Equalisers?

[DanMerc]

Hello

 

I'm Dan and I'm a 15 year old audio and lightining technician at my high school.

 

I have a question. On our powered mixer, how should I set the equaliser to the right level?

 

From what I've been told by previous technicians and teachers is that no one has ever touched it.It's currently in a wave shape, like an 'S' rotated 90 degrees.

 

We have had our theatre refurbished over the summer and the room is now bigger, with some walls knocked down, some false walls put in, etc. so I'm sure the acoustics have changed and the equaliser may need adjusting accordingly. I am right aren't I?

 

I need a way I can do it basically without buying extra equipment or anything like that.

 

:biggrin:

Hope someone can point me in the right direction,

Danny

[The Boogie Man]

Hi DanMerc,

 

Your eq can be two things, a way to shape a sound to what you like, or a last in line defence against bad sound.

If it is the only eq you have then I'd make it a nice flat line and then use it at the time of a performance to just cut any rogue freq a bit.

If you have a dedicated eq further down the chain then it can be shaped to make the incoming signal sound better. (but it will be different for each type of signal.

HtH.

 

baz

[DanMerc]

Hey baz

 

Thanks for your quick reply

 

It's the only equaliser in the set up

 

All the mics and lines come into our powered mixer, and go from there to the speakers.

 

Most eqs I see are on a flat line, so I was curious as to why ours have been on a wavey shape for the past 15-16 years, despite the theatre being refurbished and rebuilt a good few times.

 

Dan

[Peter Chivers]

Hi DanMerc

and also welcome to the Blue Room. :biggrin:

There are several 'common' curves found on graphic equalisers, variations of the flat S and 'smiles' being among the most common. The usual reason they are there is that someone has set the overall sound to a type of sound that they particularly like, often with little regard to the actual room acoustics, or the requirements of what is being amplified.

I'll second the Boogie Man's suggestion to flatten it completely (to the central point on each slide) and then adjust while in use, if required - please remember that no adjustment may actually be required.

I have done several installs into concert rooms, usually in social clubs, where after setting the system up, the graphic on the powered desk has been flat because no tailoring has actually been needed. I have also done some where a separate 31 band graphic has been installed because the acoustics were such that detailed tuning was required! ( And I usually try and get that put behind a locked door!)

[DanMerc]

Cheers Peter

 

I will suggest it to my music teacher. She will probably go with whatever I say.

 

Before we had the theatre refurbished, we had a proper wooden stage and on the wall backstage was a box to connect up to 12 XLR mics. It fed through to the mixer on the other side through a huge cable labelled "DESK TAILS".

 

Since, it's now one large hall with portable stage blocks. The box for the microphones have been ripped out and the mics are now directly fed into the mixer.

 

Yet, she and the assistant audio technician plugged in the desk tails into the wall, and put all 12 XLR cables into the mixer.

 

They were a bit shocked when I kindly pointed out they were now useless and went to nowhere!

 

Slightly off topic, but the assistant audio technician has also tried to attempt to take my role as chief audio technician (long story) and yesterday I asked him for a stereo jack-to-jack lead and he kept passing me mono ones, to which I kept saying "wrong" to. He finally goes "how do you tell the difference?!".

 

Does anyone else have to deal with people who think they know better than you when they in fact know very little?

 

I am always open to discussion on decisions I make and I don't assume I know everything. Otherwise I wouldn't have registered here and asked for answers and advice!

[Dj Dunc]

Oh boy. I had the same problem. with an ex 6th former who came back as a chief technician, who managed to get the drama teacher hooked round his little finger, spec a new and crap computer at horrendous price and limited functionability, and promtly ruin it. amongst other lighting equipment. he also said that he had professionally eq'd the room. a) it was useless, and b) he handnt patched it in.

 

dunc

[The Boogie Man]

If the school has the budget for new gear in the future,as you've only got the one eq, I would look into getting at least one other. The eq's on desks are ( alot of the time ) only an add on to help sell a low end desk. Don't get me wrong a lot of good desks have very good eq added, but a really good desk will have a very good eq "strip" ( the vertical tone shaping section ) to shape the individual inputs and don't have another eq as it is assumed that a dedicated one will be further down the chain.

 

An eq to "shape" the sound after the mixer is a handy tool and can be as cheep and cheerful as a behringer tube eq.

Last in line just before the power amps is a good place to put something (again cheap and cheerful ) like a behringer fbeq 6200. This is an eq with lights on the faders that get brighter as howl around starts to build. Great for correcting a room to what sounds best for the particular show or gig. Or for setting the room to neutral then, as Peter suggests, locking out of the way of meddlers.

 

Both are nice add ons, but not absolutely essential. If it sounds ok with whats there, left flat then thats ok.

 

If you ever do gigs with monitors onstage then this is another good spot for a simple eq, not for shaping the sound as such ,but for controlling the signals that are being sent back to the performers. Which can get a bit wild with all the background noise on stage being re-amplified.

 

baz

[paulears]

I think that to most people, the graphic on a powered mixer isn't used to solve feedback or cut or boost specific frequencies as most are not narrow enough to really do this that well. So they just get used as a clever tone control, as found on hi-fi systems - so the familiar smiley face curve that boosts bass and HF kind of sound ok. In truth, if used this way, with music sources thay can make the room sound a bit better. People get to like a sound overall, and using the eq this way does the job. Specific adjustment at 3rd octave spacing allows for adjustment in far more precise ways, but the end purpose is different. One is control, the other is tone.

[Bobbsy]

Well put, paulears. The limited graphic EQ provided on most powered mixers is just a glorified "tone" control and nowhere near precise enough to allow any meaningful adjustments. As somebody else has said, chances are you'll do best just to set them all to "flat" and ignore them. The only thing to watch out for is that some people may have become used to the somewhat un-natural sound you may have now. On the other hand (depending on the results you're getting) people may notice an immediate improvement! Who knows?

 

Just to be a bit pedantic about one of your earlier posts, you may have had it wrong when you were asking for a "stereo jack to jack". Although this connector CAN be used for stereo, it can also be used for a mono, balanced signal and if you were plugging into a mixer that's almost certainly what you were doing. The actual connector is a "quarter inch TRS", the TRS standing for "Tip/Ring/Sleeve", to differentiate from a "TS" (Tip/Sleeve) which is what you mean by mono.

 

Yeah...I sometimes call them stereo jacks too...but "stereo" is a potential USE of that type of connector, not the name of the connector!

 

Bob

[The Boogie Man]

Once again, I become a little wiser.

Cheers Bob.

[bruce]

Just to be a bit pedantic about one of your earlier posts, you may have had it wrong when you were asking for a "stereo jack to jack".

 

Fully agree with what bob is saying - but to be even more pedantic/obscure/whatever, if someone asked me for a "stereo jack to jack", my immediate reaction would be to hand them a duplex cable - ie a cable with 2x TS jacks on each end....

 

but it's an ambiguous statement...

[DanMerc]

Hey

 

I was thinking about what Bobbsy said about people getting used to the unnatural sound. It's been like that since it was set up about 16/17 years ago and just stayed that way due to ignorance and the fact that none of the previous audio techs have known what it does and just left it.

 

Sorry, I didn't know the correct terminology! :( I was just told the end of unbalanced cables are called jacks, and the one with the 3 metal bits are stereo ones.

 

The guy who I was asking didn't know the difference between mono and stereo sound. He also didn't know what an XLR connection was. I think if I asked him for a quarter inch TRS he might think I was asking for something else! :P

 

Dan

[Bobbsy]

Sorry, I didn't know the correct terminology! :( I was just told the end of unbalanced cables are called jacks, and the one with the 3 metal bits are stereo ones.

 

Strictly speaking, the dictionary definition of a jack is:

 

a connecting device in an electrical circuit

 

By that definition, you can have XLR jacks, quarter inch jacks, phono jacks, BPO jacks, etc. I guess you could even call the mains plug a 13amp jack (though the confusion THIS would cause would not be fun...see threads on "widowmakers").

 

The more important thing to make sure everyone is aware of is that, just because your "jack" has three connections, other than for headphones, these are rarely used for stereo in professional audio. Much more commonly, it means a balanced circuit (if you haven't done so already, do some Wiki-ing on balanced vs. unbalanced...very important) or, perhaps, the mixer end of an insert cable. I'm only getting pedantic because, all too often, I've seen students assume that, because it was a "stereo jack", they were getting stereo into their mixer. In reality, they were either getting only one channel of a stereo source or a summed mono feed with possible phase cancellations (depending on how the cable was wired).

 

Well, I'm also getting pedantic because I'm a boring old git, but that's another story.

 

Bob

[greenalien]

If you have access to a PC with internet access, you could try downloading the free MP3 player,Winamp. This has a 10-band equaliser included, together with a number of presets - Dance, Reggae, Large Hall, Club etc. By playing a piece of music you are familiar with, you can see how the different presets affect the sound, then try your own adjustments ; you can then apply what you have learned to your desk.

[DanMerc]

Thanks for your help and advice guys.

 

I've just got back from the first night of our school's Christmas Concert and I'm utterly p***ed off.

 

We have a couple of radio mics and we allow people to use them if they ask us and we think it's appropriate. We then include it in our technical script.

 

But, no, let's just take the mics off the desk without asking. Let's give it to someone else without saying anything to the techs.

 

Oh, but the best one of all, was "let's take it into the toilets and leave it by the sink!" We were running around like headless chickens for a missing mic that someone had left in the toilet!

 

The worst of it is that the audio and lighting is ridicolous as it is done from the left of the stage. Yes ladies and gents, we aren't at the back or even mid way down the hall, we are at the left of the stage. Best place to see where the lights fall and being directly underneath a speaker is the best place to hear what the audience hears.

 

When something goes wrong, it usually isn't our fault, yet we have 50+ heads turn left and glare at us. Then the audience follows suit. We're stood there feeling like complete t*ts when someone has switched their microphone off, thinking they had turned it on. Short of me walking in front of the stage, going over there, turning it on and walking back, there's not a great deal we can do. But we'll blame the techs anyway!

 

My 2 possible solutions are (ruling out having the wireless mics on stands - teacher won't allow it) is to either stick to my script, and if someone has taken a mic without telling us, leave it switched off and go with the script, or just refuse to use wireless mics altogether (which is slightly unfair on the small minority who cooperate with us).

 

Any advice, tips, suggestions?

 

Do you just let this roll off your back? If you were being stared at by 200 people for something out of your control, would you too feel annoyed?

 

Thanks,

A very frustrated Dan