Equalize

input file : source soundfile

output file : destination soundfile (when marked)
or result.wav (for unregistered files)

processing mode : local or global

A multiband graphic equalizer is provided allowing you to shape the frequency content of the analyzed signal. The number of bands depends on the sampling frequency and is equal to 8, 9 and 10 for 11.025 kHz, 22.050 kHz and 44.100 kHz sampling, respectively.

Equalization is usually employed to shape the sound of different instruments, e.g., to add a 'fullness' effect to weak instruments such as the acoustical guitar or to increase the 'crispness' in percussion instruments such as the bongo or snare drums.

Gain

Gain is used to change the frequency content of the signal in different frequency bands. There are separate gain sliders for each frequency range and an additional slider for the overall volume regulation. Use the band sliders to determine the shape of the equalization curve and the volume slider for the fine volume adjustment. The number displayed above each slider shows the gain, expressed in decibels : the positive values result in amplification (frequency boost) and the negative values in attenuation (frequency cut) of the corresponding signal components.

NOTICE

When the signal is amplified some of its parts may fall out the available dynamic range. All samples 'sticking out' are clipped which may result in audible sound distortions. For this reason, if the clipping lock placed below the volume slider is triggered (or if the warning about clipping occurs on the screen upon completion of equalization) you should consider processing the signal once more with reduced gains.

Linear phase

If you want the equalizer to preserve the shape of the input signal check the Linear phase box. The linear phase condition (allowing one to eliminate nonlinear phase distortions) is achieved by bi-directional processing. The shape-preserving equalization is strongly recommended when processing is restricted to a local area.

Equalization presets

To save equalization settings as a preset press the Presets button situated at the bottom of the Equalizer dialog. The Equalization presets dialog will appear on the screen allowing you to save the current settings (use the Save button) under the name of your choice. Up to 30 different settings can be saved. The same dialog allows you to load an existing preset by highlighting the appropriate name and pressing the OK button.

For your convenience a set of nine standard (predefined) presets (Flat, Bass cut/boost, Treble cut/boost, Mid cut/boost, Side cut/boost) are provided. Predefined presets (displayed with an 'asterisk' mark next to them) are write protected, i.e. you will not be allowed to save the user-defined presets under the names listed above.

NOTICE

The equalization presets are stored in the configuration file dartwin.eql. All settings will be lost if this file is deleted or corrupted outside of DART XP Pro.

Previewing results of equalization

To perform on-line tuning check the On-line box and select the processing range (entire file, from cursor, local, block). Then press the Play result button. Working in the on-line mode DART XP Pro will allow you to listen to the equalization results while changing the program settings. Each time you modify any of the settings the green Ready light situated next to the On-line box will go off - it will be switched on again as soon as the results obtained under the new settings are available. At any time during the test you can press the Play source button to bypass filtering and listen to the original recording.

If your computer is too slow to perform tuning in the on-line mode leave the On-line box unchecked. In cases like this all experiments will be performed off-line on a selected fragment of the recording.

Local equalization

The equalizer can be operated locally, i.e. in the selected area only, as follows:

1. If the output file does not exist yet or is not opened, a new soundfile, identical with the input file, is created prior to processing.

2. The equalizer is run in the selected area and the corresponding block of samples in the output file is modified.

If the output file already exists and is opened, only the second part of the above procedure is realized.

NOTICE

When the results of local equalization are pasted over into the output file, some discontinuities may appear at the boundaries of the selected block. Most of the time this problem can be avoided provided that the equalizer is operated in the linear phase mode; if not - try using DART XP Pro tools to enforce a smooth transition.