✓ Two modes: microphone recording and phone call recording (to the extent still possible since Android 9)

✓ Very high maximum sound quality: can be set up to record at 48KHz

✓ Wide choice of optimized sound quality settings: from the most efficient to the most detailed

✓ Can record while the app is in the background, you can pretend that you aren't recording anything

✓ Will automatically upload the recorded files to your preferred cloud storage:
++ Google Drive
++ Dropbox
++ FTP

✓ Can offload the recorded files to an SD card

✓ Starts on system reboot, continues recording (if started during the previous run)

✓ Saves space: can be set up to remove the oldest recordings if the total size exceeds a maximum

✓ Can record to the app's private folder or to the common storage

✓ Record by schedule: time of day, days of the week

✓ No intricate procedures to start and stop recording: just open the app and click the appropriate button

✓ No accidental recording or accidental failure to record!

More info here: http://bsr.ag38.ru/ (a free evaluation version of the app can be downloaded there!)

TROUBLESHOOTING:

Problem: BSR records for a few hours in background, then stops.
Solution: Check your phone's power saving settings. Make sure the BSR app is "protected" and is allowed to work in the background indefinitely.

Problem: BSR doesn't start up when I reboot the phone.
Solution: Make sure that you had started the recording before you turned off the phone. Check if BSR can be found in the list of running apps (Developers' Options) after startup (without clicking the BSR icon). Check your phone's settings for "optimizations" that might block apps from running on startup. Try making the BSR app "protected".

Problem: Very bad sound quality even on highest settings
Solution: Make sure that your microphone is not obscured. Check if a leather or plastic casing of the phone obscures any of its microphones. Record a short audio speaking or knocking to different parts of your phone to find out where the most sensitive microphones are located. If the mic is on the bottom, put the phone up side down in the pocket so that the mic sticks out. Try an external microphone. Try a different phone, more expensive phones tend to have better microphones.

Step 1. Download Background Sound Recorder Mod (Paid for free Free purchase) APK file on HappyMod.com.
Step 2. Once it's downloaded, open Downloads, tap on the APK file, and tap Yes when prompted.
Step 3.Background Sound Recorder Mod (Paid for free Free purchase) APK will begin installing on your device. Simple.

Step 1. Download HappyMod APK file on HappyMod.com.
Step 2. Once it's downloaded, open Downloads, tap on the APK file, and tap Yes when prompted.
Step 3.Search Background Sound Recorder Mod, click Download.
Step 4: You can download 100% working mods on HappyMod with one click.