From DBX Indoor Auto EQ method

EQ guys are using on their cabs/systems. A good starting place if you don't have your own RTA.
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CBIERN
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From DBX Indoor Auto EQ method

#1 Post by CBIERN »

I used this 6 years ago to establish the baseline eq for my DR250s. It's still my preset and still seems to work in all the rooms we play.

http://www.dbxpro.com/forum/viewtopic.php?f=60&t=2908
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Charles Jenkinson
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Re: From DBX Indoor Auto EQ method

#2 Post by Charles Jenkinson »

I'm glad you posted this (and the other link). I need to get to grips with it and migrate from a 31 band manual EQ over to the PA+ I have under the spare bed. I suppose I have some specific questions and some general ones, just to get my head round the overall approach - they are not necessarily directed at you. :-)

Is that what you actually did?, i.e. auto-EQ using the PZM floor mic (close, indoor) method and then set those results into the PEQ (getting a default flat response for the cab), thus freeing up the GEQ on auto-EQ (RTA) to tell you 'what the room does' in any new venue.

On the subject of the manual corrections:
How do you go on doing the 'manual corrections' he talks about in the venue, on the back of not trusting an auto-EQ result? Did you do any 'training' to discern the manual correction approach or pick it up over time? I find it very hard to discern the effect of what adjusting one band does to an overall sound, when the context of a sound one is hearing is always the 'overall sound'. I fancy the F Alton Everest Critical Listening skills (book & CD), if that's a suitable training approach to the task of manual tuning...? I've previously had difficulty finding the Mike Kovach 'white paper' referred - is the consensus that it might be this one...?:

http://www.dbxpro.com/forum/viewtopic.php?t=957

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Charles
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Grant Bunter
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Re: From DBX Indoor Auto EQ method

#3 Post by Grant Bunter »

Charles,
Manual adjustment is simply best defined as adjusting to taste.
As a generalisation, RTAing is about a flat response.
But many say a flat response can sound "sterile".
A few (manual) tweaks of a flat response after RTAing can change that to eg "warm".
It's hard at first, just play around with it until you get something that sounds good to you.
That will change with time.
And if you have it saved, you don't have to remember what it was, if you totally "ruin" it, just hit the recall button...
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Re: From DBX Indoor Auto EQ method

#4 Post by Michael Murphy »

CJ, After running the auto eq to flat I modified the same curve to my liking, just as grant said, its a couple of push on the wheel, page up or down to get in to adjust the eq manually, I never remember exactly the steps but it comes to me after a few push/turns on the data wheel. When you get it to where you like it hit store, it will have lit up red (the button) any time you make a change to the settings. This also happens when in cross over mode, or any mode you are in and change a setting, i.e the store button will turn on red indicating for you to press and store the changes. Friend came over one day I was playing and I made a quick change on the x over and continued, he said you know that thing pretty good now :) Little does he know Ive only just scratched the surface :o

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Charles Jenkinson
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Re: From DBX Indoor Auto EQ method

#5 Post by Charles Jenkinson »

I had to read that article on the DBX forums a few times before I got what he was saying. He's talking about getting the system flat by manually setting the results of an RTA (done outside) into the PEQ (the parametric EQ), which is a different part of the PA+ than the General EQ (the GEQ is used and set during an RTA). Once this is done, on a subsequent RTA (again done outside) the GEQ should be flat if the PEQ has been been set to flatten the speakers properly. If you then take the system indoors and run RTA it tells you what the room is doing.

I know I keep banging on about this (apologies :D ), but I'm not confident in the feedback I'm getting from current PA+ (forum) users. It's not my right to expect feedback, it's just all part of being on the planet together, and I want everyone to be up there with the DBX Gadget bloke. :)

Is that how you do it Jose?
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Re: From DBX Indoor Auto EQ method

#6 Post by Bruce Weldy »

Charles Jenkinson wrote:I had to read that article on the DBX forums a few times before I got what he was saying. He's talking about getting the system flat by manually setting the results of an RTA (done outside) into the PEQ (the parametric EQ), which is a different part of the PA+ than the General EQ (the GEQ is used and set during an RTA). Once this is done, on a subsequent RTA (again done outside) the GEQ should be flat if the PEQ has been been set to flatten the speakers properly. If you then take the system indoors and run RTA it tells you what the room is doing.

I know I keep banging on about this (apologies :D ), but I'm not confident in the feedback I'm getting from current PA+ (forum) users. It's not my right to expect feedback, it's just all part of being on the planet together, and I want everyone to be up there with the DBX Gadget bloke. :)

Is that how you do it Jose?

Instead of an outside RTA, you could run the auto EQ, draw it out on paper where the boosts and cuts are....and how much....then try to recreate that in the PEQ. Then you'd run the auto EQ again and see what it corrects - then go tweak the PEQ again. You won't get it totally flat with a few bands of PEQ.

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Re: From DBX Indoor Auto EQ method

#7 Post by racertomtom »

Bruce Weldy wrote:
Charles Jenkinson wrote:I had to read that article on the DBX forums a few times before I got what he was saying. He's talking about getting the system flat by manually setting the results of an RTA (done outside) into the PEQ (the parametric EQ), which is a different part of the PA+ than the General EQ (the GEQ is used and set during an RTA). Once this is done, on a subsequent RTA (again done outside) the GEQ should be flat if the PEQ has been been set to flatten the speakers properly. If you then take the system indoors and run RTA it tells you what the room is doing.

I know I keep banging on about this (apologies :D ), but I'm not confident in the feedback I'm getting from current PA+ (forum) users. It's not my right to expect feedback, it's just all part of being on the planet together, and I want everyone to be up there with the DBX Gadget bloke. :)

Is that how you do it Jose?

Instead of an outside RTA, you could run the auto EQ, draw it out on paper where the boosts and cuts are....and how much....then try to recreate that in the PEQ. Then you'd run the auto EQ again and see what it corrects - then go tweak the PEQ again. You won't get it totally flat with a few bands of PEQ.
I understand what we’re doing here but I’m not sure why. I don’t know about the PA+ but I think the DRPA and the DEQ2496 use PEQ filters for feedback suppression. So, if you use up all the PEQs to flatten response, you won’t have any available for feedback suppression. Not a big deal if you are a DJ not using any mics at all, but I wouldn’t leave my FOH completely vulnerable with mics in use.
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Re: From DBX Indoor Auto EQ method

#8 Post by Charles Jenkinson »

I think the 'why it's done' is to separate the 'room effects' on speaker response out on their own, so tweaking the EQ bands that apparently have to be done manually is more intuitive (because its quicker and easier to assess the effects of the room if they are superposed onto a 'flat' baseline starting point), rather than having to work out the extra additions or subtractions on an already hilly GEQ setting.

You raise a very good point though racerT. The manual shows a block diagram layout of signal routing, showing how it goes through the GEQ, crossover, PEQ, etc. - all very nicely, but it's not at all clear what functionalities the wizards/utilities require access to and usage of. If a piece of equipment needs a forum and numerous in-depth debates to understand or utilise to its full potential, then something is not right somewhere, perhaps something as simple as the manual being wholly inadequate.

I'm gonna have a day of reckoning with the PA+ (and hopefully answer this issue you've raised in the meantime), but for now it's planning a pair of T30's build and tidying the garage.

I could be making more of this than I ought, but I have genuinely learnt something through reading the DBX articles and studying a little further. I do like the PZM (boundary mic) technique for RTA'ing the speakers. I got a bit of revelation on the phase drop-out errors (due to reflections) that probably led to a 'thin/odd' sound I got some time ago whilst recording violin tracks for a mate's album, using a RODE NT2A in my bedroom (hard ceilings and walls in close-ish proximity) on a mic stand - the recorded violin didn't sound like my violin where I hear it whilst playing, so I assumed that the recorded sound was just the sound further away where the mic was. I'd have got a better recording either absorbing some of the sound so it didn't reflect or just using a boundary mic screwed on a 2ft diameter piece of plywood, 3 or 4 ft away.
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Re: From DBX Indoor Auto EQ method

#9 Post by Bruce Weldy »

racertomtom wrote: I understand what we’re doing here but I’m not sure why. I don’t know about the PA+ but I think the DRPA and the DEQ2496 use PEQ filters for feedback suppression. So, if you use up all the PEQs to flatten response, you won’t have any available for feedback suppression. Not a big deal if you are a DJ not using any mics at all, but I wouldn’t leave my FOH completely vulnerable with mics in use.
The dbx units do not use the PEQ for feedback suppression. If they do, it's not mentioned anywhere in the manual....

I don't know about the DEQ2596...

As far as what he's trying to do - I understand it, I just don't do it that way. If you are going to auto-EQ the system for each venue anyway, why not just save the GEQ once it's set for the venue...and go with that each time? You may be a little more accurate by doing both - but I don't know if it's worth it.

I kinda' achieve the same thing by having a flat setting on my DRPA+ and then EQ the room with the Presonus Board and SMAART software.

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Re: From DBX Indoor Auto EQ method

#10 Post by racertomtom »

Charles Jenkinson wrote:I think the 'why it's done' is to separate the 'room effects' on speaker response out on their own, so tweaking the EQ bands that apparently have to be done manually is more intuitive (because its quicker and easier to assess the effects of the room if they are superposed onto a 'flat' baseline starting point), rather than having to work out the extra additions or subtractions on an already hilly GEQ setting.
That makes sense but considering the limited number of PEQ filters I'm wondering how useful it actually is.
Bruce Weldy wrote: The dbx units do not use the PEQ for feedback suppression. If they do, it's not mentioned anywhere in the manual....

I don't know about the DEQ2596...
I know the 2496 shares filters and I thought the DBX did as well, but my high mileage '70s brain could be mistaken. :fruit:
Bruce Weldy wrote: If you are going to auto-EQ the system for each venue anyway, why not just save the GEQ once it's set for the venue...and go with that each time? You may be a little more accurate by doing both - but I don't know if it's worth it.
+1
I kinda' achieve the same thing by having a flat setting on my DRPA+ and then EQ the room with the Presonus Board and SMAART software.
IMO this is the best approach. More or less what I do only I'm still in an analog world using my ears. :fingers:
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Re: From DBX Indoor Auto EQ method

#11 Post by Bruce Weldy »

racertomtom wrote:I'm still in an analog world using my ears. :fingers:
Yeah, that's what I was doing too.....thought mine were pretty good. uhhhhhh......not as good as I thought. The SMAART software has really made a difference with the rock band I work with. It's clean up some low mids that I wasn't catching.

Gettin' old is hell.

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Re: From DBX Indoor Auto EQ method

#12 Post by CBIERN »

At what point do you folks, who are auto-eqing each venue, hit the place with 90db of pink noise? Granted you can store the results for next time but don't you get complaints from the existing clientele?
Of course it can't be that much more annoying than 10 min. of "test...test.... testing 1" etc. as each band member gets added into the mix
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Re: From DBX Indoor Auto EQ method

#13 Post by racertomtom »

I can't even get my band to not yell WTF! I gave up on pinking a room and go in flat and tweak the board PEQs during the first couple of songs. Even if I can get cooperation with bar managers and patrons, Mic placement usually makes matters worse than flat.
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Re: From DBX Indoor Auto EQ method

#14 Post by Bruce Weldy »

CBIERN wrote:At what point do you folks, who are auto-eqing each venue, hit the place with 90db of pink noise? Granted you can store the results for next time but don't you get complaints from the existing clientele?
Of course it can't be that much more annoying than 10 min. of "test...test.... testing 1" etc. as each band member gets added into the mix

Fortunately, almost everything I do is before anyone shows up. But, the DRPA+ is very fast. Where the original DRPA took up to a minute or more, the new one is about 10 seconds with it set on medium.

Ask the bar owners if you can come set up early and analyze the room....then you're done. If not....ya gotta' wing it with some setup music.

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