This is an usual thing with the whole sound sistem; you will see that the sound will get better and better...they just need the time;
but, if you want to reduce the time of the running in, you can buy a special cd that puts the whole speaker sistem to work, in a very big area of frequency...try to get from an audio equipement dealer or something like that; it is the same if you wait (usually, if we exclude the special spakers>subwoofers); the normal time for the running in of a normal speaker is about 50 hrs. After that, wyhiwyg!
(what you hear is what you get)
if u can't love your alfa,
you can't love anything...