OK, I'm not much of an audiophile so forgive me if I don't describe this problem very well or it's something I should know.

I have a stock 2009 Civic LX with manual transmission (bare bones package so no navigation or anything). I'm not sure if this is an issue I bought the car with or it developed after I bought it, but I've only driven it for ~6k miles. Anyway, when turning the volume up it seems to actually get quieter from 33-40 (max). It does this MOST of the time but sometimes it seems to go away.

Can anyone explain to me what's wrong?

 

well most radios you dont crank to max, typicaly anything over 75% usually sounds crappy and distorts alot and just sounds bad. i dont recomend cranking it to max.

 

That may be true but I'm still at a loss for the problem.

 

bring it to the dealer...im sure it is an issued that will be covered under the warranty.

 

I mentioned it to them when I took it in for it's first service after buying it. They said there was nothing wrong with it and the guy tried to give me the runaround and said they will do that to prevent damage.

Do you know if they check it with a computer or something like that similar to the way the check the other components?

 

i highly doubt it... the dealership wont scratch there own @ss if there computer doesnt tell them to and how to.
i doubt its actually a problem. if you want louder try a nicer aftermarket radio or go big and amplify your internal speakers with a nice 4channel amplifier.