How do Digital EQ's differ?

[Ocean Zen]

If 1 piece of audio is boosted at 1KHz by 1 db,
how does that differ from the same piece of audio boosted the same way but with a different EQ plugin?

I understand how analogue equipment differs because they are made of phisically different components. But in the digital software world,

What makes EQ's different from each other?

[Left Headphone]

FIR filters and IIR filters. You can do a yahoo search and find tons of articles on this stuff. Its to complicated for me.

[ohm]

and some EQ's even use the sonic fingerprints (Impulse responses) from real analogue eq's to flavour the sound (companies like voxengo do that for instance). I even heard of a technology called dual stage convolution that should be able to totally duplicate the sound of an analogue eq.

basically what matters is to what extent they manage to boost that 1KHz by 1 db without destroying too much in the process. Cheapo eq's tend to introduce artifacts to the sound.

one way of improving is to oversample (work at 4 or 8 times the samplerate of the source material). I'm not an eq expert though, so I can't provide much more help on this.

[kylen]

Good question! Besides the algorithms what the heck is the difference between my Kjaerhus, Voxengo and Weiss EQs...hehe I don't have a Weiss but I touched one in a mastering studio the other day - closest I'll ever get!

[RAYA]

I guess in hardware the more elaborated the freq amps the quietest sound,same as mic preamps bigger circuits bring refinated sounding and higher prices of course.

In soft is a matter of reproducing the circuit in binnary lingo I guess.

[Evan]

I am personally no EQ freak. Nor my ears nor my studio equipment allow me to judge the delicate subtleties of the various EQ implementations out there. But I've had the same question as you and here's the conclusion I've reached...

Equalization algorithms produce artifacts. They usually affect the phase of the signal one way or another. They may clip if overloaded or emulate various tube/tape saturation effects. The eq curves can have various subtleties depending on the algorithm. EQs may use various forms of extra processing to minimize artifacts, aliasing, various types of unwanted distortions... and/or they may use various algorithms to imprint various types of desired artifacts like the forementioned tube/tape distortion.

Therefore, with the appropriate source material (i.e. recording) and with decent equipment and ear training, you may be able to pick up the differences in EQ implementations and decide what sounds better and what not.

As far as the source material goes (for EQ testing), I think it's better to use recordings of natural instrumens (drums, guitars, bass, voice etc) because the ear can identify artificial processing more easily. Your brain knows how a voice is supposed and not supposed to sound like. If an EQ does unwanted stuff to a vocal sample, it should be easier to pick it out.

I hope I have helped and I hope I am not terribly wrong as well

[citizenchunk]

... Besides the algorithms what the heck is the difference between my Kjaerhus, Voxengo and Weiss EQs...hehe I don't have a Weiss but I touched one in a mastering studio the other day - closest I'll ever get!

the algorithms are the difference. that's DSP. that's all it is: different algorithms. there isn't any witchcraft or wizardry going on here--just math.

that being said, it's a little different when you compare plugin EQ's (Kjaerhus, Voxengo) to an outboard unit (the Weiss EQ-1), because there are many other external factors at play. in order to get to the EQ, you first need to get "inside the box"; in the case of a plugin, your dealing with an audio interface, then the host software, etc., which contribute to the overall sound that you hear. in the case of the Weiss, you feed it an AES/EBU signal, which it needs to lock to, thus introducing the possibility of jitter. so, yes, i suppose there are more issues when you consider the bigger picture.

if you really want to delve into frequency domain DSP, i suggest you arm yourself with a hefty background in Calculus. but if you can see past the integrals and imaginary numbers (they always scare me), you'll find that there are many reasons why 1 digital EQ can sound different from another.

== chunk

ps - i've heard nothing but good things about the EQ-1, and its LP/DYN versions. i can't wait to get my hands on one. i'm already blown away by the DS-1. were you totally blown away by the EQ-1?

[Ocean Zen]

TriTone Digital's Eqs have just blown me away after trying the demos.

They're the fattest smothest sounding EQ I've heard yet

Check out the demo for Hydratone & ValveTone at www.tritonedigital.com

[texture]

A lot of eq's distort the sound, and are not just a simple system. This can really give an eq a lot of character.

Some EQ's seem to fizz at 5KHz much more than others that simply boost the level. I personally think this is pleasing to the ear.

[Ian Stone]

Basically, from what I understand about making EQ's is it all comes down to filtering. Whoever produces the EQ in question may add more high pass filtering than another for example.

[snooky]

TriTone Digital's Eqs have just blown me away after trying the demos.

They're the fattest smothest sounding EQ I've heard yet

Check out the demo for Hydratone & ValveTone at www.tritonedigital.com

btw, will the free plugs be availbale for PC?

[kylen]

the algorithms are the difference. that's DSP. that's all it is: different algorithms. there isn't any witchcraft or wizardry going on here--just math.

that being said, it's a little different when you compare plugin EQ's (Kjaerhus, Voxengo) to an outboard unit (the Weiss EQ-1), because there are many other external factors at play. in order to get to the EQ, you first need to get "inside the box"; in the case of a plugin, your dealing with an audio interface, then the host software, etc., which contribute to the overall sound that you hear. in the case of the Weiss, you feed it an AES/EBU signal, which it needs to lock to, thus introducing the possibility of jitter. so, yes, i suppose there are more issues when you consider the bigger picture.

Hi chunk - yes I was thinking the most important differences might just be the algorithms - not which ram the EQ is sitting in or which cpu processes the algorithms. That's as close as I'm gonna get though I don't have the math to unravel the dsp part, that's your job!

But if it is mostly the algorithms then sooner or later a Weiss quality plugin should appear at KVR - that's what I'm hoping our future is anyway, for EQ and other devices. You guys write them I'll buy them and support you!

BTW - I was on a tour of the studio the other night and didn't get to actually hear the Weiss (that's why I touched it to let it know I'll be back) - maybe next time!

[snooky]

TriTone Digital's Eqs have just blown me away after trying the demos.

They're the fattest smothest sounding EQ I've heard yet

Check out the demo for Hydratone & ValveTone at www.tritonedigital.com

btw, will the free plugs be availbale for PC?

so, no one knows?

[Kraku]

I've noticed that if I use certain EQ's to boost a kick drum somewhere around 55-80Hz, I'll get a muffled and gutless sound which just goes *mmmpphhhhh* and that's it. If, on the other hand, I choose some other EQ's for the job, I'll get a real kicker that kicks the ribs through the lungs. So there are differences.

[lfm]

My guess is that most pure soft EQ plugins have simpler algorithms due to otherwise very cpu consuming plug and almost impossible to do realtime.

Those hardware DSPs type UAD-1 and such with their own processors don't have to make such sacrifices. The plugin communicates with hardware and get the job done.

Same for reverb and just about everything in effects I would say.