How do you judge an EQ?

[poonna]

People are talking a lot about good/bad EQ plugins, yet I don't seem to get the gist of the discussion. Analog-modeled or linear-phase EQs, coloured or transparent, I think I get the concepts of what these are. The thing is, I don't have any idea how these actually sound, and I don't know how to judge them.

I think it would be great if some kind souls here could provide audio examples of these things, providing a raw clip, several EQ'ed clips using different kinds of EQs, perhaps with description of what to look (or listen) for in each clip, why one is superior to another, etc. With raw clip and description of the setting used, those who are interested could also take it to test with other EQs they have and post their impressions here, thus further expanding the examples.

I don't know if I'm the only who want this kind of education from you guys, but I hope it will prove to be beneficial to all of us audio newbies. Thank you very much.

Poonna

[BertKoor]

EQ's are a can of worms, and you want to open it!? Well, good luck on your journey! But I know you have to start somewhere

Tip: as long as you're not sure what you want/need, don't spend any money on it! There are a LOT of free EQ's you can choose from these days which will do the very same job as EQ's costing an arm and a leg.

Bear in mind that words like "good" and "superior" are ALWAYS opinionated and thus subjective. EQ's are merely different, and so better suited for different tasks and situations.

Remember: deciding what to do with specific material is an art of its own.

Maybe you should read a bit about EQ's in a Wiki of some form, get a grip on the basic concepts.

Oh well... We all know the basic type of EQ found on most stereo's: just a set of Bass & Treble knobs. These are simple low-pass/high-pass filters that raise/lower anything below/above a certain frequency.

Simple bass/treble is not enough for most cases (the real trouble area for mixing is in the mid frequencies!) so the whole freq spectrum can be divided into 7, 10 or 31 sections with their own fader. These are the graphical EQ's, because you can kinda "plot" the chizzling you wanna do on the spectrum.

On a mixer you can't have 31 EQ bands for each channel. As a compromise there are sweepable parametric EQ's with which you can boost or cut one, two, or four (or six!) different frequency areas. Some let you control how narrow or wide the area is. That resembles a notch filter.

Knowing the basics, that's step one. Download some freebies of different (or same) type, and play with them. Play with them for hours and hours, so you know what they are capable of (and what not!) Only by training yourself, really doing it, you can make real judgements on what works in which situation and what doesn't.

Oh, and you need a good listening environment. Preferably not headphones but good monitoring speakers, helps you hearing what's really there...

[bobby yarrow]

Nice. I'll just add, I never know if an EQ is ok, good, or great til I've used it in a few mixes. There's a buch of hardware and software eqs that can do magic for somebody I guess. For me, I never really know til I've used it a bunch.

Same goes for everything -- monitors, mics, preamps, instruments, everything. I guess I can tell pretty quickly if a mic stand or cable is ok, but I don't know how it's going to hold up. So try-before-you-buy doesn't really work for me.

[maxxxter]

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[Sascha Franck]

These are actually hi/lo shelves, not hipass/lopass filters.

Admittedly, I never actually understood the difference of those two. Would you care to explain?

[diverdee]

There was an eq 'shootout' here the other year I believe, using a number of similar settings on different eq's on a few test audio files.
Maybe someone will take it upon themselves to perform a similar test again, I found it interesting, although the differences were mostly quite subtle.

[maxxxter]

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[tony tony chopper]

most EQ types & features:
http://www.rane.com/note122.html

but it's not listing this WYSIWYG type of (offline) equalizer:

[oursvince]

For my part, the eq must be parametric (because you can equalizing exactly what you want, contrary to non parametric), have high pass and low pass filters (very useful in the mix to cut some frequencies, in bass and guitar for example)and make a good sound, if you're looking for a good free one, a0 parametric equalizer is excellent( http://www.kvraudio.com/get/1965.html ); this one ( http://www.kvraudio.com/get/1127.html ) seems great too, but not tried yet

[Barbarossa]

Well, it's not easy to describe how a good EQ sounds like, but i will try to explain it with an example, you can do on your own: choose a real fat sawtooth trancelead, set the usual hipass and then choose a medium Q bell band and try to reduce the "noise" in the 6-10kHz area. If you are sucessful, then the synth will sound a bit muddy, but much more balanced. This is the first check, how well the EQ can handle this task, without destroying the whole sound. Now you need to compensate a bit for the lost noise-treble with a hishelf. Set it to 12-15kHz and listen, if the EQ brings out a silky shimmer or if it just produces quite harsh treble, that never seem perfect. Either they are too much, or they are to less. You'll be never satisfied. With a good EQ fitting to you, you'll become satisfied.

Same procedure for EQ-testing works quite well on 909 open hihats, too. Hipass + loshelving to get rid of the rumble and create the correct size of the hihat's body and then reduce the peaks in the treble with high Q settings until you have a flat frequency response.

A good EQ will allow to quite easily reach perfect results (a good source material is needed ofcourse), while a not so good EQ, will correct one thing and always produce a problem somewhere else.

How this can be technically explained, since filters are not that magic, i have no clue.

[Sascha Franck]

hipass/lopass filter have no ability to boost the frequency range they process (except if the 'q' or resonance setting (e.g. Waves RenEQ) applies a q-boost because of the specific 'q' curve): they simply cut the signal above/below the crossover frequency.

Ok, that's more or less what I thought.
But, wouldn't a high/low pass then not be the same as a shelving EQ, minus the option to boost things?

For my part, the eq must be parametric (because you can equalizing exactly what you want, contrary to non parametric), have high pass and low pass filters (very useful in the mix to cut some frequencies, in bass and guitar for example)and make a good sound, if you're looking for a good free one, a0 parametric equalizer is excellent( http://www.kvraudio.com/get/1965.html ); this one ( http://www.kvraudio.com/get/1127.html ) seems great too, but not tried yet

You also *need* to try NyQuist EQ and posifohpit - both are free and excellent.

[bmanic]

IMHO the most important quality aspect of an equaliser is how it treats transients. If it "smears" the transients in a nasty way or somehow makes the original signal "less defined". I'm not sure what really happens but somehow the difference between Behringer vanilla wannabe EQ and Avalon/High-end stuff is huge when it comes to boosting the lows or highs. The difference is not so much in "harshness" as it is in original signal integrity. Actually, like I said, I have no clue at all what is happening and I will try to do some more ear training to understand this.

Any ideas you coding/math/physics gurus?

I'll post some audio examples soon for you guys.

Cheers!
bManic

[Christian Budde]

IMHO the most important quality aspect of an equaliser is how it treats transients. If it "smears" the transients in a nasty way or somehow makes the original signal "less defined". I'm not sure what really happens but somehow the difference between Behringer vanilla wannabe EQ and Avalon/High-end stuff is huge when it comes to boosting the lows or highs. The difference is not so much in "harshness" as it is in original signal integrity. Actually, like I said, I have no clue at all what is happening and I will try to do some more ear training to understand this.

Any ideas you coding/math/physics gurus?

Hihi, the next Electri-Q version 1.5 (which is going to be released tomorrow) will have a maximum phase mode. With that the transient smearing happens *before* the transient. That's a funny thing. In theory, a narrow peak filter may turn a booom into a whoop.
Additionally it features a special set of "phase reduced" filters. They are minimum phase at DC and (nearly) linear phase at nyquist. At about 1kHz the phase is reduced by 50%.

We're currently working on our homepage, but you can already download the demo here: http://www.aixcoustic.com/index.php/Electri-Q/13/0/

Regards,

Christian

P.S.: Have you seen our skyline filters like this (AIXcoustic logo):

[oursvince]

You also *need* to try NyQuist EQ and posifohpit - both are free and excellent.

I've already tried those one and, indeed, they're good, especially posifohpit, but my preference goes for A0 for the sound you get and the fact you can enter the values manually, what is very rare in free eqs...

[Christian Budde]

[...] and the fact you can enter the values manually, what is very rare in free eqs...

Double click a bobble to enter the value manually in posihfopit.

Regards,

Christian