HeHe I have to tell you that I cannot actually really tell you for sure. I should have experimented some with it to hear it more carefully. I was so set on getting my friends Halloween project completed that all I listened to were a bunch of roar sounds that I downloaded off the internet. The downloads came in various formats including WAV and MP3 which had to be converted to the ADPCM format. This conversion is handled via a free tool that you can download from the SparkFun site or the 4D Systems site. I found that when I connected the SOMO module output directly into the LINE IN of my PC's sound system the resulting roar sounds were somewhat more harsh sounding than when played on the PC from the original WAV or MP3 files. When I added a small output transformer (a 1K to 8 ohm impedance style that had a bandwidth of 300 to 20KHz) that was hooked up backwards with the 8 ohm side to the SOMO module the signal to the LINE IN became a lot less harsh sounding. The transformer had the additional advantage of isolating the GND system of the MCU setup from the sound system. It also raised the signal voltage level about 1::10 so the signal to noise ratio at the amplifier was considerably less. If I were to use the module again with post amplifier system I would surely deploy the transformer again.

The module and the microSD board are left soldered to electronics board that I built for my friend so it is not convenient to play with it now.

Mike