Crown Audio I-T9000 HD 3Operation, I-TechHD Series Power Amplifiers, page, Startup Procedure

I-Tech HD Series Power Amplifiers

3Operation

3.1Protecting Your Speakers

It’s wise to avoid clipping the amplifi er signal. Not only does clipping sound bad, it can damage high-frequency drivers. To prevent clipping, use System Architect software’s Level Max suite to enable or display the peak voltage limiter and average power limiter in your amplifi er’s built-in DSP. That way, no matter how strong a signal your mixer produces, the amplifi er output will not clip. Set the limiter threshold so that mixer signals above 0 dB or 0 VU on the mixer meters do not quite drive the amplifi er into clipping.

Also, avoid sending strong subsonic signals to the amplifi er. High- level, low-frequency signals from breath pops or dropped micro- phones can blow out drivers. To prevent subsonic signals, use one of these methods:

•Insert a highpass fi lter between mixer output and amplifi er input (or between mixer and limiter).

•Use the I-Tech’s onboard DSP to set up a highpass fi lters.

•Switch in highpass fi lters at your mixer. Set the fi lter to as high a frequency as possible that does not affect your program. For example, try 35 Hz for music and 75 Hz for speech. On each mixer input channel, set the fi lter frequency just below the lowest fundamental frequency of that channel’s instrument.

3.2 Startup Procedure

When fi rst turning on your amplifi er, follow the procedures in the Quick-Start Guide on page 4 (stereo) or page 5 (bridge-mono).

If you ever need to make any wiring or installation changes, don’t forget to disconnect the power cord.

For help with determining your system’s optimum gain structure (signal levels) please refer to the Crown Amplifier Application Guide, available online at www.crownaudio.com.

3.3 Precautions

Your amplifi er is protected from internal and external faults, but you should still take the following precautions for optimum performance and safety:

1.Before use, your amplifi er fi rst must be confi gured for proper operation, including input and output wiring hookup. Improper wiring can result in serious operating diffi culties. For information on wiring and confi guration, please consult the Setup section of this manual or, for advanced setup techniques, consult Crown’s Amplifier Application Guide available online at www.crownaudio.com.

2.Use care when making connections, selecting signal sources and controlling the output level. The load you save may be your own!

3.Do not short the ground lead of an output cable to the input signal ground. This may form a ground loop and cause oscillations.

4.WARNING: Never connect the output to a power supply, battery or power main. Electrical shock may result.

5.Tampering with the circuitry, or making unauthorized circuit changes may be hazardous and invalidates all agency listings.

6.Do not operate the amplifi er with the red Clip LEDs constantly fl ashing.

7.Do not overdrive the mixer, which will cause clipped signal to be sent to the amplifi er. Such signals will be reproduced with extreme accuracy, and loudspeaker damage may result.

8.Do not operate the amplifi er with less than the rated load impedance. Due to the amplifi er’s output protection, such a confi guration may result in premature clipping and speaker damage.

9.CAUTION – SHOCK HAZARD: Potentially lethal voltages exist at the output connectors when the amplifier is turned on and is passing a signal.

Remember: Crown is not liable for damage that results from overdriving other system components.

Operation Manual page 11