[. . . ] · Mute on applicable models is ON when depressed, and OFF when not depressed. · Check all the connections are secure. Are your Volume Controls adjusted correctly? [. . . ] Are you receiving an Audio Signal? · Connect your speakers to an alternate audio source, such as portable CD player or Walkman to determine that your speakers are working. Have you set your DVD player or Sound Card model to multi-channel? · For some DVD players, you have to go to the setup menu to set your Audio output model. · For compute ruse, you have to go to Control Panel Sounds and Audio Devices to setup the sound card. Please refer to your Sound Card manual. Popping/Buzzing/Humming from the System: [Diagnosis] Are your cable Connections Secure? · Ensure the input cable is snugly inserted into the input socket on the rear of the subwoofer. · Note: A slight low level of hum or vibration is normal as the subwoofer contains a transformer. Distorted, Little, or No Sound in One or all Satellite Speakers: [Diagnosis] Are your Soundcard Settings Properly Configured? · Ensure your computer has the latest soundcard drivers from the manufacturer. · Most computers contain a standard two-channel soundcard and will not require any adjustments to the speaker configuration. To optimize the sound quality from your system: · Sit in a comfortable position at the computer desktop. Take time to test the listening environment · The system will perform at it's best by using music CDs with wide frequency content and spacious left-to-right imaging. · The driver used in the subwoofer will change it's characteristics subtly over the first two weeks of use as the suspension of the cone will loosen up slightly, producing a trace more warmth to the overall sound texture. · Adjust speaker placement and Bass Volume for the most realistic imaging and tonal balance by listening to several different musical selections and game or computer sound effects. · For optimum acoustic performance, we recommend that you place your satellite speakers at least 6-8" from rear walls to reduce unwanted reflections that can muddy your sound. [. . . ] · For optimum acoustic performance, we recommend that you place your satellite speakers at least 6-8" from rear walls to reduce unwanted reflections that can muddy your sound. Bass frequencies may be enhanced or exaggerated by placing your subwoofer close to a wall or corner. [. . . ]