Posted Sep 01, 2009 02:10 PM
A Guide to PA Part 3; Stage Monitoring
This is the next instalment in my guide to PA which aims to explain enough for any guitarist to help their band to get the best live sound they can. It will also help them to understand what the sound engineer should be doing and work with them for their mutual pleasure and enjoyment. If you've read parts one and two you will know I think monitors are pretty important and merit some extra detail.
Why do you need monitors?
You are a musician; you need to hear. You need to know you're tight and the audience are hearing a great sound. You need to know where you are in the song and that the notes and rhythm you are playing are exactly in time and tune with the rest of your band. This is especially true if you improvise. Vocal monitors are very important for amplified bands; the singer needs to know they have great tone and the rest of the band need to hear which part of the song they are in. It's pretty scary realising you have a key change at the end of verse three and you don't know if you're playing verse three or two! The vocals will tell you where you are if you can hear them. Sometimes when you make mistakes you all need to adjust quickly and then you need to know what the other band members are doing. Good stage monitoring means you always know what is going on and dramatically improves your self-confidence.
What Are Monitors?
The classic monitor is the wedge monitor. A 10, 12 or 15 speaker and a horn mounted in a cab with an angled back pointing up at the musician. You'll see them at every concert involving a name band. They may be supplemented by side fill speakers which I will deal with later. There are modern alternatives however; in ear monitors and mini monitors fixed to a mike stand. I'll concentrate on wedge monitors and deal with in ear monitors later.
Technically monitors don't have to have an extended frequency response. The audience shouldn't be able to hear them so they don't have to sound like studio monitors, they have a job to do and if they cut through the mix and give the musicians the information they need they are good enough. Most of the information is in the mid-range so this is what needs to sound good. The top end can be rounded off and the bass needs to be punchy but deep bass will only add to the general mush of onstage sound. Any peaks in the frequency response will lead to acoustic feedback or howlround so you need to avoid this and a flat, neutral sound is best. Many small PA's have wedge speakers and the right sort of flat response and can double as monitors. My band use a Yamaha Stagepas system for vocal monitors.
Amplification for monitors.
You need to think about what you are trying to achieve here. There isn't a must have/ one size solution. The monitors need to be at least loud enough so that you can all hear the singer. If you are using a 30W Combo and the bassist is using a 1-200W rig then you can probably just get away with 100W of amplification if the speakers are reasonably efficient (above 96dB/W say). If you are dealing with multiple monitors for each musician and you want to avoid distortion on the peaks then you could easily use 500W+. As ever lots of power means avoiding distortion but risks damaging your speakers if you get carried away at a gig.
It is a common experience at gigs that the sound is really loud but you can't hear anything. This is because tiny muscles in your middle ear tighten up to protect your hearing in the inner ear. Having the monitors too loud will push the guitarists to turn up starting a volume war ending with everything turned to max and the sound pressure so high that feedback starts and the musician's ears shut down. If you ever reach this stage then you must turn everything down a notch or two and start looking for a better balance. Use extra power for clarity and not just to be louder.
Many wedge monitors have amplifiers built in, these are called active monitors. The advantages are that you can add as many as you want as soon as you can afford them and they are simpler to set up. You can even add extension cabs to most of them. Active monitors can also be adjusted by the individual musician which gives them the possibility of a mix which exactly suits them. This does have a downside though which I will get on to later. If not you will have to use a small PA amp or a slave amp driven by the mixer to power your monitors.
In Ear Monitors
These are little headphones like the ones with your iPod. The most expensive and the best ones are moulded to your ears individually like a hearing aid. They are powered by a small amplifier the size of an mp3 player which may be wired to the mixer or can be wireless. The advantages are fantastic. They cut out all the sound you don't want and you can have an individual mix as none of the sound can be heard by other band members. They cut down all the sound spillage on stage reducing feedback and improving the sonic separation of each instrument, they can also protect your hearing. The disadvantage is that they are expensive and that they cut you off psychologically from the rest of the band and the audience. I use headphones to practice and in the studio, I can't imagine using them on stage, but it is a matter of preference. Many people get a little of both worlds by using just one earpiece. It is up to you really.
You could also look at some of the mini-monitors that clip onto a mic stand if you sing. Because these are closer to you they don't have to be so loud thus cutting down the onstage clutter. They won't be loud enough for the rest of the band to hear though.
Mixing the Monitors.
There are three ways of doing this: give the musicians control of their own monitor, mixing at the main mixing desk or by having a separate engineer create a special stage mix.
Having a separate monitor engineer is the ideal solution. They will set up with a separate mixer at the side of the stage where they can talk to the musicians. They will often be able to give each musician a separate mix and since the audience will not hear the monitors they can often concentrate on only those elements that are needed by the musicians; bass, kick drum and vocals for instance. The most glamorous job is mixing the front of house sound but the most important job is that of the monitor engineer.
The probability though is that you can't afford this sort of thing and you will monitor through the mixing desk. You will need to choose a mixer with plenty of auxiliary sends and when you are buying make sure they are pre-fade sends. A pre fade send is one which is not affected by the main fader, this enables you to adjust the monitor levels and the front of house PA separately. The more sends you have the more individual mixes you can create for different band members. If you have just two sends then try doing one mix for the singer and one for the rest of the band. Post fade sends are almost useless for monitors as the sound will change for the band every time the main mix changes. Whatever you do make sure that you have arranged signals to let the sound engineer know if you want the monitors adjusting.
Letting band members adjust their own mix is usually a recipe for chaos. The problem is spillage. Each will turn their monitor up believing that theirs isn't working. This will drown out the person next to them who turns up, eventually all the monitors are at 12 o'clock and no-one can think never mind play music. Only try this if you are all old and wise and no members of the band produce testosterone.
Side Fill Monitors
These are often created by using PA stacks pointing sideways across the stage. The reason for doing this is because the wedges only create a balanced mix if you stand in one spot. Move around and you've lost your sound. Side fills theoretically allow you to dance around like a boy band and still hear everything that is going on. Usually they are fed with the same signal as the PA. The problem is that they can increase the already high volume on stage to unbearable levels and because they are pointing sideways at the mics they get picked up and sent back round to the mixer creating feedback. My advice: don't use side fills unless you are a dance based act and/or are prepared to turn down a notch or two unless you have a very high level of technical competence.
That's it then. Get the monitoring right and you can work together to make a greater sound than any of you could on your own. Get it wrong and there is no way even the best musicians will sound good.