Stock is good, sound that is in your head, fast rhythm, warm, full bodied sound.
MrWalkman give an alternative to what is already good.
WM1Z, warmer, brighter
Bright, sparkly sound
Warm, tube sound
The neutral is more like balanced rather than flat, colder than warm, darker than bright, but it is still sound pleasing. I rarely played with this signature.
There is an alt dac option, that makes the sound cleaner (removing the intended distortion that makes the walkman sounded similar to vintage amplifier, sounded more like modern DAP. Other than WM1Z, it is recommended to turn this option on, another side effect of this option is the removal of upper mid bump. You know that WM1A and WM1Z has a different kind of brightness, WM1A added a bump on upper mid, specifically on the presence area, while WM1Z extended the treble (brilliance area). When you use the WM1Z sound, it is like getting both the upper mid and extended treble, don't get me wrong, it is still sound pleasing to my eat, just not on the other signature.
There is an option to raise or lower the gain, something that usually different between region, I always keep this option on
There is a V1 option which gave a different tuning but still kept the bluetooth receiver compatibility but worst battery consumption, and V2 which has a better battery optimization than the stock around 20% increment but sacrificing the bluetooth receiver implementation (it may crash a bit)
Easier region switching, to get a better tuning, and 2 additional custom region: J2 and J3. J2 is like J with better presence and brilliance but still tamed and polite, J3 is like all out but still polite. J2 vs J3 is like AKM vs ESS.
Combine all those combinations (pun intended) and you get many different sounds, for example: Bright + V2 + Alt DAC + J = SE 300, Bright + V2 + Alt DAC + J2 = AKM Sound (Better clarity than 4493, but less offending than 4499 EX)