A long-standing attempt to generate a better atmosphere at Old Trafford means 1,500 supporters will be located in the area normally reserved for the away contingent.
An anticipated 6,000 following from Sociedad has created the space for an initiative being spearheaded by various fans' groups and given official sanction by the club.
That the area was heavily oversubscribed when tickets went on sale suggests there is an appetite for such a scheme, even if the desire for a permanent singing section has met with resistance.
"For the big games, the atmosphere at Old Trafford is up there with the best of them but, as with most grounds, that is not the same for the lesser matches," said Andrew Kilduff, co-founder of Stretford End Flags, which has been responsible for the distinctive banners in the stadium.
"The problem is not lack of singing but more that, because of the size of the stadium and the acoustics within it, the sound doesn't travel.
"You can have fans in different parts of the stadium singing different songs at the same time and none of them really being heard.
"The idea is to have an area of the ground where like-minded fans can be in the same place and, generally speaking, make some noise."
United employed their own acoustics experts in a bid to generate more noise and studies have found the most suitable areas to be the corners of the stadium opposite the Stretford End, where the roof is lower, trapping more of the sound.
However, an initial idea to relocate away fans to the highest section of the Sir Alex Ferguson Stand was rejected by police amid safety concerns when the likes of Manchester City, Liverpool and Everton visit.
Without substantially increasing the space for away fans, moving them anywhere else from their present position would require major building work.
Nevertheless, fans' groups feel the singing section idea is one worth persevering with and are keen to make a positive impact tomorrow.
"We would encourage supporters to get to Old Trafford 25 minutes before kick-off so we can make some noise as the players are warming up," said Kilduff.
"Hopefully that atmosphere will transmit back to the players and it will improve their performance as well.
"We are aiming to police the area ourselves and hopefully, if it goes well, the singing section is something we can try again later in the season.
"Having it on a permanent basis is not as easy as people think.
"Nevertheless, if it works, it is something the club may look at because it will have a positive benefit for everyone."
Man Utd v Real Sociedad is on Sky 1 as well as Sky Sports 2 Wednesday night