Printer Friendly Forum Posts - parametric equalizers?

my question is very simple and its something ive been thinking about for a long time. what is the point of a parametric eq? isnt it technically a three or four band graphic eq? i honestly cant think of a reason why you would choose a parametric eq over a graphic eq. can someone enlighten me about why parametric eq's are popular. the only benefit i see is the ability to select the center frequency(sometimes) but over all i dont see their use.

this isnt a rant, i really want to know your opinion of parametric eq's.

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graphic has a preset center frequency per slider and a preset Q or bandwidth.. all you can do is add or decrease amplitude for that frequency and other near frequencies as effected by the Q roll off.

on parametric you can choose from a variety of center frequencies for each slider/knob, adjust its Q from a variety of Q factors and of course cut or boost the fequncy as needed.

targeted, fine tuning is what the para has over graphic units.

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yuk
quiet rural missouri, near KC.
If your system moves you physically and not emotionally, you have wasted your money.

i guess what i mean is that you can do the same things with a 7 band graphic as you can do with a 3 band parametric. being able to chose the center frequency is pretty lame compared to a proper graphic eq where you can adjust every frequency versus having to pick one.

the only problem i have with graphic eq's today is that you cant find any with sliders anymore. they all have knobs that dont allow you to visualize the eq curve which IMO makes them much harder to set.

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if you have a driver that has a lil harsh spot that needs toned down you can use a para to grab that frequency in a narrow fashion and tone it down. the same goes for over bearing resonances from a sub box or listening area.

with a gragh you may be no where near the frequency you need it. and the broad bandwidth will poorly affect other nearby frequencies anyway.

i like having a parametric to tweek where a steeply crossed over sub (18 r 24 db) and a smow sloped midbass (12db) driver meet. for this use it can make a huge difference.

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yuk
quiet rural missouri, near KC.
If your system moves you physically and not emotionally, you have wasted your money.

soundnsecurity wrote:

i guess what i mean is that you can do the same things with a 7 band graphic as you can do with a 3 band parametric. being able to chose the center frequency is pretty lame compared to a proper graphic eq where you can adjust every frequency versus having to pick one.

Parametric EQ is far more flexible and effective than any graphic EQ can possibly be because "choosing the center frequency" is exactly what you need to do to tame issues properly. With a graphic, you often get close, but with a parametric you can be exact. So I would not call that "lame." I would call that being professional. :)

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a good example at least in a digital para is the 3 band that is included within several Pioneer head units.

i would take a 3 band para over any 7 band GEQ.

as for knobs vs sliders. sliders are nice to see where you are at by looking but as far an longevity in an auto environment, the knobs are sealed better against dust. knobs also seem to make slimmer pieces.

i like digital versions. if up front.

knobs for a trunk mounted.

on my home audio system i went from a proton preamp with an ADC Soundhaper SS-3 to a Sony 1000ESD with no external EQ. the sony only has a nice 3 band para built in and it has helped me tone down a couple areas and center in and slightly boost the very bottom without effecting the frequencies above 50hz much at all.

these things i couldnt do at all even with the great flexability of the SS-3. its bandwidths were just too wide.

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yuk
quiet rural missouri, near KC.
If your system moves you physically and not emotionally, you have wasted your money.

im not saying that being able to select the center frequency isnt a nice function, in fact its the only thing i respect about a parametric but in my mind its still amounts to a 3 band eq. i like using them together with a bigger graphic eq but as a stand alone unit it doesnt allow you to fully tune a system thats not already nearly perfect.

now,if te center points are fully adjustable then thats a different story but i havent used one that was fully select-able, those must be the really nice ones. ive only used ones that have maybe 3 or 4 preset center points which when you break it down it amounts to a 9 band eq but you can only use any 3 bands. my old clarion had a 3 band parametric and i used it to augment my kenwood 9 band graphic by finding center points in between the bands of the kenwood. this allowed me to fine tune a specific section of my eq, it was pretty nice to have.

i guess maybe i just like all the buttons and knobs on a graphic eq too much

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Don't overlook the Q-factor. All the standard graphic equaliser allows is the boost and cut to a predefined frequency and spread.

The difference is blurred with configurable equalisers. Some can be used anywhere from fixed bandpasses to full parametric.

I went off sliders years ago. Though good for some things, they tend to get noisy, and hard to adjust.
For the visual confirmation, I'd be tempted for rotary post with a LED bargraphs, or these days full graphic displays.

you can control the Q factory a little bit on a graphic if you know how to do it, all you do is boost one frequency and cut the two bands around it by a little by. if you know that each band affects the bands around it then you can compensate for it. there is more to using graphic equalizers than just turning things up and down, its a balancing act.

oldspark, what do you mean by sliders getting noisy? im confused...

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That's not controlling the Q - that's changing adjacent frequencies... What if you want the adjacent channels at a certain level?

Sliders seem more prone to contamination than (sealed) round pots.
Though professional sound mixers use them they are digital and often motor controlled. But they are usually more for amplitude whereas rounds are used for tuning (ie, graphic equalisers). Maybe I should ask my mixer mates what they prefer, though I know they have a need to "immediately see" what the amplitude levels are when problems arise.

AFAIK, typical slider graphics still use analog pots, though being vertical they are less prone to dust etc ingress.

Here's the difference in my opinion: a parametric EQ is a tool that is used to correct issues with frequency response. A graphic EQ is a tone-control used by people who like to tweak their system to suit their mood.

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well i didnt think people felt so strongly about parametric eq's.

as far as my statement about Q control on a graphic eq, its not exactly a Q control obviously because you cant control the exact width of boost/cut, my point was mainly that there is more to using a graphic eq than just turning knobs to make the system sound how you want it. i use them just like you say, to fix response peaks and valleys. if you still end up with a flat response then why would it matter whether or not you can adjust the Q.

is there something that i just dont know about how a parametric eq functions? to me it is just the same a graphic eq just that the controls are implemented a different way.

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The point is this: A graphic EQ is fine, it is just limited in that the user is stuck with whatever parameters of Q and center band frequency the designer used. A parametric is simply much more flexible, and in the hands of a pro using the correct testing tools, much more usable to actually correct system issues. Rather than hoping the GEQ happens to be designed just right, they can use a PEQ with confidence that they can adjust it be just right. A GEQ is a much more hit or miss solution. It's like using a shotgun. A PEQ is much =more precise. It's like using a rifle.

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we can explain it to you 50 ways to sunday, but we cant understand it for you.

you can make a para do things that a GEQ can do, but a GEQ cant do the things a para can do.

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yuk
quiet rural missouri, near KC.
If your system moves you physically and not emotionally, you have wasted your money.

itsyuk wrote:

we can explain it to you 50 ways to sunday, but we cant understand it for you.

you can make a para do things that a GEQ can do, but a GEQ cant do the things a para can do.

i understand it all perfectly. what i dont understand and probably never will is why everyone seems to like a parametric so much. i understand that it is much more precise and can be just as effective, but what if you have multiple peaks? or a peak and a valley within the same parametric bandwidth? you cant adjust a PEQ up and down within the same band. a sniper rifle is nice if you only have a few enemies but sometimes you need a machine gun. plus, most PEQ's are still limited to set bands that you get to choose one of within a bandwidth, if you have a PEQ that is fully selectable then that is great but that still goes back to the point about if you have multiple response issues to deal with within a single band.

sorry if i sound hard headed, my intention is not to be aggravating either, i just find it strange that no-one except Dyohn seems willing to meet me in the middle.

either way, its all good, honestly i think someone should produce a combo EQ. ive had awesome results when i could use both at the same time, maybe ill buy a PEQ to augment my 12 band and see how that works out. ill just have to make sure it can be set in between the set bands on my GEQ or else it will be useless.

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Tackling it one way, if you have 3 peaks, or 2 peaks and 1 trough etc, then that's one typical 3-channel parametric.
If it were possible to use a graphic as you described, that's 9 channels used.

Another way - a parametic is used to fix certain select problems. Its output is usually put through a full-band graphic to provide the overall frequency balance.

Many systems have mains notch filters (50/60Hz etc) or 19k filters etc etc before or irrespective of later graphics. Parametric eqs are a similar tool but tunable for whatever problem be it resonance, snare rattles, bad kick drum mics, etc.

I see parametrics and graphics as having different functions. A graphic is very limited for use as a parametric, and a parametic is often wasted as a graphic else is limited by the number of bands. Then again, a (say) 3 channel parametric can often provide the "typical" curve that 8-12 channel graphics can provide.

But if using DSPs and digital equalisers, I see no reason that the lot can be covered, eg - adding multiple parametric filters and cascading into a graphic. It's merely limited by what the interface software can provide.

so i guess oldspark just hit the nail on the head, they seem to be two parts of the whole equalizer. they have their own functions, though similar in nature, usually you can get by with using one or the other. but, for a total suit of tools to tune a system i really think you need both working together to be able to handle whatever your system throws at you.

still, if i had to choose one, id still pick a 7 or higher band GEQ. if i couldnt get more than 7 bands then id choose a Parametric. the ideal situation would be to have your 3 channel crossover first, then your graphic eq to level out the response, then a parametric to fine tune anything that the graphic eq cant touch because of the set center points.

i didnt want to say it at first but what made me think of this thread was thinking about how most cheap-mid level head units come with a parametric built in and only when you get into the more high end head units do they give you a nice graphic eq( i know this is a huge blanket statement). this general order would suggest that one type of eq is better than the other. with that being said, it confused me as to why there are so many options for aftermarket parametric eq's and not much to offer in the way of a nice graphic eq, they are either really small or really big, whereas a parametric seems to come bundled with just about everything.

i asked because i wanted some opinions as to why a seemingly worse choice for total system tuning would be so much more popular than a decent sized graphic eq.

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Because it's a better choice, not a worse one. I give up.

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I don't know of any parametrics on cheap or mid level units.
And I would have thought parametric first followed by a graphic.

But they are different.

How would you remove 120Hz hum from the 120Hz graphic band that you want to boost?

DYohn] wrote:

Because it's a better choice, not a worse one. I give up.

sorry, i said that wrong i guess. the "seemingly" was meant to imply the hierarchy of Eq's based on what i wrote above that about high end HU's having graphic eq and middle end HU's having parametrics.

like i said, i know that was a blanket statement and its not true in all cases but ill give you my evidence.

my example will be JVC, their top level radios that are equipped with time alignment and a full feature 3 way crossover also have a large GEQ. the lower model JVC units have a selectible parametric.

other evidence, the pioneer stage 5 radio has a built-in 30 band.

i cant speak for all brands though i know that the top level clarion is equipped with a parametric, but i think its a 5-band.

i didnt mean to say that one was worse than the other in terms of usefulness but the way that manufactures offer these features in relation to price would imply that one is more desirable to have than the other.

trust me, i am on board with using parametric equalizers and you guys have done a good job helping me understand their usefulness. ill probably get one in the future.

oldspark, i dont understand your comment about 120Hz hum. what hum are you talking about?

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If your noise is on a band where you need a boost, then you have to remove the noise, before fixing the dip... ANY equalization on the frequency will only enhance the noise, if that's where the noise is. That's what the EQ does, and it can't differentiate between desired and undesired frequencies. 120Hz would most likely be a ground loop, fairly easily removed, isn't it?

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Yes, any hum in an audible frequency means you are what we call here in America "SOL," or "s*h*t out of luck." Fix your hum issue first before you do anything else.

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A bit hard when it's "fixed" on the source - ie, disc or program.
But hence parametrics etc.

well that is a given that an eq will boost noise as well as the normal audio. i never mentioned having any hum in my system so it confused me as to why it was brought up at all. you would need to deal with the hum a different way

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Yes, but you were asking why parametrics? The hum or any noise is just an example (like FM whistle etc). And sure, hum or whistle or snare rattles should be avoided when recording, but what if not?

But hence parametrics for "source" engineers.
If you mean general domestic etc use, then graphics are the norm.
I don't see why anyone would consider a parametric in those situations.
Of course, if they have a particular note which to the listener is over emphasised and its elimination by graphic spoils the overall balance, we repeat the forgone discussion...

yea i dont know anything about the recording world uses of parametric equalizers, my post was meant to be specific to car audio, maybe even home or pro audio but not recording.

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It's still the same in principle. If you have specific frequencies that you need to address, then use a parametric. Recording engineers require that to get the output suitable for consumers. By that I mean getting rid of undesirable noises, resonance, etc.
Of course the engineer's or recorder's taste wrt to the overall equalisation curve may not be the end listener's choice or what the sound environment reproduces - hence the addition of graphic equalisers - but rarely do they include some exceptional narrow-band aberration.

Again, parametrics are used when needed. It may be to get rid of any hum or noise - however generated - or maybe by very fussy listeners with specific desires.

BTW - the 120Hz hum was merely an example of 60Hz AC noise etc. But it could be anything - maybe interference from electric drills etc, though in certain cases digital techniques may be required. (A parametric may do motor noise because although the "pulse rate" may vary, the interference frequency is usually constant. But if they exhibit a varying pitched whistes - like alternators...)
Certainly try to remove all those sources - eg, mains filters for domestic equipment, caps or shielding for domestic or mobile. But until that is eliminated, post filtering is the only option.

Digital filtering and software smarts has changed that world considerably. I recall early scratch filters being high-Q fixed or parametrics. These days scratches are recognised by their digital signature and subtracted. Again - old vinyl scratches being a mere example (CD scratches have a plethora of techniques or should I say, algorithms?).

Though I have had HUs with 3 or 5 band EQs, none of those were parametric.
These days I find my Alpines with their configurable roll off frequencies generally adequate, though with modern DIY mixed recordings I'd like a nice graphic EQ with mechanical sliders for inter-song adjustments. (No - I don't pre-process individual source or track EQs before I transfer to CD or USB etc. Maybe if I find some free automated software...)

i would assume they have all kinds of nifty digital filtering devices to get rid of unwanted noises during the recording process. the stuff we use in car audio is like a baby's rattle compared to the cutting edge equipment in use today by recording studios.

also, its easy to make a case for using a PEQ to filter a hum of a certain frequency but it still wouldnt be perfect if you also had audio mixed in at the same frequencies. unless you had a super fine Q control to be able to filter your 120Hz hum for example without touching other frequencies around it then i guess the loss of that one frequency wouldnt be noticed by a listener

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