Crown Audio IT9000 HD, I-T5000 HD, I-T12000 HD, I-T9000 HD I-TechHD Series Power Amplifiers, page

I-Tech HD Series Power Amplifiers

9 Appendix B: Setting Sensitivity for Best Gain Staging

Optimized system gain structure maximizes signal to noise within the system. Adjusting your amplifi er to fi t within an optimized system gain structure is accomplished by properly setting both the sensitivity and attenuation controls within the amplifi er. I-Tech amplifi ers offer 149 sensitivity and gain settings allowing very fi ne adjustment of the amplifi er’s gain and voltage sensitivity. The Appendix section of the I-Tech Application guide (online at www. crownaudio.com) provides charts with sensitivity in volts and gain in dB for each sensitivity/gain setting.

With other amplifi ers, it is often necessary to apply attenuation in order to achieve the desired sound pressure level. Large amounts of attenuation are not necessary with I-Tech amplifi ers and can, in fact, degrade performance. The attenuation adjustment should only be used for small (3 dB) or temporary adjustments in amplifi er gain. Instead, set the sensitivity/gain of your I-Tech amplifi er so that you can achieve the desired output with the attenuators at or near 0 dB.

Example: Suppose that you are using an I-T9000HD with the sensitivity/gain set at 1.4V/37.1 dB. After optimizing the gain structure of the rest of your system you fi nd that attenuating the amplifi er by 10 dB produces the desired loudness. The same output level, with improved signal-to-noise ratio and headroom, can be achieved by using 0 dB of attenuation and by setting the amplifi er sensitivity/gain to 5.81V/27.0 dB (37 dB – 10 dB = 27 dB).

Note: as indicated in the online appendix, the list of possible sensitivity settings is different for each position of the max input setting. If, while adjusting sensitivity/gain in your amplifi er, you do not fi nd the setting you need, try changing the status of the max input setting and search again.

Operation Manual page 53