Your audio mix at a performance usually doesn’t need to be loud to sound full.
Keep in mind that the human ear does not have a flat frequency response across the frequency or volume spectrum.
Your ear hears best at a frequency level between 1 and 4 kHz, especially at volumes below 80 dB SPL.
Elevated Sounds in this range will seem louder than elevated frequency levels below 1 kHz or above 4KHz.
This means that mixes created at identical signal levels (readings on the output meter) sound louder or softer depending on the frequency balance across the audible spectrum.
Low frequencies, below about 150 Hz, tend to round out the sound – they help the sound operator create a full-sounding mix.
A mix with clean highs above 7 or 8 KHZ and warm lows below about 150 kHZ typically sounds good at reasonable levels – full, without being loud.