|Manchester United have appointed an acoustic engineer to try and find out why singing at Old Trafford does not carry to all areas of the ground.
The sound specialist has attended one game this season and will gather information at others in an attempt to pinpoint the problem.
Noise levels at the stadium have been derided by opposition supporters and United fan groups.
One fan group said a "safe-standing" area would fix the issue.
A spokesman for the Independent Manchester United Supporters Association said such areas would allow those who wanted stand to do so and as a result would improve the level of singing and chanting.
He said: "For many, many years now, fans have been told to sit down, shut up and take what they are given.
"Well now they are sat down, and they have shut up - and the club don't like it.
"Fans are allowed to stand at moments of high excitement [but] when they are forced to sit - as they often are at Old Trafford - they make less noise.
"They should also look at having a section of the ground where like-minded fans could be in the same place, because we recognise standing is an issue for some and not for others."
He added that the club also needed to "turn the music off before games to give fans a chance to make some noise themselves".
The club has previously tried to relocate away supporters in order to create a section for supporters who wanted to sing, but that was met with opposition from police over safety issues.
A club spokesman said discussions were ongoing but the need to relocate season ticket holders in order to create any such section meant it could take several years to create.