SETTING UP YOUR PA
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There are loads of things to bear in mind in order to get the best sound coming out of your speakers at a gig. How loud do the audience expect you to be? How low can your bass bins go? Here are a few tips on getting what you want without all the guesswork and blind fiddling of knobs.
1. Setting the Input gain. If you have a mixing desk, the top knob controls your input gain. You need to plug your mic. in and scream down it as loud as you can to see whether you're overloading the input. There's usually some kind of LED indication to give you an idea of when overloading occurs. The same procedure applies to the instruments. You need to set up the loudest signal you are likely to use and adjust the input gain to that. If you have bar graph meters, the loudest signal should produce a display of around 0dB. Most mixer/heads don't have input gain adjustment so if this is the case, don't worry about it. One thing to bear in mind. To get the mixer/amp/speakers working as well as they can the input gain needs to be set up as close to "just right" as possible. Don't be tempted to turn it down too low, thinking "at least it won't distort. The rest of the system will have to work overtime to compensate and you'll increase the noise level and reduce the sound quality.
2. The next thing you need to do is to adjust the channel EQ. A good way if your mixer allows it, is to plug in headphones (no speakers are required at this stage) and try to get a nice sound through them. Listen to how a CD sounds through them and use that as a reference. I normally leave the high and low EQ flat and take out some mid - usually at 500Hz. If you can't select the frequency, then you can still cut the mid but not too much or you'll lose punch. I find feedback is quite common at 500Hz so if you can eliminate that on the channel EQ then that saves resorting to the graphic. Another source of feedback can be the higher frequencies at around 4-5kHz. This can often be sorted by the Hi control on the mic. channel. To eliminate feedback, then, you need to listen to the sound of the feedback, whether its high or middly. You rarely get bass feedback, luckily - this can blow your horns, believe it or not.
3. Guitar EQ is a personal thing. If you DI from a pre-amp you can set up the EQ on a permanent basis which, as with the mic. should never need to be adjusted.
4. If you use backing tracks, these should not need any EQ unless they were mixed by a monkey.
5. I never boost bass in any shape or form. You don't have to. There's a little trick, which I shall come to in a minute! Obviously, again if your backing tracks are horrendous (and I've heard some truly horrific ones) you may need to increase the bass but just try to get it sounding "right" through the headphones.
6. The next things to adjust are the levels of each instrument. I recommend setting the backing track fader at 0dB (or 7 if your mixer uses knobs). Your vocals should be around +3 (8-9 on the knob) and the guitar should be around -3. These settings will only work if you've set the input gain as I've described but either way set the vocals and guitars around the backing track. Its surprising how loud you can have your voice when you've adjusted the channel EQ properly.
7. Once you've carried out the above procedure, you should never have to mess with it again. Of course there's always fine tuning but you should only need to adjust the volume of the mic. or the guitar.
8. The fun bit it setting up the graphic. If you don't have a graphic then I strongly recommend getting one unless you can afford £20,000 speakers. (That's just a rough guess).
9. My bass bins only go as low as 60Hz so there's no mileage in boosting the 63Hz sliders to +15dB. What I actually do is to leave them flat if it's a quiet gig and actually turn them down to -4.5dB for gigs where I need max volume. Most "full-range" speakers are no better in this respect so if you need lots of volume, turn the 63Hz slider down before you turn the master volume up. Amp distortion is a problem, which can be avoided by reducing the low frequencies that take up a lot of the amp's power. You can usually tell if your amp is working too hard so this is one way around that problem.
10. As I mentioned with the mic. channel setting, 500Hz can be quite an overpowering frequency so as a rule I lower this by around 3-6dB. If you turn it up you'll hear just how nasty it sounds and like me you'll probably want to get rid of it. With EQ though, you have to be fairly conservative with your adjustments. Taking all the 500Hz out will make the sound very hollow although it does give the impression of deepening the bass (this is my little trick!).
11. Moving higher up the scale, other frequencies to play with are the 2kHz and 4kHz. The human ear is most sensitive to 2kHz. Therefore you can reduce this frequency to make the mix sound quieter. 4kHz is quite a harsh frequency and I normally reduce this by 3-6dB as a matter of course. Adjusting these two frequencies can often solve the problem when you get asked to "TURN IT DOWN". This reduces the piercing aspect of your sound without losing the BALLS. I usually adjust the 4kHz more than the 2kHz. The higher bands shouldn't really need adjusting. I find the 16kHz slider has no real effect on the sound although it might attract a few dogs. The 8kHz slider can soften your cymbals but if you're already attenuating the 2kHz & 4kHz you don't want to lose the edge to your sound. Very high feedback can occur at around 8kHz but because of the way the frequencies sit on top of one another, by attenuating the 2kHz & 4kHz you reduce the risk of that happening. I find on the louder gigs where I don't turn the 2kHz and 4kHz down so much, I need to reduce the vocal level as those frequencies really push the voice out. The same thing works in reverse.
12. It is well worth reading the specification sheet for your speakers to find out their frequency range so that when you need to be loud, you can tailor the sound to sit well within each speaker/horn/bass bins capabilities. This way you can push the master volume higher without creating distortion which in turn can increase the risk of feedback and ultimately risking serious damage to your amps and speakers.

There you go!

Hope you find it interesting.

All the best, Simon

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