Full Duplex Recording Why you need it? How to get balanced recording level

Most  telephone voice recorders using a simplex recording e.g., they only record one channel.

The analog phone line is a 2 wire line, and therefore, part of your speech signal is reflected back to your telephone earpiece. Most recorders will record the signal from your earpiece counting on the fact that the reflection is there at an appropriate level.  The problem with such an approach is signal level variation,  most of the time the near end  signal ( your voice)  will be much lower than the far signal. This is even worse with VOIP (Voice Over IP)  lines. VOIP lines use echo cancellers to suppress the echo reflection to the earpiece, and therefore, you get great extent of near-end signal level variation.

The Full duplex recording on the  Sparky+ USB Recorder overcomes  the signal variation problem.

How do we get the near and far ends to record at exactly the same level? We record both sides of the conversation, one channel records the earpiece while the other records the mouthpiece. We took it a step further and added a digital volume control which equalizes the mouthpiece recording level.

The result is a perfectly balanced recording.