Success for what? if you mean "reception?" then none of those have anything to do with that. The right antenna length for the right frequency, height of antenna and type like "yagi" do far more for "success" of reception than those simple radio adjustments. The DSP level adapt is defined AS: DSPLevelAdapt Controls how fast* the DSP adjusts to varying P25 levels. Lower values correspond to slower rates and higher values correspond to faster rates. Small adjustments (2-4 notches) are recommended.
Default is 64. Wouldn't you want your scanner to adapt FAST? at a higher rate? Mine is set as 254, near the highest. I've had good listening with anything over 100. TOO low like 10 or 15 has not been good for mine. The other settings ADC and DAC simply make the digital signal louder or softer to save your ears when a Phase 2 BLAST comes over. Mine is set at +2 and +2 in the car and default of 0 and -5 at home or lower like -1 and -8 WITH the volume maxed at 30 so I can hear the conventional objects on par with the digital. A Yagi aimed at the nearest tower for P25 simulcast or height of the antennas can't be beat.
IT has 13db of gain and works wonders. I have it sitting facing north/east. It's ONLY for 700/800mhz though. I do get some stronger 400mhz and 155.000mhz signals on it. The other one I have was to experiment with to my southwest where I point it at Chicago and O'hare airport. It's a new cheapo yagi for 400-960mhz. 400-960Mhz 7dBi, SpectrumForce Yagi Base Antenna | Scanner Master
It's only 7db of gain and the difference in getting 800mhz Simulcast was like night and day. The big antenna beat this thing with no problem. But recently I moved the transformer element to the rear of the antenna instead of middle and it works much better to beat simulcast. It gets 400-520mhz very well. I left reviews on scanner master for both. The GAIN of 13db was a must, especially if you're in an apartment and don't have attic or outdoor access. 7db doesn't quite get it