Xlt mixed mode go,s deeper.It uses both discrimination and all metal together on xlt ac discrimination dc non discrimination mode.I do use it occasionally noisy but if you think your in a good area for deep coins missed i would go over the area in mixed mode,on xlt you will here both but the ac discrimination mode wont gos as deep as the dc so check the depth.Fiquer out how deep your discrination modes gos and if you are hitting atarget deeper than that i would dig a few.Dont know the qxt that well so dont know if it is same as xlt. copy from jb site
The merits of Mixed Mode Audio for deeper coin hunting...
Another Great post by Monte
If you feel you would like to find deeper coins than you do in the motion Discriminate mode, you can simply search in an All Metal mode. I'm sure you have also learned that you can gain better depth of detection in the motion Disc. mode by: using less discrimination, sweeping the coil a little faster, and sweeping directly over the coin target.
By operating in the All Metal mode, locking the toggle trigger forward, you will often get a little better depth of detection AND be able to sweep slower (if you haven't over cranked your SAT spped) which will allow you to cover a site more efficiently. Also, when in the All Metal mode you can often hear a target response if you sweep the coil very close to, but not necessarily directly over, it.
Turning Mixed Mode "ON" simply allows you to hear BOTH the Discriminate channel and the All Metal channel at the same time. When in Mixed Mode you might not necessarily hear quite as much or get quite the depth that you would if you were toggled into the All Metal mode, but you will get a good percentage of that depth of detection.
So, the beauty of searching with MM turned "ON" is that you can sweep the coil slower and it won't be as tiring. Additionally, you can hear targets that you sweep close to, but not directly over, hearing mostly the All Metal audio response. This alerts you to the fact that you have a nearby target and you can scan over it directly and get a Disc. mode response.
Some prefer to enhance some of the audio qualities in both modes of operation. For example, if you turn Tone ID "ON" then the Discriminate response from an accepted target will most generally be a higher pitched sound than what you would get from the All Metal signal. Should you elect to turn VCO Audio "ON", which functions with the All Metal channel, you'll get that unique VCO response AND the Tone ID Disc. response from targets, all at the same time, if searching in the Mixed Mode audio option.
The beauty of this, however, is that IF the target is a good conductor target, such as a silver dime or quarter, the Tone ID Discriminate signal response will over-ride the All Metal response and you'll hear a good Tone ID audio.
Should the target be a poor-conductive hunk of iron, such as a rusty nail or iron bolt, the All Metal mode's VCO audio response will prevail.
I can assure you that it does take a lot of time and patience to adapt to. Some people never do. Others, as I have read on this forum, spoke out rather negatively a year or two ago when I mentioned my used of Mixed Mode with my custom programs, yet they're now proudly announcing their use of it. I guess that just shows that some are slower learners, and/or operation in Mixed Mode audio does require a lot of field time and patience to get comfortable with.
If the XLT didn't have that feature, I might not have an XLT! You will do well to work with it in low-trash settings at first so the amount of "noise" will be minimal.
Happy Hunting, and have patience.
Monte