Crown Audio 133472-1A manual System Levels, Amplifier Level

22 Chapter 1: Crown Amplifiers In-Depth

1.6.1 System Levels

When setting system gain, start at the front of the system and work your way toward the amplifi er. A system with the lowest noise fl oor and maximum overall gain will have most of its gain early in the signal chain.

Start out by setting your mixer’s individual channels to 0 dB. The individual channels will vary somewhat from this in the course of setting the mix, but it is a good target position. Also, if your mixer has a +4/–10 dB switch on the output, set it to the +4 dB position.

Next, if your mixer has input trim controls for the mic channels, set them for the highest possible gain (but short of clipping) by having someone speak or sing into the mic while monitoring the mixer’s metering.

Set up your mix for the balance of signals as you want them, keeping the input faders somewhere around the 0 dB point. If necessary, turn down the trim on a channel if you’re not able to keep the fader near the 0 dB point.

After the mix is set, adjust the master levels on the mixer to 0 dB. Any signal processing equipment should generally be set to 0 dB as well, with some exceptions (refer to each component’s documentation for details).

1.6.2 Amplifier Level

Before you can know how to set your amps level controls, you need to understand how they work. Amplifi er level controls are typically not “gain” controls. They do not control the amount of gain the amplifi er produces. You may be tempted to immediately turn your amps level control all the way up (after all, you do want all the Crown power you can get, don’t you?). While that approach could work sometimes, usually it will yield more noise and less overall system gain than would otherwise be possible.

Power amplifi ers are designed to produce a set amount of gain. The function of the level control knob typically is to adjust the signal level coming into the amplifi er’s input stage. Where to set the level controls on the amp depends on the system and how much gain you have available prior to the amplifi er. With the level controls turned down the ampli-

fier can still reach full rated output power, it just takes more drive level from your mixer to achieve it.

First, check to make sure your mixer or console is being operated at optimum signal-to -noise, without clipping the output. Then—with your amplifier’s input sensitivity set to the 26 dB position (if equipped)—turn up your amp’s level controls until you achieve the desired level (loudness). If you turn the level controls all the way up, and it’s still not loud enough, turn the amplifier level controls all the way down (counter-clockwise). Then, change the sensitivity switch to the 1.4V position (if equipped). This will increase the gain of the amplifi er. Now carefully turn the amplifi er level controls up (clockwise) to the desired level (loudness). If its still not loud enough, and your amplifi er has a 0.775V sen- sitivity setting, turn the amplifier level controls all the way down (counter-clockwise), then change the sensitivity switch to the 0.775V position. Take care when you are adjusting the level controls at this input sensitivity setting. Increasing the input sensitivity of the amplifi er may cause the input stage of the amp to overload, so be prepared to back down the output of the mixer by 1 or 2 dB if you notice the amplifier’s warning indicators beginning to fl ash.

Note: depending upon your model of Crown amplifi er, sensitivity settings are internal and NOT user-selectable. Internal sensitivity settings may only be adjusted by qualifi ed service personnel. Refer to your amplifi er’s Operation Manual for specifi cs about sensi- tivity settings on your amplifi er.

Amplifier Application Guide