Scale Logic (Ad-free)
Rated 4.3 out of 5. Was $1.19
When first learning to play a musical instrument, scale key signatures can appear very confusing but Scale Logic helps to illustrate that this is not the case. This unique app gives you an alternative and fresh approach to learning major and minor scales based around the tones and semitones found within a scale.
Protect File Pro
Rated 4.2 out of 5. Was $2.99
Protect File is a useful application to protect your files of all types (photos, videos, audios, pictures, XXX-content, *.doc, *.docx, *.ppt, *.pptx, *.xls, *.pdf, *.gif, *.jpg, *.bmp, *.png, *.mp4, *.avi and other files). To protect a file use crypt algorithm using a password. Protect File is optimized for fast using.
Volume Scheduler Pro
Rated 4.2 out of 5. Was $0.99
Volume Scheduler is very simple app that do not use any background service neither it uses gps, wifi and such other android services to change the profile, you simply need to specify the time you want to change the profile, most of the time you are well aware of your schedule, still some time things are not as per schedule like you get late to office, or at home, so app provide you the snooze/postponed options, so you can postponed applying the silent / loud profile by just single tap.
Thanks OP. Scale Logic looks the goods.