Actually I have many questions here. I'm quite new to live signs reinforcement and I have no formal training in it and I want to learn more so pardon me if anything sounds stupid.

We've recently moved in to a new church and I volunteered to be a sound man. Now we have a Presonus StudioLive 24.4.2 console (not the AI) running direct to 3 different power amps that drive a pair of subwoofers (which are connected to an aux set to post-fader and have the 200Hz and above cut hard through its parametric eq acting like a lpf), pair of loudspeakers from the main outs and 2 wedges monitors (connected on other pair of aux). We also have a behringer crossover which the current guy don't know how to use so it's not connected to the system right now. I've noticed that the sound that comes out of the PA system is very different than listening to my headphones (superlux hd681 evo). It's very muddy and lacks very much on the highs. Now the presonus mixer have a parametric EQ for the mains out and a GEQ as well. Questions are :

  • is it a great idea to tune the system by referencing through headphones or should I better use an RTA mic (which I can't afford right now)?
  • should I use the parametric EQ for tuning then GEQ for ringing out feedback?

Thanks in advance and I might bring out a couple more questions. Later if I find the answer here.

  • 3
    Your audience is listening the PA, not an headphone, so you have to setup your system so that the PA sounds OK. As you don't have an analyzer, do it by hear for the time being. The crossover should probably be used to receive the mixing desk main output and split it between low that you send to the subwoofers and high that you send to the main loudspeakers. Use an aux to feed the wedges. Don't hesitate to cut low and high freqs on the wedges. Listen for freqs that 'ring' in the church thru PA and use narrow filters to remove them. – audionuma Aug 23 '15 at 20:11
  • Audionuma is corrrect. I'm assuming audionuma is telling you to use the GEQ to ring out your room. Depending on the firmware version of your 24.4.2, you may also be able to use the SMAART Room Analysis Wizard to ring our your room. You'd need a laptop connected with Universal Control installed and also an RTA mic however. The wizard will use the parametric EQ on the main channels. – Winston Chow Aug 25 '15 at 23:48

First things first, use your crossover. You should connect your main outputs to it and feed your main loudspeakers and your subwoofers power amps from it. Connecting and learning how to configure your crossover should be easy enough and straightforward, after you do some reading of the manual. This will give you the advantage of using less faders to control the total volume and you can set the main/sub balance from the power amps gain control. Then you will also be able to tune your system more efficiently using your main out parametric or graphic equalizer, since the changes you make there apply to your whole system, excluding the wedges. And probably the acoustics of your new church will demand tuning on the frequencies below 200Hz. If your crossover allows it (extra pairs of output), I'd recommend feeding your wedges from the same output you feed the main loudspeakers, which will give more controlled low frequencies. If that's not the case or if your monitors need drastically different equalizing from your mains, use the same post-fader technique to remove the same frequencies that you set you crossover to remove from the main speakers and apply further equalizing, according to their special needs.

Then, as @audionuma suggested, don't use your headphones for the tuning of the system, use the system that needs to be tuned. Use your ears and move around the place to check the sound, since it changes a lot from place to place, depending on the placement of the speakers and the acoustics of the church.

Now, which kind of EQ you choose to use depends on the needs of the tuning. GEQ should be enough for the most of tuning and getting rid of ringing/feedback. Parametric EQ has less bands, but allows you to shape the filters response with much more options, so you could use it for example to boost the highs all together, instead of boosting all the bands of high frequencies of your GEQ. Also depending on the kind of music/sounds that your system is going to be used for, you should apply a low cut, say at 60Hz, since probably you are never going to need these frequencies for any reason. If for example the system is going to be used only for a choir, you can apply the low cut at 80Hz, or a little higher (again, listen to it), and with this you are going to get rid of a lot unnecessary rumble and your power amps are going to work more efficiently, since these frequencies are power demanding. For music with heavy bass and a lot low end information, the filter should be set at 40hz.

Try before applying drastic equalizing to experiment with the placement of speakers and, if any, your microphones. A lot of problems can be avoided this way and it will allow you to use your EQs mostly for enhancing the quality of the sound, rather that fixing problems.

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