Crown Audio I-Tech Series operation manual I-TechSeries Power Amplifiers, page

I-Tech Series Power Amplifiers

9 Appendix B: Setting Sensitivity for Best Gain Staging

Optimized system gain structure maximizes signal to noise within the sys- tem. Adjusting your amplifier to fit within an optimized system gain struc- ture is accomplished by properly setting both the sensitivity and attenuation controls within the amplifier. I-Tech amplifiers offer 149 sensi- tivity and gain settings allowing very fine adjustment of the amplifier’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 amplifiers, 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 amplifiers and can, in fact, degrade performance. The attenuation adjustment should only be used for small (3 dB) or tempo- rary adjustments in amplifier gain. Instead, set the sensitivity/gain of your I-Tech amplifier so that you can achieve the desired output with the attenu- ators at or near 0 dB.

Example: Suppose that you are using an I-T8000 with the sensitivity/gain set at 1.4V/37.1 dB. After optimizing the gain structure of the rest of your system you find that attenuating the amplifier 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 amplifier 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 amplifier, you do not find the setting you need, try changing the status of the max input setting and search again.

Operation Manual page 39