The Google's official hearing aid app works fantastically well. Latency is fairly low, and you can filter out parts of spectrum. If the phone has a decent micro

The Google's official hearing aid app works fantastically well. Latency is fairly low, and you can filter out parts of spectrum. If the phone has a decent microphone this app gives you super-hearing. https://play.google.com/store/apps/details?id=com.google.android.accessibility.soundamplifier&hl=en_US https://play.google.com/store/apps/details?id=com.google.and...