Sound System Overview

12/30/2017 Update

Sound System Block Diagram.jpg

The control center of the Sound System is the Sound Mixing Board.  This board collects the various inputs, processes them, and then sends the processed signals to other devices, some of which produce sound, and some of which record or send on to other devices.

Input devices:

  • Microphones (20 mic inputs available). We normally use Shure SM57s for instruments, and SM58s for vocals. There are also condenser mics for the choir and the baptistery.
  • Direct Input boxes (DI boxes) which connect guitars or keyboards to the microphone inputs.
  • The A/V Switcher/Scaler which routes the audio from the selected A/V input device (computer, DVD, etc.).
  • Wireless microphone receivers.
  • Line In (to connect to an external source, such as an iPad, MP3 player, cassette or CD player).


  • MAIN The Left channel feeds the main speakers (bass, short and long horns) in the house. The Right channel feeds the wireless hearing aid transmitter and can be sent to an external recorder.
  • AUX 1 (not currently in use) may be used to send a monitor mix to a wireless in-ear monitor. This is a Pre-fader output (more about this later).
  • AUX 2 is currently used to mix for lead guitar in the Contemporary service. This is a recent addition that does not use the Shure signal processor. It is also Pre-fader.
  • AUX 3  (Choir monitor) is used during the Traditional service to help the choir hear the piano/accompanists, and the worship leader/speaker. It is set up with a switching jack so that a stage monitor can be plugged in for local use. This disconnects the Choir monitor speakers, which are located in the Organ Speaker Chambers on each side of the Choir. This mix can be run as either pre-fader or post-fader, switchable for each channel.
  • AUX 4 (Floor monitor) is used to provide monitors on the stage, via several monitor jacks. This mix also can be run as either pre-fader or post-fader, switchable for each channel.
  • AUX 5 (Instrument monitor) is used to provide sound to the organist and pianist. This allows them to stay with a soloist during a performance. This mix is post-fader.
  • AUX 6 (Record) is used to send an independant mix to the recording device (a computer at present). This mix is post-fader.

Signal Flow:

Each channel starts at the top of the mixer and the signal can be thought of as moving down through each column of controls to get to the fader.


TRIM: This control matches the level of the signal coming in to the mixer. If the signal is too low, turning the trim up will boost the signal.

AUX 1, 2, 3, 4, 5, 6: These controls send a copy of the signal to the associated AUX bus, which we use primarily to provide customized mixes for the monitors.

Equalization section (EQ) (Note - Equalization adjustments are a matter of experience and personal preference. Sometimes EQ adjustments can cause unwanted acoustic feedback).

HIGH: Cuts or boosts the higher frequencies, usually associated with cymbals or sibilant speech sounds.

MID: Cuts or boosts midrange frequencies, typically associated with the sound of one's voice.

MID FREQ: Selects the center of the frequency band upon which the MID control will cut or boost the sound. For example, if  the sound is too muddy, you may be able to make it more understandable by moving the MID FREQ to a higher frequency (~3:00 position) and increasing the MID control. On the other hand, if someone's voice is too harsh, you can make it sound less harsh by either turning down the MID control with the MID FREQ in the ~3:00 position, or by moving the MID FREQ to the ~10:00 position and turning up the MID control (to boost the lower midrange for a more mellow sound).

LOW: Cuts or boosts the bass notes.

OL (red) light: Indicates clipping - turn down the TRIM control (top control of the channel).

PAN: This control adjusts the relative signal between the left (Main speakers) and right (Recording) channels. It is normally left in the 12:00 position, except for special circumstances.

MUTE: This button will prevent the sound on that channel from being heard. We normally only un-mute the channels we are using at the time.

SOLO: Allows the operator to listen to that channel only by using the headphones.

FADER: This is a sliding volume control that is used to increase or decrease the signal to the MAIN control, and also to the AUX sends which are "Post-fader." The Pre-fader AUX busses are not affected by the position of the Fader control .  They will continue to send their signals on to the AUX masters. AUX 1 & 2 are Pre-fader; AUX 5 & 6 are Post-fader, and AUX 3 & 4 are selectable as either Pre-fader or Post-fader.