Sweeping Frequencies?? Parametric EQ

[Shack]

Hello, I read a lot of articles on parametric eq's where people say use the Q to sweep the frequencies to find where the frequency for a particle sound is. How does one do this please?

[Jeff_D]

the "q" if im not mistaken is the range of freaqueny affected by the boost or cut of the eq- a small q affects a wider area than a large q ( that might be backwards- i forget)

[PROTOOLSJUNKIE]

RIGHT, THE Q OR OTHERWISE KNOWN AS BANDWIDTH ARE THE RANGE OF FREQUENCIES BEING EFFECTED. YOU CAN HAVE A NARROW OR WIDE Q. SOME SOFTWARE REPRSENT THIS IN NUMBERS AND IVE SEEN THEM BE ASS BACKWARDS. SO BASICLY THERE IS NO STANDARD YET. BUT YOU CAN HEAR THE DIFFERENCE.

WHAT PEOPLE REFER TO GENERALLY WHEN THEY SAY THAT, IS SET THE Q ABOUT MIDWAY TO NARROW, TO START. THEN BOOST THE GAIN AT LEAST 3DB, AND SWEEP WITH THE FREQ POT TO FIND THE FREQUENCY YOU WANT TO EFFECT, YOU MAY EVEN WANT TO FIND THE MOST ANNOYING FREQ YOU CAN, NARROW THE Q, AND PULL IT OUT OF THERE ALL TOGETHER.

[Shack]

Thanks, I understand about the Q, but what confuses me is the actual act of 'sweeping'. Is it physically turning the frequency knob up and down and if so, what should I actually be listening for?

People keep turning about the problem frquency, etc, but all I find when I narrow the Q and tweak the Frequency all over the place is that the sound just keeps changing.

Basically i'm confused about how to 'sweep' and what to be listening for?

[PROTOOLSJUNKIE]

yes, sweeping is turning the freq. knob.
and you listen for what you think sounds good. and that is the hard part. basic things to think about is that you want your mix to fill a frequency spectrum as smoothly as possable, so the freq that dont sound so good in a kick drum like 300-450hz for instance can be pulled out of the mix meanwhile adding that freq to the snare for more body giving both sounds room to breath, and sound good. not that a snare and a kick drum are ever the problem tracks. not so much as the kick drum and the bass.

there are no boundries, just experiment. have fun NOTHING IS BETTER THAN EXPERIANCE.

[Shack]

Aah, it's all very clear now. Basically I turn till I sort the problem out either by boosting or cutting. Thanks.

[littledog]

Actually, PTJ, there is a standard for Q - higher numbers mean narrower frequency range, but maybe some manufacturers are ignoring the standard. On a mixing desk the Q pot will do the same thing - turned to the right narrows the band, to the left widens it. Anyway, nice to have another ProTools user on board (sometimes i get lonely!). Usually the only time it gets mentioned on most bulletin boards is when people are complaining how crappy they think it sounds. What type of PT system do you have?

Shack, one very common technique for corrective EQ is to sweep boosted frequencies with a narrow Q to find where something sounds the worst and then cut at that point and readjust Q to taste.

[teainthesahara]

Originally posted by littledog
Shack, one very common technique for corrective EQ is to sweep boosted frequencies with a narrow Q to find where something sounds the worst and then cut at that point and readjust Q to taste.

Littledog,
when/how often do you find that you perform that technique? What results do you hear overall via that technique ? I regularly sweep using cut frequencies....this is the first time im hearing about this using boosted frequencies....and im finding it interesting. I take it that the frequencies that you eventually cut by this method are harder to pinpoint as being 'problem' area's in the first place, so this identifies them easier? How much do you boost with this technique (i guess anything boosted to high will sound bad) ? What's intriguing me is that one might not have really identified these frequencies as 'problematic' in the first place, so im wondering what the actual effect on a mix will be afterwards. Is the effect kind of like rolling off, to avoid the build-up of less noticible frequencies that cause cummulative problems?

Thanks,
T

[dobro]

Okay, I'll chime in while we're waiting for Littledog. When I do this boost-a-narrow-Q-and-sweep thing, I usually boost to about 10 dB with a Q of about 12. Then I sweep. If a frequency is really problematic, it'll just jump out at you with an ugly sound. But when I learned how to do this, I got overenthusiastic about it, and started sweeping *all* my tracks and cutting every frequency that sounded less than sweet. See, when you start doing this sweeping thing, you'll find frequencies that sound kinda unusual, although they're not really ugly. Anyway, one day I compared a mix where I'd been sweeping enthusiastically to one where I hadn't swept at all. Guess what... the unswept mix had way more life in it - I'd been sweeping the life out of the other mix.

Anyway, I've got a theory about sweeping for bad frequencies. It's a useful tool, but it only applies if you've miked something poorly. If you mic it right, there's no need for that surgical EQ work.

[mixsit]

Since wer're kicking this around..
When listening to the mix, you'll notice areas on a track that seem out of balance or just inappropriate. Fix that part of the sound in your head, then sweep to make note of the frequencey nearest the center of the problem area, then go back to flat- give your ears time to get back to what 'normal' was. Then start pulling it out. After a while you'll be getting pretty close right off.

Never tried cutting at one place and then looking for somewhere else to boost that back in. More of a circular process of cutting what's in the way and knudging up where needed.
"Whatever gets you through the night..."
Wayne

[littledog]

dobro is absolutely right. If you boost high enough, almost any frequency will sound kind of ugly. So a good rule of thumb is, (as mixsit suggested, and this can apply to any EQ technique) after you are done EQ'ing, bypass it, and see if the EQ'd sound is actually any better than the original. (Do this listening to the whole mix, NOT soloed!)When in doubt, leave it out. Never automatically apply EQ (or anything else) to tracks that already sound just fine.

Here's a common example of where the technique is useful:

You record a female vocalist who has a problem frequency area in the upper mid-range of her voice (assume this is a natural artifact, not something induced by your poor engineering technique) - kind of a bit of harsh metallic timbre that you would like to smooth out a bit. Using the boosting narrow Q technique, you find the frequency that makes that particular timbre the most excruciating, and now you know where to cut.

[Shack]

Just to check with you all, you do this narrow q/boost/sweep thing on a particular track/channel with the rest of the mix playing right? i.e. you dont solo it and do it, am I assuming correctly?

[dobro]

No - you solo the track and sweep it - it's just that one track you're listening to. Then before you commit to any changes you've made after the sweep, bung it back into the mix like Littledog says and listen to it. Better? Okay, keep the changes. No improvement, really? Then don't keep the changes.

[Shack]

Sorry to keep going on Dobro, but I find that say I solo just the bass drum and do the narrow q/boost/sweep thing, the sound just changes as I turn, I don't find a 'dramatic' point whilst sweeping, or am I doing it wrong?

[mixsit]

Shack, with a drum for example, if the goal was reducing say, the primary resonance of the drum because that part was too forward, then as you sweep, it would tend to be a frequency that would jump out the most. Perhaps a moderately narrow Q (1- 1/2 oct.?)would work better, not beign so radical.
Often the part you may want to pull out isn't necessarilly the loudest on the track, like the 300-500 cardboard sound in a kick we often cut, insn't as loud as the hump that might be down around 100, so the sweep is only good for finding the freq. but it won't actually jump out.
Yea?
Wayne

[dobro]

"Sorry to keep going on Dobro, but I find that say I solo just the bass drum and do the narrow q/boost/sweep thing, the sound just changes as I turn, I don't find a 'dramatic' point whilst sweeping, or am I doing it wrong?"

Well, my first guess would be that the drum track's okay, and that's why you're not hearing anything wrong with it. But Mixsit's idea is a good one too - you could use a broader Q - try 6 or 8 for example - and sweep again. Plus, Mixsit's using his experience of where typical problem frequencies for particular instruments are typically found. Try that range he mentioned and listen again with a broader Q, but again, I figure the sound on that track's probably okay.

Do you have an acoustic guitar that you've recorded? That might be a better thing to try out sweeping with to find out how it works. AG's got frequencies going on all over the place, and if you mic it badly, there'll be ugly frequencies in there. If you try that, look at the 300-400 Hz range in particular.

[crimp]

Here's a good article on those problem frequencies you guys were talking about.

http://www.dbmasters.net/hrc/news.ph...ew_story&id=38

crimp