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The CCRMA Classroom (Knoll 317) is our main performance space.

At 7.5m X 16.7m (25 x 55 feet) it is the largest room in the building.

(XXX need photo)

Read all about the room and its sound system: Bringing the GRAIL to the CCRMA Stage (Fernando Lopez-Lezcano and Christopher Jette, LAC 2019).


In this room you should see:

Audio System(s)

The stage houses a 56.8 channel loudspeaker system with 56 individual loudspeakers and 8 subwoofers numbered in groups:

Note that the main speakers (1-8), subwoofers (57-64), and ground-level speakers (49-56) are located in rolling towers (a.k.a. “stack”). Each has a home position (with tape on the floor marking where the tower corners belong) for the calibrated Ambisonics dome, but can also be wheeled and rotated within a large radius as needed for other activities.

Don’t touch

Stage users are expected to leave all of the following alone:

If you see any problems with any of the above please contact CCRMA staff.

To reset

Using Your Own Laptop

Laptop Audio

Easy stereo: Headphone jack to LTI-1 to DM1000 mic inputs 1+2.

Flexible: MOTU USB to OpenMixer

Laptop Video

Plug in HDMI to one of many numbered ports. Choose that HDMI as the source for the desired projector(s).


“Front”: Epson Pro L1300U

“Side”: Optoma UHZ65

Partial instructions for toggling the front projector between the two possible screens:

    lens position
        load memory
        load memory

Video Routing

It’s a bit complicated to be able to do everything we want.

The video signals to the two projectors are determined by the Kramer VS62HA (manufacturer’s page) 6x2 video switching matrix. The Kramer’s 6 inputs are the 6 possible video sources:

  1. The long HDMI cable normally coiled up on the side of the rack that holds the mixer.
  2. An HDMI female jack on the front of the rack that holds the mixer, labeled “INPUT 2”, often holding an HDMI cable coming from the Atem video switcher (allowing us to project from video cameras)
  3. An HDMI female jack on the front of the rack that holds the mixer, labeled “INPUT 3”, often holding an HDMI cable coming from the HDMI splitter on the output of the KVM switch on the desktop cart.
  4. A VGA (!!) female jack on the front of the rack that holds the mixer, labeled “INPUT 4”
  5. An HDMI cable on the “droid” cart
  6. Apple TV

The Kramer’s two outputs are the two projectors:

But it’s more complicated because we also want anything going to either projector also to be mirrored into an input of the Atem video switcher (e.g., so a concert live stream can switch to a direct full screen display of the material being video projected), and since we’re running HDMI between the mixer cart (that holds the Kramer) and the video cart, we might as well use that same cable to carry digitally the stereo audio that will go out on the live stream.

Kramer out 1 goes into an OREI UHDS-102 (18G) HDMI splitter. Output 1 of that goes to the “wall” projector; Output 2 goes to a Sescom SESAI1001 Audio Inserter, which inserts the analog stereo sound mix from the Zoom H6 as the audio to accompany the video signal on the HDMI cable. But this HDMI signal is somehow incompatible with the Atem (perhaps in terms of resolution or color space), so we use an OREI HDS-102 (less than 18G) splitter, not for HDMI splitting (with only one output plugged in), but as a converter that somehow makes the HDMI signal palatable to the Atem.

Kramer out 2 is the same but without the audio inserter: It goes into another UHDS-102 (18G) HDMI splitter, whose first output goes to the “window” projector and whose second output goes to another OREI HDS-102 (less than 18G) used as an Atem-compatibility converter and not for splitting.

Linux Machine

A CCRMA Linux Workstation is accessible from its own rolling desk.


Beware that Linux doesn’t always successfully talk to the MOTU the first time you try so you might need to “play” or “start audio” a few times.

Also beware that by default the operating system will often perform an automatic 7.1 surround mix that you probably don’t want.

The best way for Linux software to access multiple audio channels is JACK, avoiding these and other problems. (JACK may not start the first time, but after it does start, all other software going through JACK can connect reliably to the MOTU.)

Linux video can’t go to projectors.


The Stage has a disklavier player piano.

HOWTO Play Video

  1. Turn on the appropriate projector(s)

    1. Remotes are in the cookie jar on the desk with the mixing board

    2. [TODO add photo of projector remotes]

  2. Plug laptop into HDMI input

    1. There are 5 inputs:

      • HDMI 5 is in R2D2
  1. [TODO add photo of hdmi input cable + hook mount]
  1. Select the video input for the projector you want to use

    1. [TODO add photo of projector selection matrix]

HOWTO Play Audio

  1. Plug aux into the DI box [TODO add photo of DI box]

  2. Move faders 1-2 up on the Yamaha mixer to desired level [TODO add photo of yamaha mixer]

You can route each channel 1-2 to any combination of speakers


2 USB MOTUs on r2d2

This page of CCRMA documentation last committed on Mon Jan 9 12:34:29 2023 -0800 by Matthew James Wright.

This page was built with uncommitted changes on Thu Feb 2 17:01:52 PST 2023 by matt