Hard to hear voice while using iPhone 3G

I don't know if its the "ear" speaker on the iPhone or a software sound EQ thing, but I find it really hard to hear and understand people on the iPhone unless I use the stereo headset. And its not only me, 3 friends of mine with iPhones agree. I have had a Nokia and an Ericsson and the voice reproduction on those phones was very clean, whereas on the iPhone there is to much base in the voice and it makes it really hard to hear, if you are in the street with traffic forget about it.
I googeld around and have not found people complaining about this. This is not a question of the phone working, its just that the quality of the sound makes it really hard to hear.

Am I the only one to notice this or is everyone else bamboozled by the this superb phone that they are willing to overlook the fact that it has a really bad phone sound quality.

I might be just a question of EQing the sound and making it more tinny so that a speaking voice comes through better.

I like the iPhone but cant really use it as a phone unless I am in a quite place or use the headphones.

D