EQ Shaping and control

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BeagleFaceHenry

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Years ago I was 'helping' a pro audio team set up for a festival. They were using a huge, bazillion band crossover and rolling individual frequencies out to reduce/eliminate feedback etc as part of the normal set up....long before the performer came out to sound check.
At the time I was very impressed as the engineer seemed to know all the 'trouble' frequencies and would call out to have them rolled off one by one. I was thinking about this the other day....
I looked around for a plugin (ya, ya...plugin.) but they didn't pop out at me. I did find a 16 channel that I toyed with for a few minutes. I have a guitar track that picked up some feedback, but I wasn't able to zero in on the sound with the crossover with more precision than the parametric.
Moreover, when I hear people talking about EQing and shaping, they're always talking about parametric EQs not multi-band crossovers. Can someone break it down for me? Is the Multi-band better, but more expensive and harder to use, or has it evolved out of common usage? Is a multi-band crossover more effective during a live performance with a lot of resonance and harmonics, and less effective when mixing a recording?
Thanks in advance for the insight!
-jaimie
 
Hey Henry,
First up, and forgive me if I'm patronising you, but a crossover is a device that splits a signal at a certain frequency.
Think of a speaker with a tweeter and a woofer. You'd have a crossover to send highs here and lows there.

There are some very talented and experienced live sound guys here who will confirm or correct what I say, but I think you're more likely to need very focussed eq in a live setting because you may have to deal with the nuances of the environment you're in.
It may be necessary to make very narrow, precise, cuts because of feedback or whatever whereas the studio is, or should be, a controlled environment.
The fine tuning is done with room treatment, etc.
Studio eq is generally more of a broad-strokes affair and when it's not, a narrow Q parametric is usually adequate.

That's my take on it anyway.
Hope that's useful.
 
BeagleFaceHenry said:
Years ago I was 'helping' a pro audio team set up for a festival. They were using a huge, bazillion band crossover and rolling individual frequencies out to reduce/eliminate feedback etc as part of the normal set up....long before the performer came out to sound check.
Click to expand...

That would be a 1/3 octave graphic equalizer, which are still common in live sound. Each slider controls a filter at a fixed frequency, with a fixed bandwidth. There weren't a lot of parametric eqs in live sound because for most users they take more time to dial in, and until recent years they were more expensive.

BeagleFaceHenry said:
At the time I was very impressed as the engineer seemed to know all the 'trouble' frequencies and would call out to have them rolled off one by one. I was thinking about this the other day....
I looked around for a plugin (ya, ya...plugin.) but they didn't pop out at me. I did find a 16 channel that I toyed with for a few minutes. I have a guitar track that picked up some feedback, but I wasn't able to zero in on the sound with the crossover with more precision than the parametric.
Moreover, when I hear people talking about EQing and shaping, they're always talking about parametric EQs not multi-band crossovers. Can someone break it down for me? Is the Multi-band better, but more expensive and harder to use, or has it evolved out of common usage? Is a multi-band crossover more effective during a live performance with a lot of resonance and harmonics, and less effective when mixing a recording?
Thanks in advance for the insight!
-jaimie
Click to expand...

Graphic eq is useful when you need to deal with problems fast at a show. The frequencies are laid out like a keyboard, low to high, three to an octave. But a 1/3 octave graphic is somewhat of a blunt instrument. The filters are fixed and generally not that narrow so you can end up affecting a lot more than the target frequency. Parametric eqs are becoming more common in live sound, but graphics are often still used at the mix position for convenience, because of tradition and to accommodate guest engineers who may want some manual control over system response.
 
Yep. What you saw was the dude "tuning" and/or "ringing out" the system - using a (probably 31 band) graphic equalizer to try to adjust for deficiencies in the system and the room it's in. It isn't really anything to do with shaping the sound of individual instruments, just trying to get the flattest* response possible so that you can make better decisions and maybe not have to work as hard when the instruments come in. It also has a bit to do with adjusting for the resonances in the room to counteract feedback.

In point of fact this is poor practice, and really only sort of works. The best way to fix those issues is proper acoustic treatment in the room and a properly speced and placed speaker system. That's damn hard to do in a lot of venues even when they have a dedicated system installed. The guys who drag their PAs around chasing paychecks really have no option but to take the room as it comes and do the best the can with electronic band aids.

Even in a home studio we have a lot more oppurtunity to "tune the system" via placement and acoustic treatment - the right way.

*...or most flattering or, one might say "the desired response". Nowadays it seems more often than not it means hyped, woofy bass and nasty, crispy highs. ;)
 
Analogue 31 band graphic EQs are slowly becoming a thing of the past, though. I don't think I've seen one in use for years now at a proper top level gig. Most of the time the bigger shows and festivals use some sort of L-Acoustics, d&b, Coda, JBL, Meyer, Nexo, etc line array that is driven by proprietary amps with on-board DSP that handles crossovers, EQ, dynamics, and system monitoring. Programs like SOUNDVISION (L-Acoustics), ArrayCalc (d&b), etc help sort out coverage and splay angles. SMAART time aligns the system. Nowadays graphic EQs are also built into digital consoles and show up on the faders like in the case of a Vi6 or a DiGiCo but I rarely see system designers reaching for them because, 1. the PA usually sounds great on it's own, and 2. when set up correctly there's really no need for feedback elimination or tone shaping. PAs are designed to sound good from the get go these days, it seems. System designers and their crews are focusing more on setting up the PA correctly in the right place than reaching for band aids any more. Science is taking over where chance left off.

Another step forward is the emergence of systems like Martin Audio's MLA and EAW's ANYA. The MLA uses FIR filters and discrete DSP feeds to up to 148 drivers in an array to basically produce any 3D wave front that can be programmed (quite easily, actually) to actually "hard avoid" areas in the room, eliminate sidewall reflections and provide consistent SPL from front to back of the venue. ANYA has 22 drivers in one cabinet that are all discretely controlled via their own amplifier and DSP channel. Phase, EQ and amplitude can then be adjusted on a per-driver basis to sculpt the wave front without ever touching a box or changing it's orientation. Truly remarkable.

So yeah. The last time I saw an analogue 31-band graphic EQ was over Easter weekend when I did a gig in backwards-ass Zambia. They are SERIOUSLY behind the times there. Before that it must have been at least four years ago.

Cheers :)
 
I have a 30 band graphic in my mix rack on my little old analog system but sometimes I leave it flat. At most I'll do minor adjustments for a given room.

I don't even have graphics on my monitors anymore, just digital parametric, but those are mostly set and forget. I've mostly subdued feedback problems using a reference mic to determine specific eq per stage monitor type. Monitors feed back where their response peaks coincide with the response peaks of the mic, among other contributing factors, so flatter response tends to minimize feedback.
 
Groovy, thanks everyone. Sounds like my suspicions were true.
How about mastering? Does a big, graphic come in more handy there or still just as antiquated.
 
BeagleFaceHenry said:
Groovy, thanks everyone. Sounds like my suspicions were true.
How about mastering? Does a big, graphic come in more handy there or still just as antiquated.
Click to expand...
Generally not, and for a couple reasons. Mostly because you shouldn't really be doing that kind of "spot" EQing in the mixing stage, and I think we far more often are going for broader strokes for which the 1/3 octave EQs are not really suited, but OTOH if you do need to get in for surgical work to fix some deficiency that should actually be fixed in the mix the 1/3 octave bands might not be quite narrow enough and/or their fixed centers might not be in quite the right place.
 
I'm just learning all this stuff, but I'll throw in 2 pennies.
My current project is fairly simple. Generated drums. DI piano from a Yamaha. Miked/DI'd bass.
In the past, I've thrown my bass into the mix and then tweaked and adjusted for days. Had a difficult time with too much mid-range, mud everywhere etc. (Steen has heard one of my old tracks).
From what I've learned on this board. I get the cleanest, best sounding track I can WHEN I TRACK. Then I LEAVE IT ALONE! I've learned the hard way that taking a few minutes getting a good sound at the beginning saves you hours and hours in the end. The trick is learning to get the sound right. It's not so easy to "hear" what it will sound like after you add the rest of the tracks and get the mastering suite kicked in...
 
Sure, getting it "right" at tracking is great, but sometimes "right" is not defined until more tracks are down. How tracks work together is more important than how they sound individually.
 
Steenamaroo said:
I absolutely +1 this, but I still find myself trying to resurrect bad recordings sometimes. :facepalm:
Click to expand...

I'm currently trying to fix the bad recording you heard. I can't play the guitar part again, because I was using someone else's kit and don't have it available. I'll never get that SG/Carvin tone with my Hamer Californian and amp sims. Just not going to happen, so I'm trying to clean up what I've got, re do the vocals, humanize the drums, fix the horns (toughest part)...In the long run, I'd probably be better off to scrap and start over, but I'm just that stubborn! :rolleyes:
 
bouldersoundguy said:
Sure, getting it "right" at tracking is great, but sometimes "right" is not defined until more tracks are down. How tracks work together is more important than how they sound individually.
Click to expand...

Sure, that's what I meant when I said, it's not easy to "hear" what it will sound like...
Sometimes you get to ride an eq knob to get the sound right, sometimes you have to do a lot of automation...that's a lot of the fun! But spending hours and hours tweaking gets frustrating and gets you tired of the song. Sometimes it's best to re-do a track once you have that vision, than to fiddle endlessly.
 
I like to think the goal of recording engineers should be to get a sound which doesn't need mixing.
 
japancakes said:
I like to think the goal of recording engineers should be to get a sound which doesn't need mixing.
Click to expand...

Everything needs mixing. The goal is to get the sound at the mic so that exaggerated tweaking is not needed. And some genres require treaking to get a particular sound, but not because of crappy sound to begin with.

Just blabbering...

:D
 
I'm loving the (assumed) unintentional use by ashcat and Mo of the term "band aid" to describe EQing in live sound... literally correct.:D

Or if it was deliberate, you're very smart dudes....:thumbs up:
 
Armistice said:
I'm loving the (assumed) unintentional use by ashcat and Mo of the term "band aid" to describe EQing in live sound... literally correct.:D

Or if it was deliberate, you're very smart dudes....:thumbs up:
Click to expand...

For a festival it could be 30-band aid.
 
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