3D graphical equalizer cookbook

Cookbook: 3D graphical equalizer

It is easy to be intimidated by the large amount of sliders and buttons in the 3D graphical equalizer, but as in any kind of mixer, the different sets of controls do identical things, they are just working under different conditions.

A common graphical equalizer adjusts the amount of signal in different frequency bands. This filter do the same thing, -but for every band, the volume of the signal in the frequency band decides which of the two filters to use. If the signal is very weak, it will use the lower filter, and if the signal is strong it will use the upper filter.

The principle is simple. But the implications may be hard to understand. What do different settings do? This chapter of the cookbook will try to investigate how the different kind of controls are sounding.

Compressing a frequency band:
Everybody has used a compressor. Right? It makes the volume of a sound be more constant. If the sound is weak at some time, it is amplified a little bit, and when the sound gets louder it is muted.

With the 3D graphical equalizer, you can compress certain frequency bands, concentrating on one band at a time, and leaving the rest of the sound alone.

For a band, this is done by lowering its slider for the upper filter, and rising the corresponding slider for the lower filter.

The impression will be, that the band will be more detailed. Soft parts in the band will be amplified. When looking in some sort of spectrum analyzer, this band will now have less components in this band: we actually suppressed most of the power at that point, the fact that we amplified the weak components will be heard be the ear only!

Expanding a frequency band:
An expander works in the same way as a compressor: weak sounds will be weaker, and loud sounds gets louder.

For a band, this is done by rising its slider for the upper filter, and lowering the corresponding slider for the lower filter.

The impression of this can be quite different. This can act as a noise reduction tool, as well as an expander!

Working as an expander: If you wish to suppress weak bands in a frequency band, you should lower the slider for the lower filter. But that may not be a necessary thing to do. The expansion is more prominent if loud bands gets louder, so the first thing you should do is rising the slider for the upper filter. The effect of this will be that sounds that contain these frequencies will be easier to hear. As a general rule: don't expand too much! The band may very well start to jump up and down in a way that is hard to predict.

Working as a noise reduction: Most often one can consider noise to be much weaker than the rest of the sound (otherwise we are in a bad situation aren't we?). That fact invites us to use only the lower filter. Right? We want to leave loud sounds (music?) alone, and suppress weak sound (the noise). As a general rule here is that noise can be heard best in the region of 2-5 kHz (approximately). That is because the ear is more sensitive to those frequencies than any other. Concentrate on that part!

Finding the right threshold levels for the filters:
The two filters start working when a frequency band has passed a certain threshold. You can set these thresholds. The upper filter can not have a threshold that is lower than the lower filter, because that would make the upper filter the lower one...(and vice versa)

A problem in finding the right thresholds is that all sounds are different. Some sounds may need different thresholds.

As a general rule you can use a upper threshold of -40dB to -20 dB. For the lower threshold, please use -60dB (for noise reduction) to -30 dB. (The upper & lower thresholds can of course not cross each other.)

Recipes:

To make a rock 'n' roll stew, one could try to compress the mid around 1-6kHz. This is the region that the ear is most sensitive to. When a sound gets physically loud, the ear tend to compress & distort it, because there is a limit to what can be entered into your head. That is part of why a compressed sound appears to be "louder" or more "powerful". Applying a compression in the region where the ear is most sensitive, makes it appear to be more "loud" or "powerful". You could say, more "rock and roll". Fact is that most of the overtones in a distorted guitar lies in the region 2-6 kHz, and the ear thinks of a distorted sound as very loud.

Soften: Try to do the opposite of the above. In the range of 2-6 kHz, suppress weaker sounds. This will give a sound a mellow appearance. One actually can hear details better as the background is cleared up. To get back some of the lost mid, you can rise the mid on the upper filter (just a little bit)

Sharpening details: Do as above and clear up the mid-region, by suppressing weak sounds. By this one can hear all instruments better. Then rise the treble and high treble of weak sounds (8-20 kHz) a little bit, as this will amplify weak treble that constitute the sharpness and detail of a sound. Due to the amplification of the treble you will have to mute it a little bit in the loud region.

Rhythm, and dance: Most dance music have rhythm. Yes really. Modern kinds of this music tend to use a lot of drums and bass. Remember that compressed sounds "sound loud" and try to compress the rhythm part of the song. That would be the lower-mid and bass region ( up to 400-500 Hz).

Vocals: uses a lot of mid. Affect the region of 300 -1000 Hz and please try to remember that this band sensitive to being risen too much. Be careful with vocals, it is so very easy to hear that something is wrong.

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