Equipment-Room Rack

| Audio Systems Index |

From top to bottom, the components in the equipment-room rack are as follows:

 
• PowerPorts
  • The two Furman PowerPorts ensure that current of the correct voltage is supplied to the audio components, and they can shut down the entire audio system if the voltage rises too high or falls too low. In such a case, yellow lights will flash, and the Director should be contacted before restarting.
  • Switches in the middle should be always set to "remote."
  • When the first PowerPort is turned on with the key switch, it in turn powers on the various audio, video, and automation systems components in a coordinated sequence with appropriate time delays, as is necessary to prevent loud pops and possible component damage.
  • Another PowerPort is located in the console, and a fourth is used in the Projection Booth for the video projector. There is just one key switch; the first PowerPort turns on the other three during its startup sequence.
  • More on PowerPorts

   

• Video Switcher
  • The Switcher supports eight audio-video inputs, and acts as a mini-mixer between them, sending video signals to the Video Projector.
  • The switcher is operated by either remote, manual, or automated control, as described later.

   

• Fostex RD-8 (ADAT decks, A and B)
  • ADAT decks provide 8 channels each of CD-quality digital audio.
  • A ninth track serves as a cue track for SMPTE time code.
  • The top deck is the A = Source = Playback deck.
  • The lower deck is the B = Record deck.
  • Advantages of digital audio are given above.

   

• Reverb Unit
  • A Lexicon LXP-1 Multi-Effects unit makes the planetarium room sound as small as a bedroom with sound-absorbing surfaces, or as large and full as a concert hall. "Recital Hall" is an excellent setting for most purposes in our room.
  • Audio is sent through the reverb unit with any Auxiliary #1 knob on the mixer.
  • If the reverb unit LED warning light is red, turn down the input at the mixer instead of on the reverb unit. Keep the reverb output at 100%.

   

• Patch Bays
  • The Patch Bays are designed to send any audio source to any audio destination.
  • Click here to see a fuller explanation.

   

• Compressor
  • The MDX-1000 Beringer compressor receives audio signals from the mixer, and limits any peaks that might damage the speakers. Consequently, a more aggressive output to the speakers is possible.
  • The left compressor adds punch especially to the sub-woofer.

   

• Signal Processor
  • The Furman X312-B Stereo 2-Way Balance Crossover signal processor controls the "crossover" point of the planetarium sound system.
  • Audio signals with frequencies above 85 cycles are routed to the five speakers above the dome (front left and right, rear left and right, and dialog).
  • Signals below 85 cycles are sent to the sub-woofer. Since the human voice trails off around 100 cycles, the sub will not transmit unintelligible resonances of vocal signals.

   

• Equalizers
  • The six equalizers control the sound sent to the six speakers, in the following arrangement:

    1 Left Front	2 Right Front
    3 Left Rear	4 Right Rear
    5 Dialog	6 Sub-Woofer

     

  • The equalizers serve as glorified tone control knobs, but instead of just setting bass and treble, there are 4 controls for bass up to treble including every frequency in between.
  • The equalizer settings have been set by electronic tuning of the room and should not be altered.

   

• Amplifiers
  • USA 850 QSC Amplifier (240/8 Ohms) and USA 1300 QSC Amplifier (365/8 Ohms).
  • Sound from the equalizers is raised by the amps to a strong enough signal to send to the speakers.
  • The rack holds one amp per speaker, arranged in the rack in the same correspondence as are the equalizers (see above).

   

• Speakers
  • From the amplifiers, sound signals travel through high-quality 12-guage cable to the five speakers above the dome, and to the sub-woofer in the southeast gallery wall.
  • Speakers are designated as follows:

    #	Abbreviation	Description	Model
    1	LF	Left Front	Tannoy
    2	RF	Right Front	Tannoy
    3	LR	Left Rear	Tannoy
    4	RR	Right Rear	Tannoy
    5	D	Dialog	Tannoy
    6	S	Sub-woofer	Martin Audio

   

• Compact Disk and Cassette
  • Located in console: TC-K615S Sony Cassette Deck and CDP-X202 ES Sony CD Player.
  • Mixer faders 19/20 control the cassette deck, and 20/21 control the CD player.
  • To obtain four-speaker, front and rear left-right stereo pairs, patch 301 to 403 and 302 to 404 (for explanation, see Patch Bay section).

   

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OBU Planetarium:
http://www.okbu.edu/academics/natsci/planet/index.htm