Based on your question, it sounds like you are saying that you had a box that wasn't ported and you had a port put in it....is that the case? If so, that is probably your problem. are the subs designed to work in a ported box? Is the internal air space correct? If so, you might want to play around with box placement. Try moving it around to see where it sounds best. Also, ported boxes are "tuned" to a certain range of bass, meaning that they sound louder in that range. if you music doesn't hit in that range, it wont sound as loud.