After much observation, I thought I should write this Do’s and Don'ts article for DJs and performers planning to play on a large scale rig. The following are technical notes. It’s assumed that you can beatmix, find good tunes, understand energy, movement and how to read a crowd. 

Number one thing to learn before performing on a large scale stage is GAIN STRUCTURE!!!

Note. 2db increase/decrease is twice/half the  Watts

              3db increase/decrease  is twice/ half perceived volume

"Ok, first let’s talk about peak gain and RMS gain. Peak gain is the flickering peaks that happen above the meat of the audio, the highest voltage that the waveform will ever reach.

RMS gain is “that said meats” average db value."

Today we are going to be referencing RMS Gain.

1a.Just imagine you have 4x275ml cups.

These represent your input channels. 

Input meters legend

250ml = 0db RMS (Green) 

275ml = +24db RMS (Double red) 

1b.Representing the master bus is a 1 L jug.

1c.hypothetically, we have poured 275ml out of cup 1 and now are slowly mixing 250ml of cup 2, 260ml out of cup 3 and now 245ml from cup 4.

All of a sudden, we are spilling the perfect mixed drink all over the floor. This is our representation of audio distortion. "Normally happening first in the mid range around 400-800hz (as that is where most clashes in frequencies will happen) followed by the bass, normally less noticeable but definitely loses power as the system limits or chokes. "

Basically, treat your input channel gain like a glass of fine wine. Keep a fair amount of glass for the wine to breath, maybe boosting mids for a swirl around the rim to increase the aroma.

IMPORTANT!  

Master meter on DJM series, is Post MIX not Pre

1d.In short.

For the best possible output result keep your input RMS gain at 0db as not to overdrive the Mix bus engine.  

2. talk to the engineer before your set, reset the mixer to 0db, any volume disparity will be fixed by system engineer.

"It is common that the last act is ending on a climax so will be getting excited and leaving the meters reading quite hot."

The worst thing you can do is start your set with 0% head room.

Be calm, and ask your engineer and they will attend to any requirement you may need ie. more foldback etc...

3. Be aware of your space. Don’t play a wide dynamic track before a limited more mono mixed track.. (you can’t hear it from the dj position but the energy shift is very noticeable out front when the sides go missing. Can go from magical to hard box sounding real quick..)

4. Move the sweet spot by adjusting key.  As the sweet spot is mostly where the root bass note frequency physically eventuates, pitch up and bring the sweet spot closer, pitch down and move the sweet spot further back. 

"Sweet spot  from the front of the subs"

80hz = 4.28M or 8.56M

95hz = 3.6M or 7.2M

for further calculations  click here

5. Manage audio fatigue by bringing your mix down in volume by 2db, in a break down and give the crowd a min or two rest before bringing back to unity on the next drop or moment that can be emphasised .. repeat 3-4 times/hour. to make sure the audiences ears and molecules are happy and healthy.