Auto Gain

Use Auto Gain to even out the volume to a consistent level across the selection. When recording a speech, interview, or telephone conversation, for example, the volume tends to vary depending on the position of the microphone relative to the person speaking. If the person or microphone moves around, the volume fluctuates. With telephone recordings, one person often sounds louder than the other.

Auto Gain automatically varies the volume level to increase it when it is low and decrease it when it is high (but it cannot correct overloaded or clipped audio).

Auto Gain Settings
Setting	Description
Target volume (dB)	Sets the final peak volume of the audio. The gain is increased or decreased so that the peak level always hovers around this value. A value close to or slightly below 0dB (100%) is recommend for maximum volume. Values less than 0dB can be used to limit or clamp the peak level to a certain volume. The "Peak reducer" preset shows how peaks can be reduced to 90% without affecting the average volume.
Update interval (s)	Sets the time between volume adjustments. Values under one second give the best results. Use a smaller value if the audio level varies quickly. Use a larger value if the audio level is mostly even already, but needs occasional adjustments.
Attack/release (s)	Sets the time it takes for the volume to change from one interval to the next. Larger values smooth out volume changes so that they are more gradual. Setting this value to zero applies the new volume instantly every update interval. Usually values less than Update interval work best. Note that when using a non-zero setting, peaks may exceed the target volume briefly as the volume gradually changes from a higher level to a lower one.
Maximum gain (dB)	Sets the maximum amount the volume can increase. Audio containing many noisy silences can result in sudden bursts of noise if the Silence level setting is not set high enough. By limiting the maximum gain, explosive volume increases for quiet sections are reduced.
Silence level (dB)	Sets the level of noise to be considered as silence. Any audio below this level is ignored and not adjusted. In other words, Auto Gain is turned off while the audio level is below this threshold. Care must be taken when setting this value. Setting it too low greatly amplifies background noise. Set it as high as possible while still getting good gain results.

One drawback of Auto Gain is that background noise is amplified along with the foreground audio. In recordings where the background noise is consistent, but the foreground audio varies, the end result will be consistent foreground audio with varying background noise. Use Noise Reduction or other Filter effects in GoldWave before using Auto Gain to reduce or eliminate that problem.

For multichannel files, each channel is processed independently. While this ensures that the channels will have the same volume level, it may produce unbalanced stereo for short update intervals. If multichannel audio is not needed, convert the file to mono or use Channel Mixer in GoldWave to mix the channels into mono before using Auto Gain.

See Also: Compressor/Expander, Maximize Volume, Presets

Change Volume

Change Volume makes the selection louder or quieter.

To make the volumes of several different songs sound similar, use Loudness instead.

Change Volume Setting
Setting	Description
Volume (dB)	Sets the relative volume. Positive values make the selection louder. Negative values make the selection quieter. A value of 0dB leaves the volume unchanged. If you are unfamiliar with the decibel scale, adjust the fader and watch the percentage value.

See Also: Auto Gain, Maximize Volume, Mute, Presets

Fade In

Fade In gradually increases the volume throughout the selection.

Fade In Settings
Setting	Description
Initial volume (dB)	Sets the starting volume. Use the lowest value to fade from silence. The volume increases to full (0dB) over the selection.
Logarithmic, Linear	Sets the shape of the fade. Logarithmic fades in more rapidly than Linear.

See Also: Crossfade, Fade Out, Shape Volume, Presets

Fade Out

Fade Out gradually decreases the volume throughout the selection.

Fade Out Settings
Setting	Description
Final volume (dB)	Sets the final volume. Use the lowest value to fade to silence. The volume decreases over the selection.
Logarithmic, Linear	Sets the shape of the fade. Logarithmic fades in more rapidly than Linear.

See Also: Crossfade, Fade In, Shape Volume, Presets

Match Volume

Match Volume makes the volumes of separate files seem similar.

This effect is considered obsolete. Please use Loudness instead.

When creating a CD, for example, you may notice that each song is recorded at a different volume level. This means you have to adjust the CD Player volume from one song to the next. By using Match Volume, you can adjust the volume levels of each song so they all have the same average level, eliminating the need to adjust the volume for each song later.

Match Volume Settings
Setting	Description
Average (dB)	Sets the overall average volume of the selection.
Allow clipping	Uses the given average level, regardless if clipping is required.
Reduce average level to avoid clipping	Reduces the average level just before processing begins to ensure that the audio will not be clipped. A lower level is used for the entire file, so the file may not sound as loud as other files processed with the same level where clipping was not required.
Abort processing if clipping is required	Processing is aborted immediately when clipping is required. A range error is displayed. Use this setting for batch processing to prevent writing clipped audio.

Use Match Volume on each file to set the Average to the same value. Use Batch Processing to apply this effect to a group of files.

Volume changes are based on a root-mean-square (rms) average. The rms average is calculated with silent regions (below -44dB) excluded. Files with similar average levels will seem to have similar overall volume levels.

To match the left and right channel levels within a single file, use the MaxMatch instead.

The average value to use depends on the files. You should open each file and display the Match Volume effect to see what average value it has, then apply an overall average value to all the files. To avoid clipping distortion, it is best to use the minimum average across all files. For example, if one file has an average of -20dB and all the other files have a higher average, such as -18dB, then use -20dB for all files.

Unlike Maximize Volume, Match Volume may result in clipping distortion if the average level is set too high. The Final peak area displays the resulting final peak level after processing. If the peak exceeds 0dB, the value is shown in red as a warning that clipping may occur. Use a lower average to avoid clipping.

This effect should not be used with Maximize Volume. Use one or the other, but not both (one cancels the other).

See Also: Loudness, Auto Gain, Compressor/Expander, Maximize Volume, MaxMatch, Presets

Loudness

Loudness sets the volume of a file to an international standard level defined in ITU-R BS.1770-4.

When creating playlists you may notice that some songs have a different volume level and you have to adjust the volume control from one song to the next. By using Loudness, you can set the volume of each song to a standard level to avoid such variations. The LUFS (Loudness Units Full Scale) number provides a way to compare and match volumes of different files. Files with the same LUFS number will seem to have to same overall volume.

Loudness
Setting	Description
Volume (LUFS)	Sets the standard volume of the selection. The standard recommends -23 LUFS, however that tends to be much lower than most songs currently available. You can scan several songs in your playlist to see the current levels, then pick one of the lower levels to use on all files.
Allow clipping	Uses the given volume, regardless if clipping is required.
Reduce volume to avoid clipping	Reduces the volume just before processing begins to ensure that the audio will not be clipped. A lower volume is used for the entire file, so it will not be at the standard volume you've given. However this ensure no distortion occurs if the volume is too high for the file.
Abort processing if clipping is required	Processing is aborted immediately when clipping is required. A range error is displayed. Use this setting for batch processing to prevent writing clipped audio.
Calculate Loudness Range	Rescans the selection to calcualte the loudness range (similar to the dynamic range). This is a much slower calculation, so it is not performed automatically. The loudness range is defined in EBU Tech 3342.

Use Loudness on each file to set the Volume to the same value. Use Batch Processing to apply this effect to a group of files.

Unlike Maximize Volume, Loudness may result in clipping distortion if the volume is set too high. The Final peak area displays the resulting final peak level after processing. If the peak exceeds 0dB, the value is shown in red as a warning that clipping will occur. Use a lower volume to avoid clipping or select the appropriate clipping option.

This effect should not be used with Maximize Volume. Use one or the other, but not both (one cancels the other).

See Also: Auto Gain, Compressor/Expander, Maximize Volume, MaxMatch, Presets

Maximize Volume (Normalize)

Maximize Volume sets the peak level of the selection. First it searches the selection for the current peak level. Then it displays the level and the position of the level within the file. You can then specify a new maximum peak level.

Change Volume Setting
Setting	Description
Maximum (dB)	Sets the new peak volume. The volume of the entire selection is changed so that the peak will match that value. A value of 0dB normalizes the volume to full dynamic range, making the sound as loud as possible without clipping distortion.

Some effects in GoldWave may cause the volume level to go above 0dB. After using many effects, you should use the Maximize Volume effect before saving a file to ensure that the full dynamic range is not exceeded. Otherwise clipping may result in the saved file.

See Also: Auto Gain, Match Volume, MaxMatch, Mute, Presets

Shape Volume

Use Shape Volume to reshape the volume envelope of the selection using Shape Controls. The volume envelope is defined by the shape line, initially horizontal at 1.0, representing normal volume. Bend or move the line to dynamically change the volume over the selection. Add a point below 1.0 to decrease the volume. Add a point above 1.0, in the red section, to increase the volume. Note that increasing the volume may cause clipping distortion. Several preset shapes are included.

The Show envelope option calculates and displays the current volume envelope of the sound. The left channel envelope is shown in green and the right channel envelope is shown in red.

See Also: Auto Gain, Crossfade, Fade In, Fade Out, Pan, Voice Over, Presets