Live Sound Engineering
David Kinden - 20th August 08
I’m going talk about my experiences doing live sound. This is mainly aimed at people who are interested in it as a career, or are just starting in the profession.
Getting the Gig
So you’ve seen the flashing lights and need the power of a mixing desk in front of you? The most common question when approaching venues for work will be “what have you done before?”
If you haven’t engineered at a live venue before you may struggle to get a foot in the door. The way I and many others started was to do some unpaid work. Simply ask the manager if you can ‘shadow’ their engineer sometime, or if you’re at a gig you could ask the engineer themselves.
If you’re obviously keen to learn they will most likely say yes. By doing it this way you learn skills from who ever you are watching, and make some useful contacts in the industry. You may even get you hands on the desk if you seem like you know what you’re doing.
Finding Work
If you know some bands let them know you are capable of doing their sound. If you don’t know any you could approach local ones you find on the internet. This might be payment of a few beers to begin with, but if you get a reputation for being good the money can start rolling in.
A good way to get guaranteed work is to promote your own nights. Many venues offer their premises for hire. By finding some good bands and promoting the night you can land yourself the job of engineer. The common career path of a live sound engineer is to start working in small local venues. Here you may get the chance to work for a small to medium sized band and go on tour with them. From this you may be sought after by their record company, their manager or other bigger bands and hit the big time.
Tools of the trade
- Probably the most important thing to have in your pocket is a torch. At some point you will need to see where various cables are going and it’s going to be dark during gigs. If you have a phone with a bright screen you may be able to use this as a torch.
- White electrical tape is useful for labelling things such as channel strips. A fine tipped marker pen can be used to add labels.
- Wire snippers, pliers and screw drivers. Dodgy mic stands may lead to a vocalist constantly having to raise the mic from pointing at the floor. A few turns of a screw driver and the problem can be overcome.
- Ducktape is of course essential for many things, not least in silencing a mouthy drummer.
- Soldering iron for fixing critical breakages and a multi-metre for testing broken cables.
Sound Check
Powering Up
The first thing to do once at a venue is check everything is working. The desk, effects units, playback devices etc should be turned on first, the amplifiers are turned on last. This means there are no nasty clicks and pops coming out of the speakers when things are turned on. At the end of gigs amps should go off first followed by everything else.
By connecting a CD or mp3 player to one of the desks inputs you can test all the speakers are working. Tests on individual monitor sends can confirm all auxiliaries are going where you think they are. By using some music you know well you should be able to assess if there are any problems with the equipment.
Input gain
The input gain is generally always at the top of the channel strip. This is the amount of amplification or “gain” that is applied to the microphone or instrument. By solo-ing the channel and watching the desk meters you can adjust the input gain for the meters to read 0dB for the given signal. For things like snare drums you can get the drummer to hits the snare repeatedly, altering the gain to achieve the correct level. For singers the traditional 1,2,2,1,2,1 will suffice, but bear in mind they will undoubtedly sing louder than they speak in sound check.
E.Q
I generally have a “less is more” approach to equalisation when live engineering. Adjusting mic positions or instrument setting often give better results when shaping the sound.
The amount of control over E.Q depends on the mixing desk. The smallest models may only have three knobs. One for the high frequencies, one for the mid frequencies, and one for low frequencies.
Larger desks often have a ‘swept’ middle E.Q. This gives you two knobs to control mid frequencies. One controls the amount of cut or boost applied, the other selects the frequency off the filter. This is useful for getting clear vocals. By applying a few dBs boost and sweeping the frequency you can find the best spot for a certain vocalist. I often find vocals need to be cut at low frequencies when singers have their mouth very close to the mic.
Busses
The term ‘bus’ is a channel mixed from a number of other channels. Common busses are the Stereo bus, the Auxiliary bus, and the Group bus. On large desks groups can be used to control many signals with one fader. Grouping buttons are generally found next to the channels faders. Here you can send the channel to the stereo mix, or a number of stereo groups. If you are using eight microphones on the drum kit you could send all the channels to groups 1 and 2. It makes it easy to keep the mix of the kit as you like, while being able to alter its overall level with 2 faders.
Auxiliary Bus and Monitors
Mixing desks have a row of knobs called auxiliary sends. These allow you to send a mix of the input channels to an auxiliary bus. The output from the auxiliary channels are sent to monitors or effects units. There are often ‘auxiliary master’ controls, these control the total amount of signal at the aux output. Generally the master aux controls are set to maximum for monitors, the amount of signal sent is done on the channel strips.
Monitor speakers are called a number of things including fold-back, wedges and foot rests. In some cases they have their own power source, otherwise an amp is needed to power them. In decent sized venues there will be four or five monitors scattered around the stage for various musicians. Each of these monitors is feed from a separate auxiliary send. By doing this it is possible to give each musician their own mix of instruments to listen to.
By asking the musicians what they want in sound check you can start giving them what they need to hear. Generally vocalists and guitarists like to hear a lot of themselves, drummers often ask for mainly bass to keep the rhythm section tight.
As things change during a live gig the musicians may want to alter monitor levels. Common sign language between musician and engineer is pointing to the instrument they want to change followed by pointing up or down.
Dreaded Feedback
Probably the worst thing that can go wrong in a live situation is howling feedback. Let’s face it, at some point in every ones career it’s going to happen, you will learn from it, and hopefully banish it from all your gigs. Typically feedback happens when a sound between microphone and speaker gets caught in a loop. The vocal mics are the main offenders for feedback, as their gain levels are higher than instrument mics. There is also normally the shortest path length between vocal mics and monitors. Prevention of feedback means there is a monitor level at which you cannot go above.
If the guitarist is ridiculously loud on stage, the vocalist may keep asking for more vocals in the monitors be able to hear themselves. In a situation like this the best solution is to explain what’s happening and try to get the guitarist to turn down a little. This also means the guitar will be more controllable in the front of house speakers.
Acoustic guitars can cause problems with feedback. The best way to avoid them is by using an electro acoustic with a jack output fed into a DI box. You can buy round rubber inserts to put in the guitars sound-hole. These stop the resonances of the guitar body and sound hole causing feedback. I read about someone using a modified rubber toilet plunger to do this, though I can’t say I’ve tried it myself. Feedback will be less of a problem with players who stand rather than sit, the distance between instrument and monitor is increased.
