Part of the reason the CTX 3030 may seem more quiet when running higher Sensitivity levels is due to the faster processor and Smart Coil technology. The smart coil scenerio provides a digital link between the microchip in the coil and the processor in the housing. In addition to reducing ambient noise, the "communication" between the coil and control box is continually updating the operational parameters. Other contributing factors are having a proper Noise Channel and allowing the automatic ground compensation software to keep up with the changes in mineralization. In areas with higher levels of mineralization or uneven ground surfaces, you could experience some ground noise. But in relatively mild "uncluttered" soil, the "inner workings" of the CTX 3030 will neutralize much of what we could encounter with other detectors. JMHO HH Randy