Your woofer could be obstructed by something. Take the protective grill off of the front to make sure nothing is touching the driver. Also, check the hole on the back of the speaker casing to make sure there is no debris in there.
If nothing is obstructing the speaker, check to make sure the speaker is correctly connected to the motherboard. To access the motherboard, simply unscrew the large plastic cover on the bottom of the iHome system and remove the cover. Once the cover is off, make sure all the wires are connected correctly to the motherboard.
If everything is connected correctly, and nothing is obstructing the speaker, the speaker may be the problem. Visit the iHome iP1’s device page to view the guide on how to replace the woofers.