Is it possible to reset Engineering mode's audio settings? I have a Quantum Muv (Brazilian phone) with android 6.0

When I first got it, its max volume for media was really low, both with earphones and without, so I followed a tutorial to change the settings via engineering mode. It worked well for headphones, but the speakers were still too low. Some time goes by and I try to change the settings again, but now it's like there's no volume 'slider': there's either off (0% volume) or max (all other %es). The settings are all a mess and I'm afraid trying to fix it will just mess everything up again. 

Is it possible to reset engineering mode configurations without a factory reset?
Open engineering mode using the number *#*#3646633#*#*
Then go to hardware testing
Press audio
Then go to loudspeaker mode
Press ring change to media 
Change value 0~255 change to 60.


I.e...., from if you have messed up everything in all the setting  sid, sip, ring, sph and sph2
From level 0 to 6or 14 the value 0~255 should be in increasing order in counts of 12 or 16.
And value 0~160 keep that in 128 default or for increase in volume keep in 135 that's all.

Do this properly and you will get the slider corrected and increase in volume. 
While doing this process play a song from the music player. 

Even I faced the same issue and got it solved after an hour of experimenting with all 4 audio settings
Don't alter engineering mode again.