How does eqing work?

[dave m]

Tell me if I'm wrong here.
Is eq just a volume control? For instance, if I bring my eq down along the entire spectrum then adjust the volume up the same amount would'nt they just cancel each other out and nothing be changed? This is just a theoretical question but the answer will help me understand eq a little better.
thanks,davem

 

[The Green Hornet]

Yo Dave M: [you have the same first name and same last initial of my little brother!]

Small World.

EQ-ing means you're tweaking the highs and lows and mids of your recorded track .

For example, when I do a bass line from a patch on my synthesizer, I don't mess with the EQ dials. However, when I mix the total package down to tape/or CD, I like to raise the low EQ a bit and lower the high EQ a bit and the result for one patch is a very gutsy pffffat bass sound. Of course, it depends on your gear and what tweaks it offers you.

Volume is only volume and as you record you learn to use as much volume as possible without clipping. [too much volume = YUKKO noises, especially when digital.

Hope this helps you out.

Green Hornet

 

[gibs]

This is an oversimplification, but think of eq as being the treble/bass knob on your home stereo/radio....but you can adjust it in a more precise way.....gibs

 

[Shailat]

You would not get a cancelation.

When you Eq you are controling the tone of your sound.
If you change the tone and then lift the volume you will get a louder DIFFERENT sound.

If you kill the lows on a Bass and make it sound wimpy and then you lift the volume all you get is a loud wimpy bass.

How ever - when you change Eq you ARE changing the volume of the sound do some degree.If a guitar hass a lot of energy at the mids, then if you cut mids you will change the level.

check you levels as you try to record a sound and then boost highs and see how the level changes!.

 

[pglewis]

One way to think of it is that you are changing the volume for a *specific* range of frequencies. How to specify the range of frequencies varies among the different species of EQ.

 

[BigKahuna]

I don't know if anyone else has that chart that floated around here a while back ... but that would help explain it. I can't find it ...
I say the easiest way to figure out what EQ does is crank the gain knob up all the way and just twiddle the freqency knob (its the one that says stuff like 100Hz .. 1KhZ, etc) back and forth slowly. Listen to what's happening to the sound. Actually that's a good way to zero in on problem frequencies ... by cranking them so you can hear the bad ones really well ... then cutting the gain by just a few dB.
BTW ... you can pretty much only do this on parametric EQ ... not a shelving EQ.
I don't know if that helps or not ...

 

[X]

For instance, if I bring my eq down along the entire spectrum then adjust the volume up the same amount would'nt they just cancel each other out and nothing be changed?

EQ operates in the frequency domain. So, in theory, a digital EQ is continuously sampling your music and transforming it into the frequency domain where everything is simply a sum of sine waves. A parametric EQ is just a guassian curve centered on the frequency you choose with a width that you choose. By choosing the height of this curve and whether it is positive or negative, you define how much those frequencies along your curve are boosted or cut. You can think of a graphic EQ as just a bunch of individual parametric EQs spread along the frequency spectrum with predefined, nonadjustable frequencies and curve widths - you only get to adjust the amount of boost or cut. In actuality, it's more complicated that what I just said - the digital EQ's don't necessarily perform full fourier transforms back and forth between time and frequency domains, but instead they often use "digital filters" which are beyond my level of knowledge, but achieve essentially the same effect. Analog gear does it with a combination of capacitors,resistors,etc to make high-pass filters, low-pass filters, "tuned circuits", etc. And I'm already a bit over my head here.

But to answer your question, if you slide all the eq faders down but then boost the overall volume, you still have a changed sound since there is always granularity to that graphic eq - it's working at 10-20 discrete frequencies (so it will color the sound), whereas the volume control has a much more smooth and even effect across the frequency spectrum.