Saturday, April 15, 2017

Live Sound

Jason A Phillips
April 11, 2017

Live sound mixing is the process of electrically or digitally blending together multiple sound sources at a live event by an audio engineer using a mixing console. One of the most difficult things to achieve is a good monitor mix, but first things first. You must figure out what instruments will be used and how many vocals microphones are going to be needed.

Setting The Stage

Knowing the instrumentation allows you to set the back line (stage) and where you find out whether you need DI's or microphones for amps. Some musicians provide their own DI's and others expect you to provide them. If they play keyboards they will let you know weather they want to run mono or stereo. Many keyboard players play more than one so you could end up running four or more XLR's to accommodate their expectations. If a musician is using an amp they will bring their own. You will then only have to provide a mic and sometimes guitar players will even provide their own. Other instruments you may need a DI for is an acoustic guitar, fiddle, mandolin or a drum pad. The last set of microphones you will need are for drums which could consist of a minimum of one microphone up to more than ten. The last part of setting your stage is putting out monitors or wireless in ear systems. Of course this is based on how many performers you have and how much equipment you have available to use. Typically each performer gets their own monitor, however in smaller venues people may share or go without having a monitor. Also having a group of background vocalist singing around one mic may benefit by using only one monitor.


The first thing you will want to do is set your preamp level/gain. Having this to low or to high can cause problems later in the mixing process. Typically each instrument or vocal channels will not be the same for everything on stage. It is determined by how much volume is being sent into the microphone. An example is the volume of someone's voice is not going to be the same as a kick drum or guitar. For different instruments you will choose different dynamics processing such as a gate or compressor. For mixing live sound most people will always use a gate on drums, however in a studio situation there are other options more suitable than using a gate that are more precise. You will always want your gate to come before the eq and compressor for the drums. Sometimes gates are used for more of an effect than for noise reduction and during that process the gate will be placed at different point in the signal chain. Now weather you put your compressor or eq first in the signal path is your preference and you can achieve different results either way.  Compressors can be very difficult to work with and will make a mix very muffled pretty quickly. Learning how to work these will take time but you will benefit greatly by using them. Equalizers are used to carve out specific frequencies for different instruments. On a kick drum you may want to here 50 Hz or 60 Hz for the low end so you might boost this. On a vocal you will probably cut out 50Hz or 60Hz, especially if you have a female singer. The last part of the signal chain in the channel is the fader output to the master section. This is where you balance all the levels to make each instrument fit together perfectly. This changes frequently while you are setting your compressors and eq's for each channels. Once you have reached a good balance, some effects might be added. Reverbs and delays can make a big difference in the way the music sounds and can be a great benefit to the show. Learning to eq and compress effects can also add a great deal of sound and texture to the mix.  The last part of the mix is to put a compressor on the master. This will help give an overall balance to the mix. Having an eq on the master is used a lot for correcting sound issues for the venue you are at. I try to do very little equalization on the master unless needed for correcting the room. If you continue to find yourself adding or subtracting a lot of frequencies on the master you should go back and revisit the eq's and compressor's on your channels. Nearly every time you can correct the situation there.

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