How to use Parametric EQ

[Dunno]

Credit for this goes to flattop100 at Riovolution, I just edited a bit to suit mistic

Bootnote: Sound is the most subjective thing on the planet/everyone's a sound guy--so in the end, do what sounds best to YOU. This tutorial is to give a basic understanding of how the EQ works, and to give you a starting point in making your own presets.

Now, I'm going to assume that you're EQing to make good stuff sound BETTER. I'm making my suggestions without any regard to battery life.

For starters, think of the default EQ--Bass and Treble. Since there's two "thingies" to adjust, we could call that a 2-band equalizer. Moving right along, we can call the "Advanced" setting 5-band: Low Bass, High Bass, Mids, Low Treble, and High Treble.

If you will.

I'm going to start getting technical now. I apologize in advance, but there's no help for it.

Back to high school science class...remember the part on sound and physics, which was taught at the end of the school year, and you spent most of class staring out the window at the women's track team?

Good times.

Since sound occurs frequently, the sound waves are often referred to in blue-collar circles as frequencies. However, scientists are white-collar, and like official sounding terms. Dr. Owit Hertz died for science, so his last name describes the number of sound pressure waves per second. The hertz was born anew! (I can see the movie now: The Passion of Hertz...)

Now, since we humans are nothing more than singing bags of meat, we're falliable. We can only hear between 20 and 20,000 hertz. (That's 20 sound pressure waves per second to 20,000 waves per second.) --That's average. Your actual mileage may vary.

OK, so I can't see the point of all this yet, but I can smell it.

With the 5-band EQ, you can choose what section of the audio range you're boosting or cutting; namely, the frequencies.

Some examples regarding frequencies:

A)A piano emits sounds from about 28 hertz up to 4200 hertz (4.2 kilohertz). (That's the fundemental, anyway; sound does this weird thing where it creates "overtones." Basically, if you have a low pitch and a middle pitch, the sound will add up (yes, like 2nd grade addition) to a high pitch.)
B)Most telephones reproduce 300 hertz to 3.5 kilohertz.
C)Your average home theater subwoofer reproduces sound from about 120 hertz down to about 40 or 50.
D) The typical human 'hiss' or 'S' sound runs the gamut from about 8 khz through 16 khz.

Now, it would be nearly pointless to boost or cut only one hertz--you would hardly notice it. So EQs adjust all the frequencies around a central point. This is part of the reason we refer to them as bands.

This is where parametric EQ kicks in, and also where the "Width", 'Q' setting on your EQ becomes important.

I need to introduce another scary music term, the "octave." In music, it refers to equal pitch intervals, one above the other. (Remember Dorothy in The Wizard of Oz? Sing the first word of Somewhere Over the Rainbow...you've sung an octave!) In sound (as opposed to music), we use the term 'octave' a little differently. Our ears work logarithmically, so that an octave is a frequency ratio of 2:1. Translation: There is one octave between 100 and 200 hertz, and one octave between 1000 and 2000 hertz.
In EQ circuits Q is defined as the center frequency divided by the half power bandwidth. On a 1/3 octave graphic equalizer, for example, the half power point at 1 kHz is 232 Hz wide. The Q is thus 1000/232 or 4.31.

The 'Q' on the iriver adjusts how wide an octave the EQ adjusts, in other words, how many frequencies are included in the boost or cut. On the iriver, you can go from 0.5 of an octave, to 6.4 octaves.

The best example I can think of is a dam breaking. A narrow octave width would sound like the first teeny tiny jet of water, hissing so softly you can hardly hear it. A wide octave width (really frikkin' wide), however, would sound like the whole wall caved in, a full "static on TV" type of sound.

Ouch. My head hurts. I hope this makes sense to some of you out there.

Maybe it would just be simpler if I gave out my EQ settings (using the default Senn earbuds). This won't sound as good to you as it does to me, since we probably wear our earbuds differently, and since we hear differently. On the other hand, I do get paid to make bad bands sound better, so take this as gospel.

Freq: 12k
Gain: +3db
Q: 1.2

Freq: 2k
Gain: +1db
Q: 1.2

Freq: 400
Gain: -2db
Q: 1.2

Freq: 120
Gain: +8
Q: 0.8

Freq: 60
Gain: +8
Q: 1.0

I see that some "why do you EQ there?" might be helpful. These are kind of a 'default' I use on most headphones. Normally I use Shure e3's'--here are my settings for those.
12k helps "brighten" the sound. Cymbal crashes et al come through a little more.
2k adds a touch of presence as well--makes thing a little more undertandable.
400 is kind of a messy area, so I turn it down
120 is near the high dry bass sound, and I like bass. So I turn it up.
60 is the part of the kick drum sound that moves air.

EDIT: DANGER, WILL ROBINSON!

As phrenzy says here, boosting the EQ too much can cause clipping, (cutting the tops and bottoms off of the waveforms), which results in damage to either A ) The iriver's headphone amp, B ) your headphones, or C ) whatever equipment you have plugged in downstream of the Karma. So go ahead and tweak all you want, but if you hear distortion, there's probably something wrong.

[vince]

Here's the original thread, and here is phrenzy's post about clipping as referenced above. JohnM's KarmaEQ is useful for visualizing the eq (for instance so you can find equivalent settings by boosting instead of cutting). Note the difference between Q and width, they are same effect with different numbers.