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3. Source Setup

The source assembly consists of the excitation loudspeaker, stand, power amplifier and cabling. This equipment is not provided in an IRIS kit and must be supplied by you. Please refer to Source for loudspeaker requirements and the manufacturer’s documentation for your specific source equipment.

IRIS Kit Outputs

  • The Zoom F4 in a Revision 2 IRIS kit provides a balanced line-level output over a male XLR connector.
  • The MOTU 4pre in the original IRIS kit has a balanced line-level output over a female TRS connector.


  1. Place the source in the initial source position.
  2. Setup any necessary equipment to drive the source such as the power amplifier and cables.
  3. The source will be driven from a line-level output of the audio interface. Locate an appropriate cable and connect it to the source end.
  4. Unless you’re sure of the power amplifier configuration (see note below), leave the gain turned down for now.
  5. Do not power on the amplifier yet. This should be the last part of the system to power on to prevent any clicks or pops in the speaker. When packing down, it should be the first thing to power off.


If you are making measurements with a calibrated IRIS system (e.g. to measure sound strength), please ensure you set up the source in exactly the same way as when the system was calibrated:

  • Set the same gain on any amplifiers.
  • Use the same type of cable. For example, if you used balanced (e.g. XLR) cables to connect the source, you must always use balanced cables. An unbalanced cable may reduce the loudspeaker level.

Note that you can adjust the excitation level from within IRIS software without affecting system calibration.