San Francisco 49ers' and Minnesota Vikings' new stadiums, and found that psychology is as important as architecture in creating an in-house environment.

"What we usually find is that, above all else, people want a unique experience," said Bryan Trubey, whose HKS firm designed the Vikings' stadium, scheduled to open in 2016. "That's what we really focus on, to make a place that is so unique relative to the team that it's special. When you have a building that's absolutely and totally unique in every way, the response will be unique and there will be a connection made between the fan and what's going on in front of them. The quality of the environment -- which every community sees a little differently -- is a big key to [home-field advantage]."

In Seattle, science tells us that having a metal roof amplifies and redirects crowd noise back to the field. Positioning fans close to the field also raises noise levels. The stadium famously posted a Guinness World Record at 137.6 decibels last season, and crowd reaction has caused at least two recorded earthquakes.

In the big picture, the Seahawks have a .698 winning percentage at home and .392 on the road since the stadium opened in 2002. More recently, they've won 18 of their past 19 at CenturyLink, with an average margin of victory of 16.1 points. Griesemer, however, was emphatic in dispersing credit for those numbers.

"I don't know that we necessarily went into it thinking we would cause a record of false starts and all that," said Griesemer, of the firm AECOM. "What the fans there have made it into is as much or more as what we made it. The fact is they created this identity of the 12th man, and taken the framework of the stadium to create something special. That's one of those pleasant surprises that you like to be part of.

"If someone were to say, 'I'm going to replicate Seattle and replicate the same great game environment,' well, one plus one doesn't really equal two. You add up one plus the 12th man, and you get something more than 13.

"A lot of it comes down to how connected people can be to team and game environment. There is a lot of pride in Seattle that they can be influencers of the game. When you get that level of connection, it takes on a level of its own."

So how did the designers of the 49ers and Vikings' stadiums endeavor to create the same connection? Let's take a closer look.

Levi's Stadium

In deference to their location near Silicon Valley, the 49ers set out to build the most connected new stadium in the NFL. A custom smartphone app will allow fans to check traffic, order food, update statistics and view replays. There are also nine separate clubs to service the 49ers' high-income clientele.

What, then, will keep fans focused on and engaged with the game? Lanson Nichols, senior project manager at HNTB, pointed to a series of features. The 49ers will have more seats in the lower bowl -- about 45,000 -- than any other NFL stadium. Fans in the first row will be as close as 17 feet from the back of the sideline.

Most notable, however, are the open concourses that give fans a full view of the field as they walk to bathrooms, concessions and most other destinations. During preseason games, fans gathered along the rails of the lower concourse facing the field to create impromptu standing room areas.

"People really lined the edges of the concourse, the rails, standing and watching the games," Nichols said. "It brought a lot of people closer to the field. Two- and three- people deep all the way around the edges of the concourse. I think it will make a big difference in terms of people's engagement.

"You talk about noise, but you also have to talk in a larger sense about the presence of the fan. It's about giving them the ability to engage and observe and participate in what's going on on the field."

And in Minneapolis …

The Vikings' as-yet-unnamed stadium will benefit from the advantages of a fixed roof, much as the notoriously raucous Metrodome did from 1982 through 2013. About 60 percent of it will be built with a clear synthetic polymer commonly known as ETFE, and the rest will be metal.

ETFE hasn't been used much in American stadiums, but Trubey said "it's a more acoustically reflective material" than the Metrodome's fabric roof. "It should make the stadium louder" as a result, he added.

Meanwhile, Trubey's efforts to engage fans by positioning them close to the field took a unique turn. The first row of seats will be elevated an average of seven feet off field level, about twice the industry standard.

"A lot of these buildings, the first three or five rows are too low and people there can't see too well," Trubey said. "To us, that makes a critical difference in terms of how people are connected. When the first five rows don't feel connected, that really has a powerful effect on the excitement of fans all the way up. On the other hand, if the fans closest to the field are engaged, it will have a domino effect."

It would be fruitless, all three designers agreed, to copy the CenturyLink blueprints and expect an identical result. In this case, architects are like coaches. Their job is to put fans in position to impact the game. The rest is up to them.