Omni Sound Systems

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Omni Sound Systems: Gear and Protocols / How-to (Please Read)

All those who wish to have amplified audio of speakers, music, theatre or prerecorded audio, please read this page.

There are three (3) discrete sound systems for use within the Omni building, as well as sound system 'accessories' such as: microphones ("mic's"), mic stands, various types of audio cables, and stand-alone small amplifier+speaker cabinet 'combos' (such as a small guitar amp).

A 'Sound System' specifically refers to: An amplifier and speaker system setup. Each of the three systems has different protocols for use to ensure their safe and effective operation. The three are:

Seb's Ballroom Sound System: Loudest & Highest quality, also by far the most sensitive and expensive.

SPAZ's Ballroom Sound System: Very high quality, expensive, built with love by SPAZ.

'TOA'-brand Portable P.A. System: Decent quality, not very expensive.

The first two systems, Seb's and SPAZ's, are large and not removable from the Ballroom, while the third 'TOA' is portable, can be moved anywhere in the building and be used by anyone.

Anyone can use the TOA rig, as long as they put it away properly when they are done.

The SPAZ rig can be used by anyone who is a) specifically trained on it, b) reads and follows the written instructions for 'Ballroom SPAZ Sound System' below.

Seb's system is to be used only by qualified professionals. They must be contacted at least one week in advance, and paid $25 an hour. They are:

Liz & Robb


Ballroom SPAZ Sound System

More information on the ballroom page.

Training Guide

Critical Summary
  • Incorrectly turning the sound system ON or OFF, may damage or destroy sensitive equipment. To safely use the sound system, you must use the correct order for turning all components ON and OFF.
Basic Procedure
Correctly configured rack
  • Turning the system ON
    • In the "Crow's Nest" above the stage, accessible from the ballroom mezzanine, there is a small platform accessible by a ladder built into the wall. Crawl up into this platform to approach the "rack", which consists of (from top to bottom):
      1. Power Conditioner
      2. Crossover
      3. Amplifier (amp) for tops (high-range speakers)
      4. Amplifier (amp) for bass (low-range speakers)
    • Ensure the volume nobs on both amplifiers in the rack are turned all the way down (counter-clockwise) before you do anything else.
      • There are four black nobs, two on each amplifier (the bottom two devices in the rack).
    • Ensure the rack is powered OFF, you can tell it's off if the fans are not spinning in the amplifiers.
    • Verify the rack is plugged in, on the opposite side of the wall, where there is an outlet on the right-hand-side of a ladder mounted on the wall, coming directly up from the stage below.
    • Find the "Mackey" audio mixer (mobile sound board / panel), and the "Guitar Center" bag that contains microphones, cables, and other accessories. They should be on the platform in the Crow's Nest, or securely locked in the room below the Crow's Nest, or in the locked in the "Safe Storage Room" between the Ballroom and La Commune.
    • Go down to the front of the stage, from the ballroom level.
    • There are two long XLR cables that run from the rack in the Crow's Nest down to stage-right, which should be coiled on top of the large stage-right speaker. These are the main output cables that connect to the XLR jacks on the back of the Mackey Mixer.
    • Set up the audio equipment throughout the ballroom to meet the needs of the event. Most importantly, ensure the main fader is all the way down. See more detailed instructions for this below.
    • Once the equipment is all set up, BEFORE YOU TURN ON THE RACK IN THE CROW'S NEST, plug in the mixer and turn it on.
      • If you turn the mixer on while the amps are on, you can severely damage the speakers.
    • See notes below about controlling the mixer
    • Turn the main fader up and ensure there is some sound (either from microphones or a source like a laptop), so that when the amplifiers are turned on, you can hear something.
    • Go up to the Crow's Nest again, approach the rack from the platform, and turn on the Power Conditioner (switch is labeled, it's on the front, which is the top left from your view of the rack).
    • Wait 10-30 seconds for the amplifiers to warm up.
    • Turn up both nobs on the bass amp (bottom in rack) first, all the way up.
    • Prepare to turn the tops amp up (second from bottom in rack), but do not turn the tops more than 120 degrees, meaning do not make them turn the nobs' arrows past horizontal.
      • Do not turn the tops amp all the way up, it is very powerful as-is.
    • Go back down into the ballroom, and check that sound is coming out of the speakers.
      • If you started with the tops amp fairly low, you can go back and increase it a bit to make sure they are just loud enough.
  • Turning the system OFF
    • DO NOT TURN OFF THE MIXER FIRST, though you may turn down the main fader before proceeding.
      • If you turn off the mixer before the amplifiers, you risk severely damaging the speakers.
    • First, go up to the Crow's Nest and turn down the volume nobs (counter-clockwise) on both amplifiers (tops and bass), the bottom two devices of the rack.
    • Once these volume nobs are all the way down, turn off the power conditioner, the top device of the rack, which has a switch on the front site, accessible from the top-left of the rack.
    • Only once the rack is turned off can you turn off the Mixer
    • Once you have packed up the Mackey Mixer, and the Guitar Center bag full of microphones and cables, you can place them back in the Crow's Nest or other secure room, and be sure to lock the door
      • In the Crow's Nest, there is a door that needs to be latched shut that faces the stage.
      • The entrance door to the Crow's Nest should lock automatically after closing it. Check this before you leave.
Mixer Operation

Microphones and other audio devices should be configured in the ballroom in order to meet the specific needs of each particular event or arrangement. There is some subtlety to safely and skillfully operate a mixer or other soundboard to provide good sound quality. Here are some details that should help for a typical operation:

  • The Mackie Mixer, and any other related equipment, should be set up in a station some place near the middle of the room, or perhaps further back toward the East wall, but still in the middle as you face the stage speakers.
    • This is where you can hear volumes and issues so that you can make any necessary audio adjustments.
  • Before you turn the mixer on, turn all the trim and fader nobs down.
  • Using XLR, 1/4", or RCA cables (with the appropriate end for the input device), set up any of the following devices as needed, each in their own channel:
    • Microphones
    • Instruments
    • Laptops or other computers
    • Other audio devices
  • Once you turn the mixer on, two lights should come on.
  • Turn up the trims to 12 o'clock (up) for any relevant channels.
    • There is a green light along the side of the main fader (bottom right-hand corner of mixer), which should give you a reading of what sound you are picking up currently.
      • Stay in the green, never let the audio hit yellow lights.
  • Each channel has its own fader, all beholden to the main fader.
    • These faders are in the bottom row of the mixer panel.
    • Never turn a fader up past "unity", the marked position just below the top fader position
  • Leave the main fader up, with some audio reading (ambient noise or music from a laptop) before you go upstairs to turn the amplifiers on. You want to be able to hear something when you turn the amplifiers on.
  • If the audio indicator on the mixer hits yellow lights, but the sound is still not loud enough, you need to go upstairs to the rack in the Crow's Nest and turn the amplifiers up a bit more.

Remember, do not turn off the mixer until you go upstairs and first turn down the amplifiers and then turn the amplifiers off, as instructed above.

Secondary Sound System

Ideally, there should be a simplified, Do-It-Yourself (DIY) style sound system available to set up for lo-fi or low-key events.

Disco room