Power switch is not in ON position. Move switch to ON position and check that the LED indicator illuminates.
If using battery power, check that the batteries are inserted correctly. Battery polarity marks (+/-) must match the polarity marks (+/-) printed on the battery compartment.
Replace all batteries with fresh AAs. Move power switch to ON position and check that the LED indicator illuminates.
Verify that product is receiving power. See above steps.
Make sure volume is loud enough to hear.
Make sure all cables are connected properly and securely.
Test the speaker with a different audio source. If other source produces sound, problem lies with first audio source.
If using WAV and MIDI files, please note that they can be of poor quality compared to modern MP3 files. This distortion can be easily noticed on high-powered speakers.