Nobody likes hearing noise on their audio tracks. It's disruptive and can completely spoil soft dialogue or quiet music. Most of the time, background noise on a track is actually a part of the audio recording, in which case the popular VLC Media Player can help you to minimize it. Otherwise, the noise indicates a software or hardware problem on your computer, and to troubleshoot this you'll have to check out VLC's settings, along with other components of your system.
Adjusting Sound Levels by Frequency Band
When it comes to background noise built into the actual audio recording of a track, rather than background noise resulting from a software or hardware problem on your computer, VLC Media Player offers an audio equalizer that lets you adjust the playback sound levels for individual frequency bands. Launch VLC, then click the "Show Extended Settings" icon on the control panel on the bottom, or click on "Tools" on the menu and select "Effects and filters." In the Adjustments and Effects window, click on the "Audio Effects" tab and the "Graphic Equalizer" sub-tab. Here you can adjust sound levels for individual frequency bands, as well as try out VLC's preconfigured sound environment settings under the "Preset" drop-down menu. Click "Enable" to get started.
Experimenting With Individual Sound Levels
Begin playing the track with the background noise, and experiment with the sound levels by adjusting the settings all the way down for one frequency band at a time. A lot of background noise lies above the vocal band, somewhere between 3 and 12 KHz, although depending on the exact nature of the noise it could be anywhere on the spectrum. When you find the correct band, the background noise will evaporate. Note that some background noise occupies a wide spectrum of frequencies and may require you to turn down the sound on two or even three adjacent frequency bands to get all of it. Once you've isolated the background noise, turn the other frequency bands back up to their original level, which by default is 0 decibels. If you want, you can also partially turn the sound back up on the problematic frequency bands, to strike a balance between muting the background noise but not the actual audio signal on those frequencies.
Updating or Reinstalling VLC Media Player and Sound Drivers
If your background noise doesn't come from the track itself, then you have a software or hardware problem. If the noise occurs only on VLC and not other media players on your computer, then download and install the latest version of VLC from videolan.org. If you already have the current version, uninstall it and perform a fresh installation. This can fix many problems in the software, and may solve your noise problem completely. If it doesn't, you may be running an out-of-date audio driver for your sound card. This isn't a VLC problem, so if an outdated driver is to blame then you will probably notice the background noise when you play the same tracks in other media players. To update your sound card driver, visit the manufacturer's driver update website. The tech magazine PC World has a helpful feature on how to do this.
Changing the VLC Audio Output Module
Changing VLC's audio output module offers another solution for background noise that comes specifically from VLC. Launch VLC, click "Tools" on the menu, and select "Preferences" at the bottom. The Advanced Preferences window will open. Scroll down to the Audio section and click on "Output Modules" slightly farther down. Then click the drop-down menu on the right side of the window. It will probably be on "Automatic" for starters. Try "WaveOut audio output" first, then click "Save." Play the track and see if that fixes the problem. If it doesn't, repeat these steps and try "Windows Multimedia Device output" or "DirectX audio output." If none of these work, return it to the "Automatic" default setting.
Disabling Audio Visualizations
For audio-only tracks, VLC offers a visualizer that draws colorful patterns on the screen as the sound plays. In some instances this can interfere with the sound playback. Try disabling the visualizer to see if it fixes your problem. Click "Audio" on the menu bar, hover your mouse over "Visualizations" and click "Disable." Then restart VLC.
Checking Your Hardware Connections
This step is only necessary if you experience the same type of background noise on multiple, unrelated tracks. While this doesn't preclude a problem with VLC, a loose hardware connection is more likely. Begin playing a track and check your audio hardware connections one at a time. Don't forget to check the power cords, but pay especially close attention to the audio data jacks on your computer and on the speakers themselves -- including on the subwoofer, if you have one. To check these connections, press each plug more firmly into its jack and also wiggle it around very gently. If a loose connection is the culprit, then the background noise will change as soon as you start manipulating the faulty connection.