When you play music on your computer, there are several controls in different locations that allow you to adjust the volume: the player program, the system mixer, and the power amplifier. Choosing the right setting for each volume control will help minimize distortion and noise.
Most sound cards allow for multiple inputs, each with its own volume control. The system volume control has sliders that regulate the volume levels of each of the sound card’s inputs (CD, mic, player program, etc.), plus a master volume control that regulates the sound card’s output level (Figure 4-7). Sometimes the volume control of the player software also controls the system volume control. Most computer speakers also have a volume control that regulates the level of their built-in amplifiers. If your computer is connected to your stereo, use the main volume knob on your receiver to set the speaker volume.
The Windows Volume Control program controls the input and output levels of the sound card and has separate screens for recording and playback levels. The Playback Control screen has a slider labeled “Wave” (or “Wave/Direct Sound”) that sets the input level of the audio coming from your player program. The slider labeled “CD” controls the input level coming from an audio CD played in your CD-ROM drive.
A master-level control (labeled Play Control, Speaker Control, Master Out, or Volume Control) sets the output level of the sound card (which is the same as the input level fed into the power amplifier).
To access Windows Volume Control, double-click the speaker icon in the system tray. If the icon is not visible, you can launch the Volume Control program via the Start menu, by selecting Programs → Accessories → Entertainment → Volume Control.
On Macs, the volume control can be accessed through the player program and through the “Sound” option located under System Properties in Mac OS 9.2 or under System Preferences in Mac OS X. In Mac OS X, you can also adjust the sound level by clicking on the “Sound” icon on the righthand side of the menu bar. The slider control (sometimes labeled “Output Volume”) adjusts the playback level. The keyboards on some newer Macs also have volume-control keys built in. These volume-control keys are linked to the Output Volume slider and vice versa. The volume control within iTunes is independent of the system volume control.
The key to minimizing noise is to keep the signal level as high as possible as it passes through the sound card without overdriving the audio circuits. The speaker volume should be turned up just high enough to reach the loudest undistorted volume that you would normally listen to.
Here’s how to set your volume controls for the best sound:
Set your player volume control to 100%.
Set your input volume control to 100%. (The input slider is labeled “Wave” in the Windows system volume control shown in Figure 4-7.)
Set your master volume control to 70%. (The master slider control is labeled “Volume Control” in the Windows system volume control shown in Figure 4-7.)
Turn the volume on your speaker (or stereo receiver) all the way down.
Play the loudest song that you would normally listen to.
Gradually turn up your speaker volume until you begin to hear distortion.
Reduce the speaker (or stereo receiver) volume level slightly, until the sound is clear.
Regulate your listening level by using the master volume control.
The volume control in some player programs (such as Media Jukebox) is linked to the master system volume control. In this case, you can use the player volume control to regulate the volume. Multimedia keyboards that have volume up and down buttons also control the master system volume control.
Sometimes it’s more convenient to use the player program’s volume control than to use the master control, even if they aren’t linked. It’s okay to do some volume adjustment here, as long as the levels are kept fairly high. After following the above procedure, reduce your player volume control level to about 75% and play a song of average volume. Adjust the speaker volume as necessary to reach the desired loudness. You can then adjust the player program volume control from about 50% to 100%, as needed for songs of varying levels.