Android 9.0 removes the dolby audio control panel and replaces it with what they call smart audio. The control panel in 8 allows you to set a custom frequency range. I have a slight hearing problem in the voice range. I had 9 on another phone and started missing calls (low ringer volume) and the ones I got had low volume. There is no way to set volumes as loud or tweeking frequencies as 8 had. Setting to max volume is useless (doesn't work and the phone contined to reduce volume on it's own). This is a major issue. There are plenty of others but I don't want to write a novel.