Beginners Auto EQ Questions

smurray

First off I want to preface this question by saying that I have searched and I have read the FAQs, and unfortunately I'm still confused about some things with the Auto EQ function of the DriveRack PA. We are using the PA at my church which meets in a school cafeteria each week. I went out and bought a dbx RTA mic because I thought using the auto EQ function of the DriveRack would allow us to zero out the main EQ on our Mackie mixer. I'm beginning to wonder whether or not this is actually the case.

I used to have a car stereo that had an Auto EQ function, and I made the mistake of thinking this would be as simple as that. When I went to use it yesterday I realized I had no idea what I was doing. I tried reading the manual as well as the FAQs here on the forum, but I'm still not sure how exactly to make this work.

My first question is whether or not I actually can use the Auto EQ to replace the EQ on the mixer. If I can, then what options should I be choosing between the Flat (0), and Response A-D, and Low, Medium and High Precision?

My second question is, how do I know what pink level to set the room at? It says to use the same level that I'll be using during the performance, but how do I know what level I'll be using during the performance?

And finally... When I did try and make it work yesterday, the Auto EQ never actually finished. I made some guesses on the settings and it started doing its thing, and I saw the progress bar move, but it never completed. When I would rotate between the two available screens I would see the progress bar go backwards. Eventually I had to manually stop the process. Is there supposed to be some sort of \"completed\" notification, or once it stops making changes does that mean it's done?

I apologize if any of these questions are stupid, I really am trying to understand. I've been thrown into the role of sound tech because I know the most out of anyone else in the church. Unfortunately that isn't saying much at all, and I have no idea how any of this is supposed to work.

Dra

I assume that you set-up your speakers every week? What are they? Where are they in to relation mics usage? Is there a lavalier in play here?
What is you goal? no feedback? Describe the room (size, wall and ceiling make-up, etc) Is there a recessed stage like many schools have? Are you using it?

Get back with these (and more) and we'll proceed.

DRA

Gadget

Ok, I'm not going to bust your chops but I don't think you actually read the FAQ's we are talking about...Now don't be offended but I'm going to point out the things that ARE in those FAQ's that answer your questions...here we go..

My first question is whether or not I actually can use the Auto EQ to replace the EQ on the mixer. If I can, then what options should I be choosing between the Flat (0), and Response A-D, and Low, Medium and High Precision?

Ok, you never did say WHAT mackie mixer.. and which EQ are you speaking of? If it's the channel eq's ...absolutely Not.. If the mixer has a GEQ it is limited to a few bands and is pretty useless, so yes the 28 band EQ or the 9 band PEQ will be WAY better...

My second question is, how do I know what pink level to set the room at? It says to use the same level that I'll be using during the performance, but how do I know what level I'll be using during the performance?

Well, the thing is the DRPA won't let you exceed the level that would peak the unit...in the rock and roll world we consider the process very painful... since it's usually as loud as the unit will let you go...for church purposes try going up to where it promps you to \"turn down\" the pink noise, and lower it 3-5 db and try that...(with some thoughts first though)

From the FAQ section here:
http://www.dbxpro.com/Forum/viewtopic.php?t=949

1. You CANNOT eq a room! Only a bulldozer can that.. which if you have read between the lines means if you knock down the walls….you get the picture.
2. An RTA based measurement system only takes into consideration volume based frequency specific information. Another problem is that the sampling of these frequencies is finite. This means that with a sampling of only 28 frequencies for the entire audible frequency range (20 hz to 20,000 hz), that huge numbers are completely ignored. I won’t get into to much detail about what frequencies are sampled, but they are considered “ISO centers� this means that a consortium of “audio professionals� got together and decided what frequencies a 1/3 octave EQ (28-31 bands) uses for its center frequencies. ( your center frequencies are 31.5hz, 40,50,63,80,100,125,160,200,250,315,400,500,630,800,1k,1.25k,1.5k,2k,3.15k,4k,5k,6.3k,8k,10k,12.5k, and 16k for the DRPA and 260… the 240, 400, and 4000 series have 31 bands…) this leaves HUGE gaps (for instance, 4K to 5K is 1000 hz! And EVERYTHING between 4000 and 5000hz is IGNORED completely!!!), and if you noticed the higher the frequency the larger the gaps…Instead of 1/3 octave the sampling rate should be more like 1/128th octave, or more (note…future generations will look back at our quaint sampling rates.. even 1/128 octave and snicker at the simplicity of our understanding of the technologies…) these huge blocks of ignored audio could hide comb filtering (if you don’t know what this is you need to do a Google, or other search to find out what it means) nulls, or modes that could and will adversely affect your sound reinforcement system in a room.

I go on to explain about mic position, room features, and all the nasty little things that can happen with the Auto EQ... So, after discussing the traps and pitfalls of the Auto EQ process this...is added:

So what CAN we do with the auto EQ? I suspect you’re sitting there thinking what good is this thing anyway? Well I asked myself the same thing. First off Mike Kovach ran side by side tests with a SMAART rig (FFT based measurement system we talked about earlier) and found that within the limited scope of the of the Auto EQ it was fairly accurate.

If you have been reading up on this site you know that we have discussed taking the system (one stack of speakers) outdoors away from all reflective surfaces and with the mic 8-10 feet out aimed at the space between the low and high components of the top cabinets, selecting the -0- precurve from the Auto EQ menu and establishing a baseline flat preset, that we can then store and recall for a number of purposes. ( note, here would be a good time to also set up a couple of the other precurves for later recall. The “C� curve was the one most preferred but I can see a potential use for the –A- and possibly the B, and C curves as well. ) The Idea hers is to make a pass and then view the product of the Auto EQ pass and then use the post (after) crossover PEQ’s to accomplish the same thing the GEQ did and then clear the GEQ and do another pass with the Auto EQ .. again use the remaining peq’s to get closer to a flat baseline until the product Auto EQ is essentially flat. (remember that speakers react differently the closer they get to their theoretical max output so try and test at your normal concert volume… the DRPA has some limitations here so work within these parameters)This we will store to a preset location (of your choosing, I usually choose a preset I will never use but the preset you replace is always still available in a hard reset to factory default …see your manual) with three presses of the store button where you will be asked to name the preset, select a location for it, and verify that you really want to replace the existing preset. This also presumes that you have read and done the steps in the Welcome “read me first� and start here threads…

Now we know that we should flatten the speaker as best we can, establish a preset and store this flat preset so we have a baseline...

What we have now is a system that outputs all frequencies equally (hopefully.. and of course within the limitations of the Auto EQ system). No hype to any frequencies, no lost frequencies that need to be boosted in order to correct for some system deficiency. Now, IF all frequencies are equal any vocal or instrument that sounds good in and of itself should sound essentially the same (or at least reasonably close if the system has quality components) when reinforced. You may want to boost the 80 hz (first harmonic of the kick drum, the actual center frequency is closer to 300-400hz) , and guitars are @ about 2k, vocal clarity 3.5K and if cymbals are piercing, lower the 7-12 k region. I have even sweetened a preset or two, set up a heavy metal, blues and light rock presets and stored those for recall since the more options you have when you’re under the gun the better chance you have of having a quick preset that is going to work for your situation.

And with this info what to do to perhaps sweeten the sound a little.. to taste...

The stored flat preset can also be used to evaluate what a room is doing to your sound… when we can actually DO an Auto EQ that is. I like to take the measurement mic and aim it at the floor or ceiling in the room. This eliminates a lot of potential reflections that will color the results, The mic should be no farther away from a surface than about ¼ of an inch, and aimed directly at the surface at 90 degrees to the surface. This then becomes a pressure zone microphone (PZM). Where do you put the mic? Well.. that’s a loaded question. The best thing is to take multiple measurements in varying locations and average the results. This can be somewhat challenging and so will interpreting the results of the Auto EQ passes. If your THAT interested in the measurement of your system may I again suggest you get into FFT measurement systems like SMAART, which, once you get up to speed can REALLY allow you to tune your system to it’s full potential. An adder bonus is the that SMAART is capable of working in conjunction with the Driverack system (not the DRPA though.. sorry)

This is what we can do with the stored flat preset.. and here:
http://www.dbxpro.com/Forum/viewtopic.php?t=953
is the BEST way to get a flat sound for your system...

Here is a further clarification of the process:
http://www.dbxpro.com/Forum/viewtopic.php?t=1617

Now, I would read the \"getting started\" post:
http://www.dbxpro.com/Forum/viewtopic.php?t=960

and I hope you started here:
http://www.dbxpro.com/Forum/viewtopic.php?t=959

So, with all this effort concentrated on the Auto EQ process I can't see how you didn't see any of this.. had you read THESE FAQ's?

BTW in there it clearly states that if \"More than 4 bands are fully CUT or BOOSTED\" the \"NOT Finished\" will be displayed.. if you have chosen to use DUAL mono, it will also display \"Not Finished\" ...It also tells you why.. the bands are cut or boosted...

More questions?
Gadget chief DRUG guy...(drive rack user group)

smurray

Thanks for the reply, and I can assure you I did read what you posted. The problem is (and I'm fully aware that it's MY problem and not anyone elses) is that even though I read it, I didn't understand much of it. I will go through and reread everything and see if I can't start making more sense of things.

As for your question about our soundboard, it's a Mackie CFX.MKII 16 channel mixer. We use the channel EQ's to tweak the individual channels, however the main EQ (9-band) for the board is also being used as well. I have no idea who set it where it's currently at, it was done way before I started running things and I just haven't attempted to make any changes since as I mentioned I'm still trying to learn as I go here. My hopes were that I could use the Auto EQ function of the driverack and zero out the main EQ on the board.

Dra

Dra wrote:

I assume that you set-up your speakers every week? What are they? Where are they in to relation mics usage? Is there a lavalier in play here?
What is you goal? no feedback? Describe the room (size, wall and ceiling make-up, etc) Is there a recessed stage like many schools have? Are you using it?

Get back with these (and more) and we'll proceed.

DRA

???

DRA

smurray

Yes we set up the speakers each week. We have a pair of Bose 802 Series II an a pair of Yamaha CW115v subs. Both the speakers and the subs are in the front two corners of the "stage" which is really a raised section of the cafeteria about 25ft wide and 10ft deep. The pastor uses a lavalier mic during the service, though it is mainly for recording purposes as he can easily be heard without it.

I don't have the exact dimensions of the room, and unfortunately any guess I make I'm sure would be way off. What I can say is we set up seating for about 130 people each week, and that gives us about 15-20 feet on all four sides of the chairs. The front and back walls are concrete, and the two sides are lockers. The front of the room (behind the stage from the left side wall to the right) we hang pipe and drape in order to hide as much as possible the fact that we're in a school cafeteria.

Our goal is to basically have our sound setup be as good as possible. There really wasn't anything "wrong" with how it sounded before, we just think it could probably sound better since we haven't done anything with the EQ on the DRPA.

Dra wrote:

I assume that you set-up your speakers every week? What are they? Where are they in to relation mics usage? Is there a lavalier in play here?
What is you goal? no feedback? Describe the room (size, wall and ceiling make-up, etc) Is there a recessed stage like many schools have? Are you using it?

Get back with these (and more) and we'll proceed.

DRA

Dennis

All lavaliers are evil. Talk Pastor into a Countryman E6 headset.

Dennis

Gadget

Bose 802 Series II an a pair of Yamaha CW115v subs

Ok so no horns...and no highs, no lows Bose...Why not try the \"new indoor method\" and see if you can't get a flat preset? After a pass even (when) it fails (with the bose you may not get away with a full pass .. it may not finish) press the 'preset' button then the \"EQ\" button and if it's not on the GEQ toggle to it.. see what the Auto EQ has done to the GEQ.. tell us what that is...

Did you say the side walls are curtained?

I think if you do the Indoor method.. and try that and get back to us...I think you'd be far ahead to try and keep the sound on the audience and off the walls and ceiling... which will prove difficult with the bose...

G

Dennis

Gadget said \"BTW in there it clearly states that if \"More than 4 bands are fully CUT or BOOSTED\" the \"NOT Finished\" will be displayed\"

My comment here might have been covered in one of the links above. If so, you will read it twice. If the auto EQ has fully cut or boosted a frequency, I would be suspicious the issue is caused, directly or indirectly, by a cancellation due to combing. This can't be corrected by EQ. It's a timing issue that you probably aren't yet ready to tackle. Try moving the mic a couple of feet, hopefully out of the cancellation(s) and try the auto EQ again.

Dennis

WitchsMark

All this time I have been playing our gigs using the Flat Response I did over a year ago. I just realized Gadget, that you are saying that now that I have gone through the pain staking ordeal of getting a flat response, this is just a baseline and now it is OK to season to taste by for instance boosting the 80Hz for the Kick drum to cut through better, etc etc. Our sound is already great with what we have been doing with no \"seasoning\" what-so-ever, I wonder if I can get it even better, for instance boosting the vocal frequency a little. My question is should I go ahead and perform another Gain Stage after boosting a frequency a little here and there or would I have to really up the decibels on a specific frequency to need to worry about it?? Once I get my EQ set to taste I will save it as a seperate Preset that the Flat. I know the FAQ says that you should re-do the GAin Stage process if you adjust the EQ, but I was wondering if that is really necessary if you only boost a little like within 3db??

Dr. J

Good question WitchsMark. I would like to know too about re-gaining. As far as the \"Flat\" system is concerned. I know you do that outside or the inside method to get the system tuned to the speakers that way when you go into a club your system is going to be tuned the best it can and now all you will have to deal with will be the \"Room\" rather than the speakers PLUS the room. In the FAQ section on \" Auto EQ How it is supposed to be\" and \"Auto EQ\" --- Gadget -- after tuning his system goes through the steps of using the RTA in the club where he places the RTA mic a quarter of an inch from the ceiling about 20 feet out (equidistant). He runs the RTA unit to measure the room. Keeps what the auto EQ does from about 170hz-700hz & then tunes ALL of the lower and upper frequencies by ear -- Letting his ears be the final judge. From there -- I am certain he \"SAVED\" it. He also repeated this process with a few of the other \"Pre-curves\" so he would have great starting points for a particular type of band. So from what I have read you can go ahead an run the RTA in a club if allowed to and only if you have set the system FLAT first -- which sounds like you did & keep the frequencies between 170hz and 700hz -- season to taste the upper and lower frequencies ex. boost 80hz for kick ...etc. and then \"SAVE\" those settings for that particular venue. It's done for that place and all you will have to do the next time will be minor tweaks (hopefully). Just in case you don't know and I am sure that you do know -- it is a great idea to save that \"Flat\" response for your system in a spot that you know you can always go and retrieve when needed. You will want to keep that in a safe place otherwise you will have to take \"A Stack\" back outside and do the whole thing over again. Ex. After I tuned my system --- I saved those settings in numerous other patches (actually I saved it in about 15 other presets). Until I change something in my system like speakers then this will be where my system needs to be and stay tuned at -- at all times. My default patch for this says: \"Flat Patch\" which tells me -- don't jack with it (or at least with the PEQ's). Hopefully I didn't confuse you WitchsMark. Here's a recap summary:
1. You tuned your system and saved the PEQ settings to where it made your GEQ show Flat.
2. Save the crap out of those settings -- this is your \"New BASE Default\" for your system. Don't let anyone mess with these. Save them everywhere in your DriveRack -- User patches)
3. Go into a venue and run the RTA -- save the settings from 170hz-700hz. Ignore the rest and use your ear to tweak those upper and lower frequencies. Make boost's where you see fit. ex. 80hz for kick..
4. SAVE those settings and Name it for that venue. You now have your system dialed in and ready for the next time you are there. ENJOY!

5. Next venue -- pull up another Flat Response patch from your saved settings (New BASE Default), RTA again if you can and do the procedure all over again...... Hope this helps and if anyone wants to add to this go for it and if I am way off -- someone please step in. Thanks!

Gadget

Like a proud pappa :P I think I'm tearing up a bit here 8) You guys are really making me proud...

Just a couple minor caveat/points...in the \"How it's supposed to work\" the key here was a room that was awesome to begin with, with only a few minor issues... probably the best room for music in a long long ways... The stage had rounded corners, was completely carpeted floor to ceiling, and the LABsubs were corner loaded... The tops were mirror image 40X60 pattern with seamless integration, and they crossed about 3 feet in front of the stage.. which offered plenty of buffer to the stage, but had lovely coverage. A room that I will perhaps never equal...I miss it badly...

So you might not get the same results(Your mileage may vary...)...ANY and ALL maxed out bands ARE SUSPECT!

YES with the PA.. store often and multiples are good.. but a hard copy of the settings is a MUST.. if you want to have a backup with the PA.. on the 200 series and up, an upload to the computer of the .dwp file will ensure a backup...

As for minor adjustments AFTER the gain structure.. mostly no.. I don't re-do BUT if something is considered \"suspect\" like a broad PEQ with a 2 or over gain... well...you have to make a judgment call if it's enough to cause the amp settings to become suspect...

Mark, I really don't find that I need to change the sound of the flat response for the most part. As I said I understand room acoustics and reflections, and standing waves and can make a judgment assumptions from the differences between the flat preset and any changes in the Auto EQ for the same room... that is NOT an easy task...and you should only attempt this if you think you to can make the calls... Minor seasoning shouldn't make a big change except in reverberant spaces.

Gadget

Dr. J

Thanks for the input Gadget! If it weren't for you -- I would still be chasing after those feedback frequencies on my little 15 band graphic EQ until I thoroughly destroyed all that was left that COULD have been useful! This is by the way -- the standard old school mentality here in these parts of the country. I just turned 40 this year and sound guys don't even want to talk to me anymore because I ask them if they have \"Flattened\" their system out. I am actually a guitarist and have been playing for quite some time and I really got into live sound systems because nobody can reproduce through a PA what is actually coming out of my 4x12 cab. It is frustrating to know that my incredibly warm tone with rich harmonic overtones is being completely destroyed out front with people saying the guitar is killing my eardrums from those horns! So I got fed-up and put together a PA -- bought a DriveRack PA and after my first month as a member here -- I had to totally throw out what I thought I knew about sound. Gadget WILL get you on the right path -- if you will listen. A buddy of mine who ran sound for bands 20 years ago was probably the most stubborn when it came to this -- but after SLOWLY going through the CONCEPTS here preached on the forum & EVERYTHING in the READ ME FIRST SECTION BEFORE POSTING -- he started to see the light or should I say started to hear the sound? Now when we play -- he can actually be creative rather than diagnose the whole night. AND he gets lots of compliments now! A big thanks to Gadget and I don't want to leave DRA out as he is very helpful as well.

Gadget

Amazing isn't it...A little knowledge goes a long way..doesn't it. 8) Good sound is no accident! The really cool thing about life right now.. is ...you can learn about anything you want! Ya, I ..we, have provided a number of good starting points ..especially for the Driverack platform. But even if you use a 223xl you can optimize your sound if you follow the advice.

Thanks J, I do work diligently to make sure that accurate advice and techniques are available, and without TOO much TECH overload...There IS a steep learning curve, and with the technology, a certain obligation follows... you need to understand the technology, and impliment it correctly. If you do, you get good sound, Its no accident.

Be well all...
G

WitchsMark

awesome thanks goes out to the both of you. I can't wait for our next gig now coming up in March so I can actually use my RTA for the first time other than when I used it to flatten the system to begin with. I have had my DRPA for a little over a year now and I keep finding I am still learning new things all the time. After I use the RTA at the next venue and tweak it out..... do you need to do a new Gain Structure with the new EQ settings??

Dr. J

W - From what Gadget stated in the above conversation -- it doesn't appear that you would need to do much (if anything) to the gain structure unless you have made some changes that are major.

Gadget says:

As for minor adjustments AFTER the gain structure.. mostly no.. I don't re-do BUT if something is considered \"suspect\" like a broad PEQ with a 2 or over gain... well...you have to make a judgment call if it's enough to cause the amp settings to become suspect...

Also about tweaking AFTER you set the system up flat:

Mark, I really don't find that I need to change the sound of the flat response for the most part. As I said I understand room acoustics and reflections, and standing waves and can make a judgment assumptions from the differences between the flat preset and any changes in the Auto EQ for the same room... that is NOT an easy task...and you should only attempt this if you think you to can make the calls... Minor seasoning shouldn't make a big change except in reverberant spaces.

One other thing Mark -- Keep in mind what Gadget said earlier after my initial take on the RTA thing. Gadget -- listed several things that made the room he was in a good candidate to even RTA in the first place. Here they are:

Just a couple minor caveat/points...in the \"How it's supposed to work\" the key here was a room that was awesome to begin with, with only a few minor issues... probably the best room for music in a long long ways... The stage had rounded corners, was completely carpeted floor to ceiling, and the LABsubs were corner loaded... The tops were mirror image 40X60 pattern with seamless integration, and they crossed about 3 feet in front of the stage.. which offered plenty of buffer to the stage, but had lovely coverage. A room that I will perhaps never equal...I miss it badly...

So you might not get the same results(Your mileage may vary...)...ANY and ALL maxed out bands ARE SUSPECT!

Anyway I know you want your system to be the best it can possibly be as all of us do but it may or may not be worth the hassle to go through the RTA in buildings that are horrible to begin with. We play a couple places where it is nothing but concrete on all of the walls & floor plus the ceiling is some kind of corrugated metal. Not a good room. I never bothered to RTA this place. Maybe I will sometime and just do a comparison but I am not sure much will change. Just do what Gadget says in one of his other threads: Keep the sound off the walls and on the people. Who cares about the guy in the back corner on the Poker machine.......ha. What we do when we go in places like I have described is put all cases (Drums, guitar, bass, cord cases....etc. and pile it up on the back wall and place a backdrop or some kind of curtain to try and reduce the reflections on that back wall. Particularly with our drummers SNARE drum. Another thing you could do that we all want anyway is to get everyone you know to come to your shows. The more people -- less reflections. Oh you also mentioned something about using compression on the house. Hmmm -- I better go over to that thread and help you there.