Operation; Protecting Your Speakers; Startup Procedure; Precautions - Crown I-T4000 Operation Manual

I-Tech Series Power Amplifiers

3 Operation

3.1 Protecting Your Speakers

It's wise to avoid clipping the amplifier signal. Not only does clipping
sound bad, it can damage high-frequency drivers. To prevent clipping,
use IQwic™ software to enable the peak voltage limiter and average
power limiter in your amplifier's built-in DSP. That way, no matter how
strong a signal your mixer produces, the amplifier 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 amplifier into clipping.
Also, avoid sending strong subsonic signals to the amplifier. 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 filter between mixer output and amplifier input (or
between mixer and limiter).
• Use the I-Tech's onboard DSP to set up a highpass filters. This can
be done using the Wizard in the IQwic software.
• Switch in highpass filters at your mixer. Set the filter to as high a fre-
quency 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 filter frequency just below the lowest fundamental frequency of
that channel's instrument.
Operation Manual

3.2 Startup Procedure

Use the following procedure when first turning on your amplifier:
1. Turn down the level of your audio source.
2. Turn on the Power switch. The Power indicator should glow and
the LCD Control Screen should light up.
3. Turn down the amplifier Encoder knobs (Level controls).
4. Turn up the level of your audio source to an optimum level.
5. Turn up the amplifier Encoder knobs (Level controls) until the
desired loudness or power level is achieved.
6. Turn down the level of your audio source to its normal range.
If you ever need to make any wiring or installation changes, don't for-
get to disconnect the power cord.
For help with determining your system's optimum gain structure (sig-
nal levels) please refer to the Crown Amplifier Application Guide,
available online at www.crownaudio.com.

3.3 Precautions

Your amplifier is protected from internal and external faults, but you
should still take the following precautions for optimum performance
and safety:
1. Before use, your amplifier first must be configured for proper
operation, including input and output wiring hookup. Improper
wiring can result in serious operating difficulties. For information
on wiring and configuration, 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 amplifier with the red Clip LEDs constantly
flashing.
7. Do not overdrive the mixer, which will cause clipped signal to be
sent to the amplifier. Such signals will be reproduced with
extreme accuracy, and loudspeaker damage may result.
8. Do not operate the amplifier with less than the rated load imped-
ance. Due to the amplifier's output protection, such a configura-
tion 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 overdriv-
ing other system components.
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