SuperEQ

Equalization (British: equalisation, EQ for short) is the process of adjusting the balance between frequency components within an electronic signal. The most well known use of equalization is in sound recording and reproduction but there are many other applications in electronics and telecommunications. The circuit or equipment used to achieve equalization is called an equalizer. These devices boost or cut the energy of specific frequency bands. (source: wikipedia: Equalization)

SuperEQ (Shibatch Super Equalizer) is a graphic equalizer, originally created as a plugin for Winamp by Naoki Shibata. SuperEQ uses 16383th order FIR filters using FFT. Its equalization is very precise. Note that unlike traditional equalizers, there is very little roll-off or overlap between the bands.

Syntax and Parameters

SuperEQ (clip, string filename)
SuperEQ (clip, int band1 [, int band2, ..., int band18])

clip

Source clip. Supported audio sample types: 32-bit float. Use ConvertToFloat if necessary.

filename

Set EQ bands from a preset file (see Preset Files below).

band1, ..., band18

Set EQ bands within your script (see Band Gain Arguments below).

The 18 bands cover the following frequency ranges:

Band #	f (low)	f (high)
1	0 Hz	65 Hz
2	65 Hz	93 Hz
3	93 Hz	131 Hz
4	131 Hz	185 Hz
5	185 Hz	262 Hz
6	262 Hz	370 Hz
7	370 Hz	523 Hz
8	523 Hz	740 Hz
9	740 Hz	1047 Hz
10	1047 Hz	1480 Hz
11	1480 Hz	2093 Hz
12	2093 Hz	2960 Hz
13	2960 Hz	4186 Hz
14	4186 Hz	5920 Hz
15	5920 Hz	8372 Hz
16	8372 Hz	11840 Hz
17	11840 Hz	16744 Hz
18	16744 Hz	22000±Hz

Frequency ranges apply to both .feq preset files and the band arguments.

(Adapted from AviSynthPlus/plugins/Shibatch/supereq.h )

Examples

Below are examples and additional information on how to use preset files and the band parameters.

Preset Files

SuperEQ can accept a foobar2k equalizer Preset (.feq) file. Foobar's equalizer can be found in the DSPManager, and presets are adjusted and saved from there as well.

A Preset file is a text file with a positive or negative integer on each line. Nothing else is allowed on the line, except white space. Empty (blank) lines are ignored. Each line sets the gain in decibels for a frequency band. All text after the first 18 non-empty lines is ignored, allowing you to add comments to the file.

Preset files can be found in your \AviSynth+\Examples folder or here, or may be found by searching the Web for "foobar2000 presets."

Example 1: Using a Preset file:

SuperEq("C:\Equalizer Presets\Loudness.feq")

Contents of Loudness.feq:

4
4
4
2
-2
-2
-2
-2
-2
-2
-2
-4
-10
-7
0
3
4
4

*comment*
(text after the first 18 non-empty lines will be ignored)

To give a very rough indication of the frequency response of the above example, here is a screenshot of an Audacity spectrum analysis of processed white noise (which should be approximately flat without equalization, allowing for low-frequency variability).

Band Gain Arguments

Band gain arguments allow all 18 bands to be set within your script, instead of requiring a preset file. The values are specified in decibels (in integer format).

Example 2: Boost midrange (speech) using band arguments:

ConvertAudioToFloat()
SuperEQ(
\   0,  [*     0 -    65  *]
\   0,  [*    65 -    93  *]
\   0,  [*    93 -   131  *]
\   0,  [*   131 -   185  *]
\   0,  [*   185 -   262  *]
\   0,  [*   262 -   370  *]
\   0,  [*   370 -   523  *]
\   5,  [*   523 -   740  *]
\  10,  [*   740 -  1047  *]
\  10,  [*  1047 -  1480  *]
\  10,  [*  1480 -  2093  *]
\   5,  [*  2093 -  2960  *]
\   0,  [*  2960 -  4186  *]
\   0,  [*  4186 -  5920  *]
\   0,  [*  5920 -  8372  *]
\   0,  [*  8372 - 11840  *]
\   0,  [* 11840 - 16744  *]
\   0   [* 16744 - 22000± *]
\ )
Normalize() ## avoid possible overload
ConvertAudioTo16bit()

To give a very rough indication of the frequency response of the above example, here is a screenshot of an Audacity spectrum analysis of processed white noise (which should be approximately flat without equalization, allowing for low-frequency variability).

Changelog

Version	Changes
AviSynth+ <r1555	Convert SuperEQ into a proper plugin (Shibatch.dll). SuperEQ no longer automatically converts input clip to Float. (2013/09/15)
AviSynth 2.6.1	SuperEQ gain arguments can only be int, enforce it.
AviSynth 2.6.0	Added custom band setting to allow all 16 bands to be set from script.
AviSynth 2.5.4	Initial Release

Some parts of SuperEQ are:

Copyright © Naoki Shibata

Other parts are:

Copyright © 2001-2003, Peter Pawlowski All rights reserved.

$Date: 2022/02/12 15:10:22 $