I don't get it!!!
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Posted on Jun 24, 2013 12:41 am
mclir9
www.witchsmark.com
Member Since: Aug 13, 2006
I have always followed the rules with my PA system setting up a Gain Structure using pink noise, so that if worst comes to worst I can save my speakers/amps from blowing. Now because of this my amps are all set to below half, because that's where they began clipping via the Gain Structure process. I have always fought with getting some power out of the system the Subs especially. My band played a festival this weekend in which a professional sound engineer (Frank "The Beast" Beasley) did our sound and used our Subs amp and subs. The first thing he did was crank my Subs amp to 10 and still was laughing at the power coming from my subs, so then he went into the Driverack PA and set the Bass to +20 which finally began producing some respectable lows and sounding freaking outrageous. I was a little worried about my amp and speakers, and upon checking it out it was running smooth as ever, no clipping or nothing going on and frankly we kicked butt. What the hell, I don't get it!!! Is that how it is, play it safe and have a weak *** system, or push it and have a great sounding system?? My system consists of the following:
1 - Allen Heath Mixwizard 16
1 - Driverack PA setup for Triamp'ing
1 - QSC850 running the Highs
1 - EP4000 running the Mids
1 - EP2500 running the Subs
2 - Peavey SP2 for high/mids
2 - Yamaha SW118V for the Subs
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Jun 24, 2013 03:23 am Well, I hate to say this.............. But!................. You're running the gain too hot from your board. If you have the inputs turned down below half on your amps, And you clip if you turn it up. Then the gain is WAY too hot coming out of the board.
In live sound, normally the amp inputs are turned all the way up. This will give you head room to move. By turning the inputs on the amp down, and pushing the board, you run the risk of a square wave. And no matter how many limiters you put on your system, a square wave will clip and kill everything,
Since you have a DBX DriveRack, use that to cut the power to the mids and highs. And leave the inputs to the amps cranked all the way up. For the subs, put a high pass filter at a -24 dB slope, starting at about 30hz. What this will do, is allow the subs to work more in there range, and not let the extreme lows to clip the subs. As most 18" drivers do not produce much below that range. Unless you have them coupled with other boxes to multiply the excursion. However, with only two subs in total, you don't have to worry about that. Remember to set the Low Pass Filter to where the manufacture says. Which should be somewhere around 125hz. With this set up, you should be able to push the low end a great deal before clipping. And remember, never push the 31 band EQ up in the low end. Allow the DBX to do that work. Pushing the low end in the EQ will only serve to create more square waves and lead to early clipping of the amp. And kill your subs.
mclir9www.witchsmark.comMember
Since: Aug 13, 2006
Jun 24, 2013 12:35 pm So your saying to turn the knobs on my QSC850, EP4000 and EP2500 all the way up to 10, and them keep the Driverack Crossover outputs at Unity Gain?? Sorry for my ignorance, just want to make sure I am getting you correctly.
Also: "You're running the gain too hot from your board. If you have the inputs turned down below half on your amps, And you clip if you turn it up. Then the gain is WAY too hot coming out of the board. "
I don't clip when I turn it up, it will only clip when I turn it up if I have my Mixer maxxed all the way to 10, as when you are setting a Gain Structure.
Jun 24, 2013 12:39 pm I don't believe I have ever run a system where the amps were set at anything other than wide open...to control the volume, turn it down at the board...follow Rob's advice, he knows of what he speaks.
mclir9www.witchsmark.comMember
Since: Aug 13, 2006
Jun 24, 2013 03:56 pm How do I know if I am about to blow my speakers? Or clip the amps? Oh, and I forgot to mention my ep2500 and ep4000 are in bridged mode, don't know if that matters.
mclir9www.witchsmark.comMember
Since: Aug 13, 2006
Jun 24, 2013 08:48 pm Ok, got my system back together and cranked the amps up. Did a test run and wow that's alot better. Couple of questions:
1.) Now that I have setup this way, I set individual channels with Gain Trim Pot to Unity/0 on the meter and use the slider for volume after that correct??
2.) What should I do with the Driverack X-Over gains, leave them at 0.0 or is there a way to adjust these too logically.
3.) The Driverack uses the built in 28-band EQ, you talked about " never push the 31 band EQ up in the low end. Allow the DBX to do that work." Do you mean let the DBX's EQ handle that, or even on the DBX EQ turn the lower frequencies down, which right now 40, 50 and 63HZ are all bumped up to +5??
Jun 24, 2013 11:24 pm The DBX you set to taste. So, if you like the sound of everything at unity, that's fine. Normally, the highs are set way lower than the subs. As much as -12 dB from the subs.
The reason for this is that the human ear can pick out the high end much easier then low end. Plus, high end is takes less energy to produce then it takes to create for the subs.
I see that you had everything in bridge mode. I think for your subs, that's fine. I would run the top boxes in stereo. So that it is one channel one box. This will reduce the amount of power going to the high packs, and reduce the chance of damage. Also, it will free up some headroom for you, and allow you to get more gain out of your system.
As far as boosting frequencies goes. The rule of thumb in live audio is to never EVER boost! You can move the gain up on the whole low end spectrum by using the DBX DriveRack. But, using the EQ in the DBX to boost 60hz is not the best idea. As kick drums live at 60hz, you can easily clip the amp and sub by boosting it in either the DBX or the 31 band EQ. Now, on the board strip for the kick or bass channel, it's fine to cut or boost on the parametric EQ. As this will affect the gain of the channel. And you can adjust the gain structure accordingly. With the way I'm instructing you to do your setup, you'll find that you can reduce the amount of gain that is needed for the kick to be out in front.
So try this. On the DBX, run the gain for the subs up about +3 dB. Cut the gain to the tops about -6 dB. You can either cut of boost the high end to taste. Have the subs in bridge mode, and the tops in stereo. Use an "AUX" or a "GROUP" send to drive the subs. This way you can isolate what is going to the subs. No need to have vocals or guitar going to the low end, as they really don't need it.
I think that you will find that your system will have new life. And less danger of things getting damaged.
mclir9www.witchsmark.comMember
Since: Aug 13, 2006
Jun 25, 2013 12:44 pm Awsesome, thanks Rob. Just too make sure about the running the EP4000 to the SP2 in regular Stereo Mode specs are as follows:
EP4000 is Stereo 550W per channel at 8 OHMs
Peavey SP2 - 500 Cont, 1000 Prg and 2000 Peak
The EP4000 is big enough for those speakers in Stereo mode??
Thanks again
P.S. How do I run my subs from an AUX or Group while using the Driverack?? I am currently using both inputs on the driverack Left and Right.
Jun 25, 2013 06:02 pm Well, the EP4000 is a little lite on power for your tops. But, it should be fine for some time. And besides which, the specs given are for switching amps. The 2000 peak is for something like 1/4 cycle of 40hz burst. Or .0706 ms burst of 2000 watts. If you were to run a 1000 watts for more than a few seconds to it, you would start to smell a little of the speaker starting to burn.
I guess this is the long way of saying, "Stick with what you got for now".
As for as the AUX/GROUP goes. I was hoping that you had the model that uses three input across the back. Without the third input, HPF on the channel strip is your friend!
mclir9www.witchsmark.comMember
Since: Aug 13, 2006
Jun 27, 2013 10:04 am Do you think it would be worth purchasing (2) PV112's and throwing those in the mix for the high's instead of letting the horn on the SP2 work the highs?? So I would have (2)Yamaha SW118 for lows, (2) Peavey SP2 for Mids and (2) Peavey PV112 for highs.
Jun 27, 2013 10:10 am Considering the size rig you are running, why do you have mids and highs separate? Seems to me you would save money, complexity and setup time having a simply two way crossover and allowing a single cab to run the mids and highs, with 10"-12" and a horn...letting it's own internal crossover deal with that.
I understand moreso the desire for a three way xover for larger systems due to placement differences and such things, but given the size rig you are running, and presumably the size shows you are running, I think I'd be stickin' with a two way system and carrying less cabs, less amps, and have less complexity to the setup.
What was the original purpose of going the three xover direction in the first place, when there are soooooo many good options for single cab highpaks out there?
mclir9www.witchsmark.comMember
Since: Aug 13, 2006
Jun 27, 2013 12:37 pm Well, I originally went with the 3-way option on the advice from some Tech Reps from DBX. They are the same people who originally told me to do the Gain Structure that made it where I only turned my Amps up less than half way. Considering I am crossing over from Mid to High at 1.8Khz (which is where the SP2 crosses over internally on its own) I guess it doesn't make sense. We play for about 200 - 300 People at any given festival. I'm wondering if I shouldn't simplify and go with what you're saying. Run the Driverack in 2-Way mode instead and just use the EP2500 for the Subs and use the EP4000 for the SP2 but plug into the Full Range instead of the Bi-Amp option on the back, and setup driverack to X-Over at 95Hz. Would this be your idea??
Jun 27, 2013 12:43 pm That is what I would do, and always have in any PA I have run for that type of use...while Rob is the best one to explain, cuz he knows it better and has worked much bigger systems, what I have always done is have a two way xover, one to the subs, one to a wide range high pack...the subs take the biggest load off the highpack, the very, very low lows...so it's woofer (10, 12, 15, whatever) runs much, much more efficiently not having to deal with those...then have amps for the subs rated about double the wattage of the highpacks (cuz the subs will require that much more), all running wide open.
Of all the wattage used in a show, half the power is used for about a tenth of the frequency range. :-)
...and I would stop taking advice from that other dude...I'd trust Rob over all else...
mclir9www.witchsmark.comMember
Since: Aug 13, 2006
Jun 27, 2013 01:24 pm So maybe I should throw the ep4000 on the sw118s, and the ep2500 on the sp2's. Rob, what do you think about all of this?
mclir9www.witchsmark.comMember
Since: Aug 13, 2006
Jun 27, 2013 02:39 pm Deleted By mclir9
Jun 28, 2013 12:11 am Sorry for the delay on getting back to you. I had some stuff to take care of.
Well, are still not getting the sound that you want out of your rig?
If not, well....... Low end takes a ton of power to get it out there. But, you're only running one per side to being with.
I wouldn't over think the whole restructuring of your rig, and get into buying a bunch of gear right now. If the rig fills the rooms that you're working, then let it make money for a bit. Once you start working bigger rooms, then worry about spending some money to increase the size of it, and rearranging your amp rack.
If the band is happy, and the audience to. Then let it ride. Enjoy it paying for itself.
mclir9www.witchsmark.comMember
Since: Aug 13, 2006
Jun 28, 2013 10:09 am Well, if I can free up my Highs AMP (the QSC850) and let the SP2 do its own built in Crossing Over, then I can use that AMP to run another set of monitors which would be very helpful because right now I only can get (2)Independent monitor mixes and the QSC would give me (4) 1 for singer, 1 for Guitar, 1 for KB and 1 for drummer, which would fix my problem from an earlier post about running 3 monitors from one channel at 2OHM. Do you think letting the SP2 doing their own built in crossing over will degrade my current sound of letting the Driverack crossover, i.e. I have the driverack crossing at 1.8Khz and that is where the SP2 crosses on its own anyways??
Jun 28, 2013 10:22 am I like the sounds of that idea a lot...same gear, rearranged, better usage, epic win!
Jun 28, 2013 04:39 pm You will lose a touch on the over all volume of your PA. But, I don't think that it will be all that noticeable. I agree with you that free up an amp to increase the monitor mixes is a good idea.
mclir9www.witchsmark.comMember
Since: Aug 13, 2006
Jun 29, 2013 06:02 pm Being that I have decided to go with the new Gain Structure method of putting the amps to 10, I don't think I will even notice the volume difference except that it will be much louder without having to push the faders as high.
