Is there any good reason why anybody would NOT leave DT mode turned on?
Well, I personally don’t like the way DT changes the audio tone quality. To my ears, it’s a very unappealing hybrid of the goldfield’s pitch tone VCO style audio and standard tones - I don’t ever use goldfield audio for a reason! Sure, lower DT settings mitigate that somewhat, but it also dampens any real benefits the setting might be providing. With that said, I personally have just been using DT as a “checker” when I get over a borderline, iffy target to see if I can squeeze a little extra target info out of a signal.
To be honest, I still don’t have any real understanding about what actually gets adjusted, filtered, and/or added when I “turn on” or adjust the level of DT. Again, this is all we have to go on about DT from Nokta: “This feature allows non-ferrous deep targets, which are masked or detected as iron (ferrous), to be detected as non-ferrous.” Among other things, I don’t understand how this feature achieves that goal differently than, say, Iron Filter or Stability.
All detector settings involve a give and take - I’m sure DT is no different, but I don’t know where those trade offs are. I believe I have an excellent understanding of settings such as recovery speed, sensitivity, iron filter - I know what I gain and what I sacrifice when I use them, and I am confident in knowing when to adjust them and how much. I don’t have that understanding with DT, so I do not want it constantly running. I fly airplanes for a living…pilots have a strong aversion to flipping switches without fully understanding what the switch does and what the advantages and disadvantages entail!