From Audacity Manual
- The green bars show the playback level, and the red bars shows recording level. L is the left channel and R is the right channel.
Adjusting playback level
The output volume slider on Mixer Toolbar does not affect the playback meter - the purpose of the meter is solely to indicate what the loudness of the project audio would be were you to export it as an audio file.
Adjusting and monitoring recording level
Having chosen the correct input device in Device Toolbar, use the input volume slider on Mixer Toolbar to adjust the level of audio being recorded. In the image above, note that the blue lines in the recording meter (indicating the maximum peak level attained) are at about -6 dB. This is a sensible level to aim for when recording, because it gives you headroom to make edits affecting volume afterwards.
Note that in some cases the input volume slider may not be visible, as described on the Mixer Toolbar page. In that case you will need to use your sound card's or operating system's input volume control to set the recording level in Audacity.
It is good practice to test the correct input level before recording for real. Monitoring lets you do this without actually having to record and then delete a test track. It also verifies that you are recording the input source you expect. There are two ways to turn monitoring on and off:
- Left-click on the recording meter to turn monitoring on. Click again to turn it off.
- Click on the downward-pointing arrow beside the microphone symbol to display the meter drop-down menu. Choose "Start Monitoring" or "Stop Monitoring" as appropriate.
- on Windows or Linux, unmute the playback of your input source in the playback side of the system mixer. If this does not work, enable "software playthrough" in the Transport Menu
- on Mac OS X, enable "software playthrough" in the Transport Menu. If this does not work, try the free LineIn application.
What the bars and lines mean
- CR: Current RMS Level. The right-hand edge of the lighter part of the bar. This shows the average level of the audio and gives a general indication of its perceived loudness. It relates directly to the amplitude of the light blue shading in the waveform.
- CP: Current Peak Level. The right-hand edge of the darker part of the bar. This shows the current peak level of the audio, and relates directly to the dark blue shading in the waveform.
- RP: Recent Peak Level. These lines indicate the highest peak level attained in the last few seconds. They disappear after playback or recording is stopped, or if you left-click on the recording meters.
- MP: Maximum Peak Level. The blue lines indicate the maximum peak level attained during the current playback or recording session. They remain visible after playback or recording is stopped, and are reset when a new playback or recording session is started, or if you left-click on the recording meters.
- Clip: Clipping warning. The red lines to right of the maximum value of the scale appear as soon as there are four or more consecutive samples of audio exceeding that maximum. Once they have appeared, the clipping lines remain visible throughout that playback or recording session. They are thus not an indication of current clipping, but an absolute indication that clipping occurred somewhere in the track. The lines remain visible after playback or recording is stopped, and are reset when a new playback or recording session is started or if you left-click on the recording meters.
- When playing a mono track, Audacity sends the output to both left and right speakers. Therefore if you leave the pan slider on the Track Panel untouched, both channels of the playback meter will show an identical level. If you pan towards one channel, then the opposite channel will have its level reduced until a complete pan away from it will remove it.
- If you set Audacity to record in mono (for example, from a microphone), only the left channel recording meter will be active.
Undocking and Resizing
Like all toolbars, Meter Toolbar can be undocked, but unlike the other toolbars, it can also be resized. Resizing gives longer scales for the meters and hence a more accurate view of the volume levels.
- If the meter is docked, you can resize it horizontally by clicking and dragging the right edge.
- To undock the meter, click the handle on the left edge and drag. You can drag outside the Audacity project window, too.
- To resize when undocked, click on the resize handle that appears at the bottom right of the toolbar and drag horizontally or vertically.
- When resizing vertically:
- The meters display one above the other when the toolbar height allows this, but the height is less than the width
- The meters display in vertical orientation when the toolbar height exceeds its width
Here are three examples of an undocked and resized Meter Toolbar:
|Horizontal (after dragging to right)|
|Horizontal (after dragging down a short distance)|
|Vertical (after dragging the height down in excess of width)|
The drop-down menu lets you change the meter's visual orientation, the scale format and more. You can access it by right-clicking on either the playback or recording meter, or by clicking the downward-pointing triangle in either meter.
Disable and Monitoring
- Disable Meter/Enable Meter: Turns the individual playback or recording meter off or on. When the meter is disabled it is gray and does not operate.
- Start Monitoring/Stop Monitoring (recording meter only): Starts/stops monitoring of the input (recording) level without actually recording a track. You can also start and stop monitoring by left-clicking on the recording meter.
- Horizontal Stereo: Displays the meter at its default horizontal orientation, with the bars extending from left to right.
- Vertical Stereo: Displays the meter vertically, with the bars extending from bottom to top.
- Linear: Displays the meter with a linear scale where the maximum level before clipping is 1.0.
- dB: Displays the meter with a logarithmic scale where the maximum level before clipping is 0 dB. This is the default view giving more detail for fainter sounds, corresponding more closely to how sound is heard. The minimum value of the scale can be changed in the Interface Preferences.
- Preferences: Opens the Meter Preferences window to set the refresh rate for the meters. A higher rate makes the meter show more frequent changes. Too high a rate can cause audio breakup on slower machines.