If you have hearing loss and need to raise or lower the pitch of audiobook voices into ranges you can hear, you can change them with "Audacity's" free app.
First open the book in Audacity and select a small sample for testing and save that or paste as a new track (mute the main track for now).
Then open sample or select sample track then go to effects>change pitch. In the
semitones area type -4.00 or -3.00, etc, to lower and vice-versa to raise the pitch. Apply and play. When you find a good pitch you can apply it to your entire book. *
After each test, click undo or the effects will keep adding to the last.*
Audacity can be complicated at first, so search youtube if you need help. They have lots of how-to and demo videos for all the features and filters.
Audacity...
https://filehippo.com/download_audacity/Also you should install support for MP3 (LAME) and AAC (FFmpeg)...
https://manual.audacityteam.org/man/faq_installing_the_ffmpeg_import_export_library.htmlYou can also set tempo (playback speed) in Audacity but, many audiobook players can adjust that as needed.
*Smart Audiobook Player has tempo settings that don't affect pitch.
Quick playback adjustments of VLC (these settings not available in android version): Pitch Control, can be adjusted instantly during playback... Tools>Effects and Filters>Audio Effects>Advanced.
To lessen
Background noise in TV/Movies: Enable the Equalizer and slightly boost the center 4 bands (or as needed), then Enable the Compressor in the next tab (I kept default setting).
For video you can
search and download subtitles: Go to View>VLsub...Search buy HASH or title.