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EQ to a venue? The basics?!


MisterJames

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Morning Guys...

 

 

Right... I used to be very interested in lighting and had only known the basics about sound... as from a year ago ive slowly slid into sound as ive love live audio, concerts, classical concerts. But! ive never properly understood how to EQ the Graphic EQ's (detailed one, not on the mixer) to a set venue... when I do it I end up with most the sliders where on 0Db :| but obviously professional ahev them all over the place. What am I listening for? what does the sound need to sound like...

 

I understand how use the EQ on mixer to cut down on feedback... Thats about it.. well obvious speaker placement, And general things...

 

 

Can anyone give me quick writen guide to EQ'ing?

 

Cheer

 

James

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If you have access to a 20 to 20,000HZ sweep tone - the alan parsons test disc is a handy source of useful test signals - run it through your system in the venue. You'll find if you're unlucky that certain frequencies as the tone progresses jump out, or get quiet. At the most basic level of eq - you set the curve to reduce the honky ones, and put back ones that are missing. Feedback at quite low overall volumes makes sense when you realise the venue acoustics conspire against you like this. Just a tad of output at the frequency with the big natural peak is a major contributor to early feedback. This gives you those odd curves you see sometimes -BUT - they are different for every venue. Plenty of people use the 32 band 1/3rd octave graphics as a glorified tone control - not as equalisation. They travel with this curve permanently set. Used for monitor feedback suppression, people often notch out problem frequencies - but of course, this leaves the overall sound quite different from the original. There are also clever software/hardware combos tha to some degree automate the process, or at the very least, let you see what you are hearing. After that, it's experience and skill to get the best results, as one adjustment often means some kind of compromise somewhere else.
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Having all the sliders on a GEQ at 0db is not bad! The what your listening for is odd/nasty/problem frequencies which need to be cut or boosted according to how you think it should sound as your the one in control. The easiest way to do it is to put on a cd you know inside out as to how it should sound then raise and lower each band of the graphic until it sounds right to you in the room ( noting what each cut and boost at each frequency sounds like). The more you do it the more you will train your ears to listen and identify these frequencies and deal with them. Once you've got an idea of how it works in an analogue world then he displays in software will make more sense. For what its worth the sft feedback trainer is really worth its weight for basic ear training
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... The easiest way to do it is to put on a cd you know inside out ...

I would disagree this one. What should the CD sound like? the cheap crappy pair of PC speakers you listen to a heavy compressed mp3 on.

The best way to eq a system is plug in a mic(the main one you are using for vocals) and talk down it with your own voice. What you are looking for is to make it sound 'nice'. You know your own voice better than any one, so it should sound as much like your own voice as possible with as flat an eq on the channel as possible. My general rule is trust your ears.

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....talk down it with your own voice. What you are looking for is to make it sound 'nice'. You know your own voice better than any one, so it should sound as much like your own voice as possible...

 

Hmm

 

My understanding was that most of the time I hear my own voice it is heavily coloured by the fact that I am also 'hearing' sound through vibrations within my head and therefore the perception I have of what my voice sounds like is different to the perception that anyone else has of what my voice sounds like. Therefore, if I set a system to make my voice sound like I think my voice normally sounds, surely it will actually be wrong, and at best very subjective?

 

Surely it is best, when 'EQing' a room to use the scientific and objective approach, as said previously of using sweep tones/pink noise to help detect resonant frequencies within the room and reduce them, whilst boosting frequencies that 'dissappear'?

 

I would argue that after that is done, then is the time to check if your voice or music sounds 'nice' and then adjust for taste.

 

My opinion

 

Andy

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Oh James, you've opened a can of worms here!! ha ha. This topic can and will go round and round for eternity. Simply put, there are lots of different ways of EQ'ing a room, and the above options are just a handful. Each engineer will have their own method they prefer.

Personally I use the main vocal mic, shout a few ones, twos and check checks into it and see what the room does at the level I'll need for the gig, with a bit added on for good luck. Any frequencies that seem to jump out at me, I'll recreate with my voice and notch them on the EQ until it calms down. If I can get the mic level I want without touching the Graphic, then I'm super happy. I then use the sound check to see if anything else jumps out at me that my voice didn't show up. I also try not to take a huge amount out in an empty room, because when it (hopefully) fills up with people, I'll need to put huge chunks of it back in.

 

Interestingly, nearly everytime we have visiting engineers in the venue I mainly work who use the sweep tone, they always seem to cut huge chunks out the graphic and spend the whole gig looking for audio that isn't there because they took it away on the EQ. Don't get me wrong, there are some engineers who REALLY know how to use that method and systems sound great when done right.

 

Like I've said above though, each person will have their prefered way of doing things. I say if you are leaving most at 0db and not having issues, then leave it alone. You should know when something isn't right - use your ears.

 

Have a wee look on Youtube for the soundcraft videos. I'm sure there will be something in that lot to help you.

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Ok heres how I do it.

 

First step : earplugs in!

 

- Maybe have two or three open vocal mics. Set them all the same gain.

- Bring up the gain on the 31 band EQ until the first frequency feeds back. Now, you'll need some reference points in your head to work out where abouts in the spectrum your looking for. Theres no medals for getting it first time so don't worry if it takes pulling down 5 or 6 sliders to get there.

- Now the trick is to take the slider down up until the point it stops feeding back, not -12db down!! (I have seen so many 'pro' engineers totally eliminate more than requried of a single band)

- Once you've cut out say two or three of the main offenders try out the vocal mics. Get them near the max gain before feedback. Loud enough?

- The EQ BYPASS switch is your friend. Whack on your Mp3 player of your favourite tune. Crank up the volume and then flick between bypass on/off on the EQ. With your changes engaged the music should sound loads better!

- The Finishing touch is just EQing to taste.

 

The Good news? When the room is full of people your gain before feedback is massively increased!

 

The Bad news? Your EQ settings aren't as relevant as they were in the empty room. Generally I don't risk changing the FOH EQ after soundchecks unless they are very high frequencies that I am certain will be totally absorbed.

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Just a quick 2p's worth. The OP admits he's new to this. Therefore I think the Cd appraoch for him would be better than his voiceas per Pyramids comment.I can see where Aidso is coming from but I think we can credit the Op with a little bit of common sense and hope he can tell the difference between a well produced commercial cd and a tenth gen copy of now thats what I call pap. I would also advise great caution when using sweeps in a room with the PA at full chat, as Phil says "earplugs in", its the hf which not only is going to hurt but stay with you for a couple of days and anyone else in the room.

 

To further stick my neck, out my current "test" tracks are Black Mambazo with Paul Simons Diamonds on the souls of her shoes and Nickleback This is how you remind me with the proviso I'm mainly doing concerts and gigs as opposed to theatre.

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Youre equ-ing two things, the speakers and the room. Some speakers (d&b, Nexo) need only little correction, others a lot more. Buy the Souncheck CD, then plug the flattest condensor you have into the desk, pfl it, and adjust gain until 1K tone gives you 0db on the meter. Then run through the frequencies and you'll see where the peaks and troughs are. It's not totally accurate, but can be a great help in finding the problem areas. Room problems are usually in the lower mid-range, or some high mid frequencies if a lot of hard surfaces. You'll find the speaker innacuracies will show up in the same areas every time you do this, room frequencies will vary. But rely mainly on your ears listening to stuff you know intimately. And don't over-equ !
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1. Find a Track which isn't compressed - and you like....

2. Play it through the system

3. Does it sound like what you expected?

4. EQ it to suit.

 

 

Option B is to use a system which is so good it doesn't need to be EQ'd!

 

If your on monitors, get a person to speak into the mic at different levels and see where it starts to feed back, adjust the EQ to suit.

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Do what is required to make it sound right!!!!! There are lots of different ways to go about EQing and the bottom line is that we are here to make the sound system, whatever it is we are faced with, work as well as possible and sound as good as possible. There are a few posts here that are talking about room or system equalization and some focusing on feedback elimination. Both of which might or might not be required. If there are big problems with feedback then the system design, implementation or management settings may be wrong from the start! if this is the case then it may be that the system needs to be looked at. EQing the system and room is a very personal thing, some people play CD's some use a mic some use other methods. Some people look at what the graphic 'should' look like, whats going on there? We are in the business of sound, listen to it, play with it until it sounds right to you. It makes no difference what you do or how you do it (as long as your basic gain structure remains good throughout). Experience is the only way to learn this one. try everything and find out what works for you. As with most things audio there is no right and wrong way, there is your way and my way (and yes there are some things that you do really need to do a certain way but this isn't one of them). If you end up with all the frequencies at 0dB then thats great! Have fun trying it all out, if it sounds right then it is right!
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