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Gig report...and a question

tado921tado921 Posts: 16
edited July 2011 in PA General Discussion
I was asked to provide the PA for a friend's band. Their bassist, who owned the band's PA, had quit suddenly and they had a gig coming up. I agreed, but I was nervous about it since I had never been a "soundman". Also, I had just performed the "outdoor method" to dial-in my rig. I had the GEQ settings to flatten the system, but had not setup the PEQ yet.

I decided to just go with the GEQ settings and adjust on the fly. The venue was a small bar but they had a good crowd, maybe 100 people. To make it short, the PA sounded GREAT and they were a good band. We had the house rockin all night, people dancing to just about every song. The bartender came up to me and said "You really know what you are doing. This is the best sounding band we've had in here in a long time!" I didn't adjust the EQ at all, just rode the faders to control volume.

Not bad for winging it, but I owe it to the DRPA and the advice I got here. :)

Now the question: I ran the rig with GEQ turned on and setup with the wizard settings. From my reading on this forum, the general advice is to translate the GEQ settings into the PEQ, and use the graphic to adjust to the venue. I am having trouble getting the PEQ setup so that the system is flat (using outdoor method again). Can someone give me a starting point on the PEQ given the GEQ settings below?

Note: Peavey PR12 tops/PV118 subs in mono, GSC GX5 power amp, xover at 100hz.
31.5 40 50 63 80 100 125 160 200 250 315 400 500 630 800 1K 1.25K 1.60K 2K 2.5K 3.15K 4K 5K 6.30K 8K 10K 12.5K 16K
---- -- -- -- -- --- --- --- --- --- --- --- --- --- --- -- ----- ----- -- ---- ----- -- -- ----- -- --- ----- ---
  0   0 +3 +3 +3  +3  +3  +3 -.5  -3  -3  +3  -4  0   -1 +1   +1    +3  +3  -2    +1  +3 +3  -1   +3  -3   0    0

Any help or advice is appreciated.

Thanks!

Tad

Comments

  • DraDra Posts: 3,777
    Well first you have more areas of need than you have PEQ's available, so you must choose what needs the most help. A couple of things to remember...

    1 - GEQ's do a bad job of "boosting" so concentrate using the PEQ's on the weak response areas (shown as +dbs on the GEQ plot), saving the hyped responses for the GEQ to cut (shown as -dbs on the plot).

    2- You have a consistent +3db boost on the subs (and on through 160). Something to consider... raise the x-over to 125 (or possibly closer to 150hz) then re-shoot and check the plot. Assuming that you have the amps set to proper gain structure go ahead and turn down the amp for the tops 3 db before re-shooting. You can also apply a shelf to the subs, but that will force you to reduce the amp (to not clip) and end up at the same place.

    3 - You have 3 PEQ's for everything above the x-over point. The rest is trial & error and will take a lot of tests that you will just have to do. Just pick an area and make a change and see what happens. Chart every plot and with what settings you used. It will be a great learning experience for you, but one that needs to be happen.

    4 - Work on trends in response. +1, +2, +2, +3, +1 not +3, -4, +2, -2

    5 - Remember, the Auto EQ plot is the correction, not the raw response. + readings will be +gain on the PEQ, - readings will be - gain.

    DRA
  • GadgetGadget Posts: 4,915
    My opinion is there are far too few PEQ's to do any good.. here or otherwise unless there is a MAJOR cut or boost across many EQ bands...

    I usually just eval the GEQ cuts and boosts and see if they are reasonable and actually contribute to better sound (see "cancellations" in particular)

    Then I use the PEQ's for general room charismatics adjustment...for on the 250 -500hz range can have a howling effect, and front loaded subs usually exhibit a peak @ around 60hz . These are perfect candidates for the PEQ's You can also add a high shelf and use it to tailor the highs..

    Gadget
  • tado921tado921 Posts: 16
    Thanks for the advice. :)

    DRA, I understand your points and will play around with the system. Let's hope I don't crash and burn on this learning curve. :mrgreen:

    Gadget, what would you consider "MAJOR"? Except for the -4 cut at 500hz, everything on my plot is within +/- 3db. The system sounds great, so is this a "don't fix it if it ain't broke" thing?
    for on the 250 -500hz range can have a howling effect

    I'm not sure I understand this, typo maybe?

    Tad
  • DraDra Posts: 3,777
    He's saying that from 250 to 500 that the speakers are hot (with a major dip at 400).

    Put a pretty wide filter centered around 350 hz. - 3 db. Then add a narrow filter at 400 and boost it 5 or 6db.

    DRA
  • DennisDennis Posts: 801
    Dra wrote:
    Put a pretty wide filter centered around 350 hz. - 3 db. Then add a narrow filter at 400 and boost it 5 or 6db.

    DRA

    With the trend of 250 - 500 needing a minor cut, I am suspicious of the dip at 400. I think it is a cancellation caused by a reflection (perhaps off of the ground since the auto EQ was run outdoors). I think that a 6dB boost at 400 will do much more damage than just ignoring it. I would try auto EQ with some different mic positions and then take note of behaviour at 400...is it the same?....did you move the mic two feet and all of a sudden there is a peak at 400?
    You get the idea.

    The first part of this reply is directed at DRA but the questions at the end are directed at tado921.

    Dennis
  • GadgetGadget Posts: 4,915
    Actually I had written a big long reply and the dog ate it...it's lost in the morass but here's the gist...

    The posts in the FAQ that deal with use of PEQ's to replace Auto eq cuts and boosts were predicated on the 240/260/400 series platforms...the 260 has 18 pre crossover and 24 post crossover parametrics...

    The DRPA/PX has 14 total...NOT enough to make any REAL dent in most speakers response limitations...( the 260 can throw 13 PEQ's on ANY single output)

    With 9 PEQ's per input you can see that you can put a serious amount of parametric power on the inputs and still have a bunch left on the individual outputs...

    So you WOULD be better to just let the Auto EQ do the majority of the equalizations.. I do this every week in my casino gig using the DRPA+.

    Sorry Dra what I meant is that indoor sound causes all manner of sonic anomalies, and one of those is a buildup of 250-500 hz information that can cause a nasally or howling type of sound. This is especially prevalent in live sound situations where there are any number of open mics on stage that pick up loads of crap that builds up and causes a nasally honky sound that when filtered with a PEQ (or a few) can help clarity greatly, especially with a really thick mix...

    Dennis is right EXCEPT that the OP specified outdoor auto EQ, and if it was done with NO hard surfaces any where in the vicinity I don't think that is the issue, but instead a slight anomaly in the speakers response......Dennis, is there a benefit to placing the mic on the ground in this outdoor EQ setup?

    So, The purpose of the PEQ scheme I suggest is to help deal with indoor room anomalies...

    The one @ 60 hz is a fairly narrow PEQ used to treat efficiency bumps in front loaded subs (most that I have seen and used (look the the specs for most of those and see for yourself) usually a cut, 2-6dB with a Q around 5-6. This usually manifests itself as a BOOMY low end...

    The midrange cut is generally needed between 200 and 500 hz, but can encompass multiple frequencies in that range, A broad cut with a Q in the 1.0-2.0 and a very slight cut can bring clarity to a mix, when dealing with monitors a more drastic cut may be needed to clean up stage mixes in small rooms.

    The HF PEQ is used to help restore lost HF response or can also be used to limit HF squeal if the system is too bright ( many full range speakers that use a low efficiency LF speaker and a high efficiency HF speaker and a less than optimum analog crossover are VERY HF heavy) as most low cost 2 way speakers are... especially 2way 15" like Yamaha, Peavey, and most other budget 2 way speakers are...

    With this method, and a 2 way stereo system with fullrange tops and subs, you still have 1 PEQ for the subs and 1 for the tops available...(but STILL no where NEAR enough to tame even a really good speaker...much less a budget offering)

    So that's my story and I'm stickin to it...
    G
  • DennisDennis Posts: 801
    Gadget wrote:
    Dennis is right EXCEPT that the OP specified outdoor auto EQ, and if it was done with NO hard surfaces any where in the vicinity I don't think that is the issue, but instead a slight anomaly in the speakers response......Dennis, is there a benefit to placing the mic on the ground in this outdoor EQ setup?

    As I mentioned, it did cross my mind that this was an outdoor operation and theoretically there should be no reflections. Without being there with the correct test equipment, it is all guess work. My concern is that the anomaly is not EQable at the mic position but way EQable 10 feet away so trying to correct it at the mic position could make a mess. I suppose running a 400Hz tone and seeing if you can boost/cut the level at the mic position with an EQ would give you an answer.

    Placing a mic on the ground for auto EQ would not be accurate if your speaker was pole mounted due to it being too far off axis. If the speaker was placed on the ground as well, the data might be skewed fot auto EQ purposes but I don't know, I'm just guessing here.

    Dennis
  • Dr. JDr. J Posts: 209
    Hey fellas! I guess I will jump in here and comment on a few things. I have done a TON of measuring outdoors (using Smaart of course) & I can say that even outdoors in a grass field (my backyard) at 8 feet out -- you can still get ground bounce cancellation. I have seen it almost everytime and I used to EQ it until I got adventurous with the mic.

    For the Original Poster here: Work with the TOP ONLY and place it up as high as you can in the air (this reduces the ground bounce). Place the mic 3-4 times the diagonal of the box out ONAXIS. It will be somewhere in the 7-9 foot range most likely. I guess it depends on the size of the box. This keeps you out far enough so one driver doesn't dominate over the other.

    Measure there & flatten the box the best you can. Don't worry about 50,63, 80 Hz being boosted on the display screen. Ignore the maxed bands on the extreme low end side and maybe even the high end side like 16kHz.

    After you flatten the box ONAXIS: Move the mic OFF Axis 15 degrees and see what your display shows. DON'T worry about DIPS. Leave the DIPS alone. What you are looking for when moving OFF AXIS is BOOSTS above 0dB. Try it at 30 degrees as well. If there is a OFFAXIS boost then at that frequency you may need to bring it down a bit. YES - there will be a dip on the ONAXIS now but it will be subtle compared to the OFFAX boost. You don't want to goose the top end.

    You could do this several more times if you like BUT I have found that the critical areas are 10,15,30...etc degrees where this flaw will surface. You could then get picky and do it in the vertical plane as well BUT it would be hard with AUTO EQ.

    Once that is set the best you can get it -- lower the tops back down to the position you would place it at a gig. That may be on a couple of subs or on a pole.

    Re-Run the Auto EQ again -- I bet you will see in the lower mid frequencies 200-400Hz DIPS that rear their ugly head. Don't touch the dial yet. Move the mic closer (5-6ft) Do the DIPS stay in the exact same spot or did they SHIFT? Move the mic out to 10-12 feet on axis........ Did they shift again?

    My experience with this is that the dips you see change when you move closer to the TOP box and when you move away from the TOP box are shifting points of ground bounce cancellation in which is NOT EQ-able.

    On the Smaart screen -- as the mic is being moved -- it will look like a title wave in slow motion that diminishes in amplitude as you go up in frequency (like a comb filter) and by the time it gets to 1K -- from there on out it never really changes.

    You could rig up a way to measure your top completely on its back. Lift it up somehow so you allow room for the connectors. This will eliminate as many boundaries as possible. Place mic 8 feet up between horn and mid woofer on axis.... I will have to try that one myself... :D

    Don't get concerned about the sub until you know you have got a good grip on the Top.

    That is my experience and I see it everytime I measure.
  • Dr. JDr. J Posts: 209
    I forgot to say that -- I have also experienced what Gadget is saying as well with the PEQ's. I think we set up in venues that are probably pretty similar most of the time & for whatever reason 60Hz is a frequency where IF playing a sweep tone it ramps waay up. You don't even have to use a sweep tone. Music on a CD player can confirm a rooms resonance pretty easy by sweeping thru the frequencies.

    I have a PEQ @ 60Hz for boomy rooms which is nearly all of them. I use my ear to set the level of cut however & on the kick drum -- I go around 60Hz and use 50Hz or even 70 or 80Hz. It depends on the band. I know 80Hz is the fundamental -- so I try to make use of that as much as I can.

    100Hz is also a interesting place to set a PEQ for indoors. A cut there seems to really clean up the low mid / sub end and make it clearer.

    Before I do any of that -- I make sure the system has been tuned.
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