"It wasn't a great solution," Rosberg said afterwards in a video posted on Instagram.
The 'trumpet' was later removed from the silver car.
"It just didn't work," Rosberg explained. "It didn't make it much louder. So we'll just have to look for another solution."
It is interesting that, after all the early-season complaints about the milder engine note of 2014, fans generally rebuked the look and sound of the 'trumpet'.
One F1 fan told BBC correspondent Andrew Benson: "The notion of a special device attached to the cars purely to make more noise is so ridiculous it's offensive."
"It's an interesting moment in time for formula one," Mercedes team boss Toto Wolff said last weekend.
"Traditionally you would have said that formula one needs to be loud to be spectacular. Maybe now that's changing."
FIA president Jean Todt said he agreed to look into noise solutions - it was the governing body that sanctioned Mercedes' running of the megaphone this week - following the widespread earlier complaints.
"It is a question of taste," the Frenchman told the Telegraph last week.
"I don't have any problem with the noise, but I need to take it into account if a lot of people say they want more noise.
"But believe me, in a few months time, nobody will speak any more about the noise," Todt added.
A survey conducted by the German news agency SID found that 36 per cent of F1 fans declare that F1 is "less attractive" in 2014, while 45 per cent are just as interested in the pinnacle of motor sport as before.