Справочник Пользователя для Crown Audio IT9000 HD

This is a suite consisting of a peak voltage limiter, average power limiter, clip limiter and thermal 
transducer limiter. First you will set the mode to automatic or advanced:

• Automatic mode: The software determines the best settings based on the signal characteristics. 
You can modify only the RMS threshold, Speaker Thermal threshold and time constant.  Everything 
else is set automatically. 
• Advanced mode: You can modify the RMS threshold, Speaker Thermal threshold, time constant, 
Peak threshold and Peak/RMS release. 

Peak Voltage Limiter
This limits the peak voltage output of 4.8 the amplifi er. On: Enables or disables this function.  You’ll 
set the parameters below:

• Threshold: Sets the level, in absolute voltage, which the limiter will allow from the amplifi er. The 
range is from 12 V

pk 

to 255 V

pk. 

• Attack Time: Sets the attack time of the limiter. The attack time is defi ned as the time it takes the 
limiter to attenuate the output signal by 20 dB. The range is from 1 millisecond to 100 milliseconds. 
The Instant setting attack time is instant (0 millisecond). 
• Release Time: Sets the release time of the compressor. The release time is defi ned as the time it 
takes the limiter to increase the output signal by 20 dB. The range is from 10 milliseconds to 10 
seconds. 

Average Power Limiter
This limits the long-term output power of the amplifi er.  You’ll set the parameters below:

• Threshold: Sets the average power level, in watts, which the limiter will allow from the amplifi er 
channel. The range is from 10 watts to 10,000 watts. This level should be set to the connected 
loudspeaker’s long-term power rating. Also you must enter the loudspeaker’s nomi nal impedance. 
• Attack Time: Sets the attack time of the limiter. The attack time is defi ned as the time it takes the 
limiter to attenuate the output signal by 20 dB. The range is from 1 second to 30 seconds. 
• Release Time: Sets the release time of the compressor. The release time is defi ned as the time it 
takes the limiter to increase the output signal by 20 dB. The range is from 1 second to 30 seconds. 

Clip Eliminator: This limiter monitors the clip events and attenuates the input signal to prevent 
amplifi er clipping. The attack and release times are preset to optimum rates. Only one parameter 
controls this limiter. “Enable” enables or disables this limiter.

A lookahead feature prevents overshoot of the limiters. These settings were developed with JBL to 
protect the speakers from overvoltage.

Transducer Thermal Limiting
This limits the long-term output power of the amplifi er to what the loudspeaker load can handle 
without overheating and going into thermal compression. You can set the thermal level at which the 
thermal limiter engages, the thermal response time and thermal voltage. Your loudspeaker 
manufacturer might be able to provide this information. Meters show the amplifi er output level in 
dBFS; and peak, rms, and total gain reduction. 

4.8.12 Front Panel Security
Here you can choose which amplifi er LCD 
screens to lock so they can’t be changed.