Manchester United's fans are too quiet. Quick! Call an acoustics expert!
The whole point of going to a football match in the UK is to make a lot of noise and cheer your team on. And if they lose, well you'll have done your best and it's all the manager's fault (as usual).
But apparently there's a problem at Manchester United's Old Trafford stadium, which at 75,765 capacity is the second-largest football stadium in the country. The Stretford Lane end of the stadium is traditionally the noisiest, being populated by hard-core Man U fans. But apparently people in other parts of the stadium can hear hardly a dickey bird.
Why this should be a new problem, I don't know. The stadium opened in 1910 and it seems to have taken 103 years for anyone to notice.
Still, better late than never and Manchester United have now appointed an acoustic consultant to analyze the problem. How much he or she is getting paid is not a matter of public record, but the last time I enquired, the going rate for a top acoustic consultant was £400 an hour. Not bad.
The wrong solution
The obvious solution to the problem, and the wrong solution in my opinion, is to amplify the fans electronically. This would be very easy to do - point some mics at the fans and hook them up to amps and speakers. Lots of them, and very powerful. But there is a huge risk that the result will sound more like amps and speakers rather than real human beings. And then some bright spark will develop the notion of playing in pre-recorded crowd effects.
It would take a high level of sound engineering system design skill to provide amplification that really did sound like a crowd, but louder. I think it could be done. But I doubt if it would be.
The right solution
The right solution, as has been known to the designers of church pulpits for a thousand years, is to contain and focus the sound energy acoustically. Imagine a stadium with just the rows of seats, but otherwise open. When the fans cheer and sing, they radiate sound in all directions. A lot of it goes to waste and only the flying creatures of the air get any benefit.
If however reflectors are installed so that sound is redirected back into the stadium, the increase in level could be significant. How significant? Well suppose that from a position at the home crowd end, the remainder of the seating occupies an angle of 120 degrees horizontally and 30 degrees vertically (roughly guessing here), then according to my rusty maths that's about 1/36 of a full sphere, therefore 35/36 of the sound energy goes where it isn't needed. Some will be reflected from the structure of the terraced seating. Making an allowance for that, I calculate the improvement in decibel terms to be...
Hang on. I'm not getting paid £400 an hour for this. But my guess is that it would be an improvement well worth having.
By the way, here's an example of an acoustic reflector at the Royal Albert Hall. They do work, you know...
Original photo: Meyer Sound
P.S. If you look more closely at photos of the Old Trafford stands, or better still actually go there, you'll see that the fans are already fairly well enclosed with reflecting surfaces. But judging from the angles, sound will be reflected mostly onto the pitch. Er.. that's where the players are. That's why the fans are chanting and singing, isn't it? To encourage the players...