I'm not 100% sure on this, but it's my understanding that...
- The Android infrastructure is setup that, the phone calls are handled by a separated radio processor, and...
- Unless the radio hardware/firmware is setup to provide 2-way voice signals...
- Then all those "call recording" programs can only record the voice through the microphone, which means...
- Your voice will be clear but in most of the cases, the other side will be muffled at best... That's why you see all those recorders have low ratings...
- A few Android phones are properly setup for these, and they even have built-in voice recorder... (
Which Android Phone Has Native Call Recording Function...? - Android Forums)
See this...
Issue 2117 - android - Enhancement: Call Recorder - Project Hosting on Google Code