3.7 A Closer Look at Audio Signal Wiring
Balanced 3-pin female XLR connectors are provided for audio input connection. The audio cables should be wired in one of the following manners:
Fig. 3.11 Audio Input Wiring
We strongly recommend that balanced wiring be used if possible. Some important guidelines follow:
•Always use shielded wire. The higher the density of the shield (the outer conductor), the better. Spiral wrapped shield is not recommended.
•When using unbalanced lines, keep the cables as short as possible. Avoid lengths greater than 10 feet (3 meters).
•Do not run audio input cables together with high-level wiring such as loudspeaker wires or AC cords. (This lessens the chance of hum or noise being induced into the input cables.)
•Do not connect audio and data grounds to- gether. For example, do not connect the audio ground to the Crown Bus ground.
•Turn the entire sound system off before chang- ing any connections. Turn the level controls down before powering the system back up. Crown is not liable for damage incurred when any transducer or component is overdriven.
Balanced phone jacks are provided for “daisy chain” audio output connection. The audio cables should be wired in one of the following manners:
Fig. 3.12 Audio Output Wiring
In order to comply with FCC and EC EMC regulations, it is necessary to add an EMI (electro-magnetic inter- ference) core to the daisy chain cable(s). A core, large enough to snap over both cables, is provided.
IMPORTANT: Do not feed a signal into the phone jacks on the IQ–P.I.P.–DSPor the back panel of the am-
plifier (if provided). The phone jacks are wired in paral- lel with the output of the P.I.P. connector inside the am- plifier. Any audio signal fed into the phone jacks could feed back into the output of the IQ–P.I.P.–DSPand gen- erate a distorted input signal. The phone jacks can be used to “daisy chain” the post-processed signal from the IQ–P.I.P.–DSPto the inputs of other amplifiers.
DO NOT USE THE CHANNEL 2 INPUT if the amplifier is used in either Bridge-Mono or Parallel-Mono mode.
For additional information on audio input connection please refer to the amplifier’s Reference or Owner‘s Manual. It contains helpful information on preventing unwanted subsonic frequencies, radio frequency inter- ference, ground loops, and feedback oscillation.
3.8 When External Power is Needed
The IQ–P.I.P.–DSPdraws 320 mA at +24 VDC and 160 mA at –24 VDC. Many Crown amplifiers can provide this power via the P.I.P. edge connector inside. For these IQ–P.I.P.-DSP/amplifier combinations, no exter- nal power supply is needed. Amplifiers which can sup- ply adequate power include all Com-Techs, all Macro-Tech 5000VZ, all Studio Reference amplifiers and all PIP2-compatible amplifiers. For IQ–P.I.P.-DSPinstallations into 50-Hz versions of Macro-Techamplifi- ers (excluding the Macro-Tech 5000VZ), Crown rec- ommends use of the S4 version of these amplifiers. Please contact Crown Technical Support for more in- formation about power supply options for the 50-Hz Macro-Techversions.
Other Crown P.I.P.-compatible amplifiers may not be able to supply the full 320 mA of +24 VDC power for the IQ–P.I.P.–DSP, depending on how well regulated the AC mains are that feed them and how hard the amplifiers are driven. This includes the Macro-Tech 600, 1200, 2400, 24x6, 3600VZ and 36x12. We sug- gest that a 400 mA +24 VDC supply be added for these amplifiers as a safety measure to be certain that adequate power is available. Note: Actually, external power of only 200 mA is needed for these amplifiers, but a 400 mA supply is recommended to be certain that the external supply, itself, has a safety margin. A mini jack is provided on the P.I.P. panel of the IQ–P.I.P.– DSP for external power connection.
IMPORTANT: The IQ–P.I.P.–DSP cannot be operated from an external power supply if the enable switch of the amplifier is turned off. The amplifier is required to provide –24 VDC.
CAUTION: If external power is needed, use an indi- vidual, isolated power supply for each IQ–P.I.P.–DSP. Do not attempt to share a common power supply with multiple IQ–P.I.P.–DSPmodules or the IQ–P.I.P.–DSPmodules may be damaged.
