I stated this when the Legend first came out. The threshold tone, even after doing the latest 1.10 update, is still not a functional threshold tone like on other detectors, that changes with ground conditions, or deep targets, etc., but is still just a hum like background noise.
Look at how the threshold tone works on other detectors. It gives you useful information. If they need to work on anything before the release of the 1.11 update, it would be this feature. It sort of works in Goldfield, but still needs a good engineer to get it right. Right now it is still a useless feature on this detector, and I just leave it on zero. I would love to have them fix this, as I've used a threshold tone for the last 45 years.