Capturing audio using Arduino Yun-->USB audio card-->MAX9814 opamp

[yamanoorsai]

I am trying to record audio using a MAX9814 amplifier + microphone and a USB audio card + microphone. I connected the microphone as shown in the figure below:



I verified that the microphones work correctly by connecting them to microcontroller based recording circuit. The recording was clear. So I decided to connect it to a USB Audio card which is in turn connected to an Arduino Yun.

I have 3 different USB audio cards. I am using ffmpeg on the linux command prompt to capture audio. The audio is generally muffled and has a lot of static noise with all of the three audio cards. Am I expecting too much from these audio cards? Are they all going to be affected by static noise? Is there a fix to record audio using cheap off-the-shelf records?