Mixer Toolbar
From Audacity Manual
- Output Volume Slider: Sets the playback volume.
- Input Volume Slider: Sets the recording volume.
Output Slider
This is the left hand slider that lets you control the volume at which you listen to the mix of your project. This is a "monitor" control, and does not affect level of your mix, so will not help if your mix is clipped. It does not affect the levels indicated by the playback meters.
Should your output sound distorted, this is not the first place to look. Usually the distortion comes from clipping of your project's mix. You actually need to reduce the level of your tracks. It is suggested you reduce every track by the same amount using the gain sliders in the track panel.
Input Slider
This right-hand slider controls the level of the input selected in the Input Selector. If the Input Selector is not visible you will need to choose your input in Devices Preferences. Inputs can also be chosen in the operating system mixer or in any control panel that the sound card may have. The Input Slider should then control that input.
After selecting the required input source, use the input slider in conjunction with the recording level meters on the Meter Toolbar to set the correct recording level before starting to record for real.
If your input sounds distorted, lower the input slider until no distortion can be heard, also making sure the clipping indicators on the red recording meter do not light up.
Precise Volume Adjustment
Double-clicking on the input or output volume slider will bring up the Input Volume or Output Volume window. Here you can make much more precise adjustments with the slider or enter a value in the text field. You can also set a keyboard shortcut to bring up either of these windows.