Let me say that I generally hunt in the Coin & Jewelry mode where-in everything below the Discriminate setting is audibly rejected and above response with an audio 'beep.' (There are times I miss that 7-tone audio of the M6, however).
because I often like to know if there are other targets in the area, such as rejected nails and other small iron, I'll hunt in the Relic mode with the trigger-toggle centered, providing that low-audio grunt on rejected stuff, and the high-pitched audio on accepted targets ... all based on the Discriminate setting.
Sometimes, we can get tired of the "noise" when hearing everything and might opt for the "Alternate" Relic model function by toggling the trigger-toggle forward. This will eliminate the Mixed-Mode audio that produces the "grunty" audio from targets below the Discriminate setting ... usually. Thus you only hear the high-pitched audio response from accepted targets. The exception to this is when you want to hear everything that is most likely Iron-based as a low-tone, and everything non-ferrous with a higher pitch. Then you use the "Alt." mode with trigger forward and set the Discrimination at the minimum setting. The result is a 2-tone audio again, with a low-tone for ferrous and high-pitch for non-ferrous. So, even with the toggle forward in an "Alternate" function, the Discriminate level setting is very important. I hunt with this function a lot.
Monte