Back to overview Documentation version 9.23


Auto EQ section

Adjusts the spectrum without compression, making it possible to generate a very consistent sound without sounding compressed.



This filter is a dynamic re-equalizer that operates before the AGC in the processing path. Using the familiar Bands user interface found in MB1 and MB2, it can be configured to precisely match bands already in use elsewhere. Subject to user settings, this filter will attempt to keep levels in the bands at a Target level with respect to each other. Spectrum Correction is not a compressor and does not affect actual levels, overall. Furthermore, using it does not require any subsequent filters to be altered to accommodate it. If this filter is boosting the level in some band(s), it is reducing some other band(s).

Without spectrum correction, the multiband sections are responsible for two jobs: 1) Controlling audio levels, and 2) Dynamically re-equalizing incoming audio. This is usually not a problem, but it can become one on some material.

Let's say incoming audio usually produces about 10dB of gain reduction in MB1 and all bands are roughly equal in the amount of gain reduction they're doing. Now a song comes along that has very little high end. The top band of the multiband section will release and could end up doing almost no work at all. That is suboptimal, because the multiband now has no margin of error. If the amount of highs drops even further, there's nothing the multiband can do to correct it, and the audio will become muddy and dull. That's where spectrum correction comes in, to fix material that is imbalanced before it hits any further filtering. When audio is playing that is properly balanced, per the settings, this filter will have virtually no effect on the audio. When doing large amounts of correction, the filter should be unobtrusive. It simply fixes the audio relatively slowly while attempting to be as transparent as possible. The user interface for this filter resembles the multiband compressor UI, but has some important distinctions. When the filter is doing no work, you'll see nothing in the interface (no colored bars). Bars stretching to the right, in shades of blue indicate a boost in level. Bars toward the left, in shades of red, indicate a cut to the volume in that band.

The Auto EQ documentation was written by Wes Keene

Main panel


  • Enable Auto EQ
    Enables Auto EQ.

Speed panel

Adjusts the Auto EQ response speeds.

  • Adjust time
    The speed at which bands can move up and down in relation to the incoming audio.

    Unlike a compressor, running Auto EQ at a faster speed does not make audio more dense. It simply corrects spectral imbalances more quickly. Extensive listening and watching will assist in figuring out the best speed.

  • Kick speedup
    Relative response speed to spectral increases in a band.

    After the filter has increased level in a band, a loud sound might kick in which causes the filter to need to reduce it again. Sometimes, that correction might seem too abrupt. This control allows that downward correction to be slowed down and potentially sound more natural. Lower values correspond to slower downward correction.

Abrupt changes panel

Protects against loud bursts due to abrupt spectrum changes.

When the spectrum has been severely altered, the incoming audio my change abruptly. Using this feature will help the filter prevent large spikes from occurring. This may be especially noticeable in bass frequencies.

  • Abrupt change protection
    Enables Abrupt Change Protection.

  • Reduce effect
    Controls when the Abrupt Change Protection filter kicks in.

    If Abrupt change protection does too much (signified by white dots at the edge of the display), you can make it worry about fewer overshoots, using this control. Higher values mean less protection.

Bands panel

The Auto EQ number of frequency bands.

  • Bands
    The number of bands to use for the Auto EQ.

Flat frequency response panel

This slider helps to keep the frequency response of both sweeps and pink noise flat.

Similar to Flat frequency response.

  • Flat frequency response
    The flatness value.

    0 does nothing, 100% moves the measurement strength at crossover frequencies from -6 dB to 0 dB. See the thin lines in the Bands display.

  • Flat band tops
    Changes the shape of multiband processing bands.

    This enables a different band splitting mode with flatter top areas of the different bands, and a different mechanism to keep the frequency response flat.

    The advantage of this is that bands have less impact on each other, which can be used to generate a more stable sound image.

    See also Flat tops.

  • Protect
    -

Median display panel

Median display controls.

The median helps to set up the Auto EQ correctly. Good settings means that the Auto EQ does nothing on average. You should not set up the Auto EQ to compensate consistently present issues in the input signal (except when you do so using Band mix.

It is really important to stress that the Auto EQ should on average (after playing multiple hours of "typical" programming) do nothing. So all the median lines should be very close to 0 dB.

If the Auto EQ is "ab"used to always change the spectral content, it will make wrong assumptions about the audio that can lead to audible effects.

  • Reset median calculation
    Throws away all the historic median data and starts to measure anew.

  • Hide median display
    Removes the median displays.

    Also slightly reduces the CPU load.

Compatibility panel

Options for old presets.

Do not turn this on.

  • Legacy mode
    Needed for old presets.

    Do not turn this on.

  • Heavy CPU (compatibility)
    Needed for old presets.

    Do not turn this on.


Levels section

Controls the Auto EQ target levels works.

Levels panel


  • Frequency
    Center frequency for this band.

  • Relative target
    Target level for the Auto EQ.

    Auto EQ will keep the level in bands right where desired. This slider determines the appropriate level for each band on a +/- 12dB scale. Where the sliders are in that scale is irrelevant. The only thing that matters is the relationship of the bands to one another. For example, in a two band scenario if band 1 is at +2dB and band 2 is at 0dB, thatís identical to band 1 being at 0dB and band 2 being at -2dB.

    Important: The best results are obtained if, on average material, the meters are all in the center. The default settings are generally ok, but for different types of content some adjustments may be needed. To determine whether the levels are in the center on average, look at the median display.

  • Effect strength
    Determines how much effect Auto EQ has on each band.

    This filter does not have to fully correct spectral imbalances. Using this slider will make the filter do less correction. If band 1 is 6dB too quiet, and this is set to 50%, only 3dB of correction will happen.

  • Max cut
    The maximum amount of reduction the filter can make for this band.

    Setting this close to 0 dB makes the filter slightly less effective, but can greatly reduce audible changes in spectrum, especially for the center bands.

  • Max boost
    The maximum amount of increase the filter is allowed to provide for this band.

  • Band mix
    How loud each band is mixed into the end result.

    After correction has been applied, it is possible to still increase or reduce the output of the band.

    If you want to adjust the spectrum here, use Band Mix, not Target level for the Auto EQ.

    Auto EQ will keep the level in bands right where desired. This slider determines the appropriate level for each band on a +/- 12dB scale. Where the sliders are in that scale is irrelevant. The only thing that matters is the relationship of the bands to one another. For example, in a two band scenario if band 1 is at +2dB and band 2 is at 0dB, thatís identical to band 1 being at 0dB and band 2 being at -2dB.

    Important: The best results are obtained if, on average material, the meters are all in the center. The default settings are generally ok, but for different types of content some adjustments may be needed. To determine whether the levels are in the center on average, look at the median display. .


Sound section

Settings that control the sound of Auto EQ.

Sound panel

Settings that control the sound of Auto EQ.

  • Channel linking
    Avoids the correction of the channels to drift too far apart.

    It is possible that the left/right balance could be incorrect even within a single band. Use this control to specify how much the correction should be allowed to vary between the channels.

  • ITU-BS.1770
    Measure levels based on ITU-BS1770.

    This reduces the effect of deep bass, and increases the effect of highs above about 1000 Hz.


Bands section

Frequencies and slope steepness of all the frequency bands.

Bands panel


  • Slope to {}
    Steepness of the left slope of the band.

    Less steepness generally gives a more natural, but sometimes harder to control sound.

  • Flat tops
    The level at which the top of this band must be cut off.

    If no compression/limiting occurs, or if all the bands are compressed/limited by the same amount, the end result is guarranteed to be flat in frequency response.

  • Slope from {}
    Slope of the right side of the band.

    Less steepness in general gives a more natural, but harder to control sound.