Software →AudioRec Pro - Voice Recorder v5.3.9.10

Note: This audio recorder IS NOT A CALL RECORDER, so it can't record phone conversations.
Functionality:
* WAV - PCM, 3GPP - AMR and MP4 - AAC formats supported
* Audio recording in background (even with display off)
* Start/Pause/Resume/Abort recording options
* Option to append(continue) an existing audio recording (only for WAV files)
* Mono and stereo recording (for devices that supports stereo recording)
* Gain (you can adjust the microphone's volume so it can record louder) - only for WAVE/PCM format
* Supported sample rates: 8 kHz, 11 kHz, 16 kHz, 22 kHz, 32 kHz, 44.1 kHz, 48 kHz
* It can record using the microphone used by the camera (rear mic) for a clearer and louder sound (if your phone has this microphone)
* It is possible to use custom folder for the recordings (even on external SD card)
* Option to auto-upload on cloud services like DropBox or Google Drive
* Each record file can be renamed, shared, set as ringtone, deleted.
* Recordings can be named using the current time as name or you can choose a custom one
* Recording & playback can be controlled using the notification buttons (for android 4.1+)
* Audio recorder can be controlled using home widget and lockScreen widget (for supported devices)
* Playback loop feature
Requirements: Android 4.2+
Home Page -

https://play.google.com/store/apps/details?id=com.audioRec.pro2&hl=en