The Behringer X32 and XAir have an oscilator and RTA (Real Time Analyser) inbuilt. Failing that - you can use the Android App Audio Tools to generate and show the RTA spectrum. You will need a calibrated mic.
- Setup a pink noise oscilator. Run at around 80dB. Use hearing protection.
- Setup a calibrated (RTA) microphone.
- Set the RTA meter on flat, Z or C weighted. Do not use A weighted (which is weighted for human hearing sensitivity).
- Insert a GEQ for the FOH.
- Lift up frequencies that are lacking to get a straight level. Some techs like higher lows, with a roll off on the high.
- Ignore the rolloff lower than 40Hz - the speakers cannot physically handle this efficently and we cannot hear it. Trying to boost these frequencies is a waste of power.
Notes:
- The room acoustics will change when people arrive - so don't go too crazy.
- Cut the Oscilator and watch the decay. The EQ might need tweeking to dampen the echo'ing freq.
Other Ref:
Check out Drew's video on using the X32 Pink Noise and the Built-In RTA to Ring Out Your Room. For the RTA he uses (see 4:00):
- GEQ Defaults Checkbox: Use RTA Source (checked)
- RTA Source Checkbox: Solo Priority (checked)
- Select: SPrio - Solo Priority. So when we solo a channel, the screen shows that is being solo'ed.
- Peak Hold: 2s
- Decay: 8s
- Gain : 30dB
- EQ Overlay:70%