Yes, before you go any further, please read Rule #8 of the Hydrogenaudio Terms of Service. The link to the TOS is at the top of every page. If you follow Rule #8, you will likely find that your MP3's don't really have more bass. If, after performing the test according to Rule #8, you still find your MP3's have too much bass, then feel free to continue this discussion.
The TOS isn't there to harass you, it's there to keep the discussions at Hydrogenaudio productive and on-topic. Following the TOS requires more work on everyone's part, but the benefit can be seen every day, in the high quality of the discusisons at HA.
Welcome to the forum!