Live Sound Processing

The following processing is applied to sound routed to speakers and monitors at a concert. This processing isn't applied in the recorded audio (which is audio as it came out of the microphone preamps).

Vocal EQ

This is a work in progress. Currently the vocal EQ is a hump in the midrange.

Vocal Compression

All vocal solo mics have compressors on them. The purpose of compressors is to avoid excessive SPL from loud vocalists in the audience.

The compressors are only really doing anything for the louder soloists: Elizabeth, Brittany and Noshi.

Instrument Microphone Gates

All instrument microphones have gates on them. The purpose of gates is to keep the noise (specifically, hissing) down when the room is quiet, such as between songs after audience stops applauding.

The gate settings are a work in progress. Oleg's understanding is they are applied in absolute fashion, meaning a gate set at e.g. -50 dB always triggers at that sound level, meaning in turn that mic preamp gain affects whether the gate is set sensibly. A consistent mic preamp gain system (see SoundIdeas#MicrophonePreampGainLevels) needs to be implemented before gates can be consistently set.

Vocal solo mics do not have gates because they are muted and unmuted based on whether each microphone is being used, thus a gate is unnecessary. There are also relatively few vocal solo mics (3 out of 32 total inputs).

Choir mics (KSM141's) have gates on them but because these microphones pick up almost as much orchestra as they do choir, they are almost always "on" due to bleed from the orchestra/soloists.

Microphone HPF

All microphones generally have a high pass filter on them to fight feedback. The threshold is set lower for instruments that can play low notes (e.g. cello, viola).

Speaker HPF

Speakers have a high pass filter in addition to microphone HPFs, for good measure.

Speaker EQ

After resonant frequencies of the house are identified, EQ is applied to main outputs to dip the frequency response at the resonant peaks.