How to use a graphic equalizer (EQ)
By Andrew Kim posted Oct 18th 2011
This blog post will teach you the basic theory behind using an equalizer to tune and improve the sound you get from music, games, and movies on your PC.
First of all, what IS an equalizer?
An equalizer is an electronic circuit that allows you to selectively amplify an audio signal based on various frequency bands. This is typically accomplished using independent volume controls for each frequenmcy band. The simplest equalizer (or EQ, as it is also known) would be a "bass" and "treble" knob on a basic stereo system. Turning up the Bass will make the lower frequencies louder, while turning up the treble will make the higher ones louder.
In high-end audio reproduction, you need a lot more than just two knobs, as demonstrated by the production soundboard below!
A similar function can be accomplished on most personal computers. However, instead of having a row of physical sliders like those on the soundboard, the PC uses software to control this function. As you can see from the screenshot below, many PC equalizers are designed to look a lot like their soundboard counterparts.
This screenshot (above) of the equalizer from Corsair's Vengeance™ 1500 Gaming Headset controller software shows a "Flat EQ" setup, where the amplification level for each frequence is exactly the same. But how do we adjust these settings?
This second equalizer screenshot shows an equalizer with adjusted settings. In this particular case, the lower (bass) frequencies have been boosted, while frequencies in the 8K Hz band have been attenuated. Since all these sliders can be adjusted, it is possible to vary the sound fairly dramatically.
An EQ is very intuitive. Each slider is responsible for a range of frequencies, and as you increase the number of sliders the sound can be more finely tuned. The higher you raise a slider, the more gain you will get. In other words, the volume increases at that frequency. The most common usage of the EQ is for “bass boost”. Many people love the feeling of that rumbling low bass, pounding away while you bob your head to the beat.
But an EQ can be temperamental, and carries some fine print. Moving an EQ band too much and at the wrong places can negatively affect the quality of the sound. All sound output devices have different characteristics, and the more you understand those characteristics, the more fully and effectively you can utilize the EQ to optimize the sound of your headphones or speakers. If you can manage to achieve the sound you want by lowering some sliders rather than raising the other sliders, this is the way you want to go.
Playing around with the EQ is a great way to maximize the enjoyment you get our of your speakers or headphones. Take some time to play around with the equalizer on your PC to obtain the sound that is right for you. Simply raise and lower sliders, remembering a little bit can go a long way! Then, when you like the quality of the sound, simply raise the general volume up to match how loud you would like it to be.
Tristan Young
posted on Oct 18th 2011Not a very good article. Far too basic. Doesn't explain the proper way to set an EQ at all. For those that really want to know.... It's preferable to cut a frequency than to boost one. With good speakers or headphones, you may only need to cut (or boost, if you insist) by a couple of decibels (dB). With crappy speakers and headphones (the ones most people seem intent on buying), you may need more adjustment than normal. Some people boost the low frequency bands in order to enhance the low-end sounds. Sometimes this would be better left to the correct adjustment of the sound card's mixing levels, and careful adjustment of the gain on the subwoofer itself. EQ's are not for enhancing bass or treble, but rather for flattening the sound. You want to custom-tailor things to accommodate the characteristics of the room (frequency enhancement or absorption), the speakers, and the amplifier. The ideal sound system starts with a flat response. This is what producers do so their mixes sound good on the widest possible array of setups. If you enhance the various frequency bands too much using an EQ it will sound good on some source material, but may be over-exaggerated on other stuff. Start by playing a steady sine wave 440Hz (Middle C) through the computer/speakers/headphones. There are lots of test tracks available for free download, or generate one using a synthesizer. Adjust it to a comfortable level. Get used to how that frequency sounds, in terms of amplitude (volume). Next play a sine-wave frequency sweep in a medium-speed loop, and adjust your EQ levels until the response is flat (no frequencies that sound too loud or too quiet in relation to middle C, and adjacent frequencies. The idea here is to make sure all sounds come out reasonably natural. When adjusting the EQ, cut the desired frequency band (reduce it's volume). When you boost (increase volume), you can get over-exaggeration of the band, and some people even blow their speakers (especially the sensitive tweeters). If you find you have to boost low-end frequency bands too much, it's because your subwoofer is turned down too low. Some subwoofers have an independent control. To make matters worse, you may also have to adjust the settings for the soundcard mixer. Clipping is another thing people need to pay attention to, but if you keep your volumes respectable, and not boost your frequencies too much, you will probably avoid this speaker-damaging problem. A limiter or compressor (software or hardware) in the audio path can help prevent clipping. Finally, play a variety of music, and make final tweaks to suit your taste. Remember, protect your hearing, otherwise you will regret it when you're older. And please, invest in good quality speakers or headphones. The sound out of my near-field active studio monitors and sub is way better than anything put out by Creative, Altec Lansing, Logitech or Bose. I invested less than $600. Here's to better sound through education.
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