How many times do you wish that you have recorded a conversation ? Maybe you forgot something important that someone told you, or you want to confront someone with something he told you on another occasion. There are many cases when you wish you have recorded it.
I’ve tested many apps for voice recording and one of the best is Smart Voice Recorder. It is available for free in Google Play Store. It is very easy to use, can run in background and the quality of the voice is very good. The recording is great even if the phone is in the pocket, covered in fabric, so you don’t need to keep the phone in the hand to register. 
This app may also turn your Android smartphone into a spy tool. Today there are so many applications that you can use on your smartphone to find hidden cameras or mics, record sounds that you might not hear naturally, etc.
Please be aware that many states restricte making audio recordings.
In Illinois you must obtain the explicit consent of all parties involved. Otherwise it is felony offense that could result in a jail sentence.