30 Appendix
Amplifi er Application Guide
Q. If I use I-Tech and Macro-Tech
®
to power a stack, do I have to worry about any delay or time alignment?
A. There is a ~1 ms difference between I-Tech and Macro-Tech amplifi ers, as well as any other Crown amplifi er
using the Grounded Bridge
TM
output design. See the next FAQ for more about I-Tech latency.
Q. What is latency, and does I-Tech have a fi xed latency?
A. The latency of a device is the amount of time it takes a signal to travel from the device’s input to its output.
When using the analog inputs, latency has been measured at 1.13ms. The latency of the input/DSP section is
fi xed, and does not change whether using no processing or maximum- available processing.
Latency with an AES/EBU input varies due to buffering of the signal that occurs before it is sent to the input/DSP
stage, and is dependent upon the input AES/EBU data rate as shown below:
AES/EBU SAMPLE RATE SRC DELAY
32 KHz 2.744 ms
44.1 KHz 2.358 ms
48 KHz 2.275 ms
96 KHz 1.807 ms
In addition to these sources of delay through the amplifi er, there is the possibility of some minimal delay due to
the wiring of the AES/EBU signal. The AES/EBU standard 110 cable has a delay of 6ns/meter. In addition, the
I-Tech amplifi er has a delay of ~85ns in its active digital loop-thru. To put this in perspective, a system with 50
meters of cable and sixteen amplifi ers all looped through each other would have a delay at the last amplifi er of
1.575us. This is equivalent to a delay of less than one-quarter inch. This additional source of delay will be incon-
sequential in almost all systems and can be ignored.
Q. I cannot fi nd 26dB gain in the sensitivity menu. Is it available in I-Tech?
A. Yes, many different sensitivities and gains are available depending on the setting of the max input level switch.
Refer to the complete list of all 149 sensitivity / gain settings in the Appendix section of this guide.
To set the I-Tech amp for 26dB gain, change the max input level switch to 20dBu using IQwic or the front panel
display. Upon returning to the sensitivity menu you can set the gain to 26dB.
Q. How do I set the power limiters?
A. Via either the front panel LCD or IQwic software.
Q. Why did you put an LCD on the front?
A.
• To provide real-time diagnostics: thermal headroom, load monitoring, etc.
• To provide much of the IQ Network capabilities without the need to set up a network.
• To make monitoring all this information easy.
Q. Do I have to use the LCD?
A. No. The amplifi er was designed for simple plug-and-play operation, and can be quickly setup as though it were
a traditional amplifi er.
Q. How can I keep unauthorized people from tampering with my settings?
A. Controls can be fully locked out through front panel LCD or through higher levels of security using IQwic soft-
ware.
Q. I don’t know anything about networking. Can I get I-Tech’s networking up and running quickly without reading
a book or taking a class?
A. In IQWic version 7, a network wizard is included under the Setup Menu to assist in the process of setting up
your network. The software looks at your computer and confi gures the address of the amplifi er to be on the same
network. In many cases, this is all that is required to set up your IQ Network.
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