HAL Applications

Multiple Purpose School Auditorium Divide using a HAL3s

This is a replacement sound system for a school multipurpose room. There is a stage at one end and a moveable wall to split the room. The opposite end is sometimes a meeting room with its own mic and A/V. Here’s the floor plan of the room, divider and a stage mic input in a floor pocket. The new system eliminates long mic cables and is easier to operate.

The new system requirements:

  1. Though the stage has a mic input in a floor pocket, we need a line-level stage input for a mic mixer or a DJ mixer.
  2. A remote control needs to mount out-of-sight backstage to adjust room levels.
  3. At the opposite end of the room by the screen, we need a mic input, and an input for a laptop’s headphone output.
  4. Connect the output of a Blu-ray/CD player in the A/V cabinet by the screen.
  5. A remote control is needed in the A/V cabinet to adjust room levels.
  6. A switch tells the sound system “WALL OPEN” or “WALL CLOSED.”
  7. When the wall is open, the room volume is controllable from either remote and heard throughout the room.
  8. When the wall is closed, only inputs inside each room are heard and controllable.
  9. A feed from the principal’s office for announcements needs to page all zones when activated.
  10. As required by code, a fire alarm mutes the sound system so alarms are heard.
School auditorium floor

This can be accomplished with:

  • (1) HAL3s Multiprocessor
  • (2) RAD2 mic and line input devices, one on the stage and one on the opposite wall by the screen.
  • (2) DR1 Remotes, one backstage and one on the opposite wall or A/V cabinet by the screen.
  • (1) SPST switch, mounted on or in the A/V cabinet to change the sound system from "wall open" to "wall closed."
  • Optional Windows® PC running Halogen may be used to fine-tune volumes and other settings.

School auditorium with sound system

All of the DSP required for distributed speakers, source tone controls, room equalization, principal paging and ducking, speaker protection and Level control is included in the HAL3s. Each of the two outputs has a limiter to protect the speaker, and each zone is preset with a maximum loudness.

School auditorium sound wiring

The Blu-ray player audio is wired to the Line-Plus inputs on the HAL3s, which mono sum the left and right signals. The RAD2 also mono-sums its RCA inputs.

The annoucement feed from the Principal's office automatically ducks any room audio, allowing the page to be heard, with regular volume resuming in a few seconds after the page is over. It will not matter where room remote volumes are set within each room, so a page will always be heard. Voice Detect is used to trigger the page, so a separate switch does not need to be wired from the office.

This configuration uses Halogen’s Room Combine block. It allows you to think about the sound in one room at a time, rather than having to think about how all the other rooms and remotes behave with each wall change. Paging from the Principal is easily handled within the block.

DR1 remote level controls are at each side of the room, and track each other when the wall is open. When the wall is closed, the DR1 at each side only controls the sources found in the same side. The mic inputs are gain-shared to reduce feedback, and the line signals are mixed in at equal volume. For the occasional need to control individual inputs, web controls are available for a tablet, as shown below.

School iPad source controls