Boosting Field Recorded Audio

I was out at 4 am a few weeks back recording coyotes in the outback here in Arizona.  The recording on my Edirol R09 at 24-bit/48-kHz was good, but the recording level was very low at -39dB.  I couldn't get the volume level anywhere near my target of -12dB in my DAW, so in order to boost the signal boosted I went with a hardware solution.

So I ran a line-out from the Edirol R09 to a Rolls Promatch MB15b, which converts consumer stereo level signals to professional line level signals and provide audio amplification.  Then to further amplify the signal, the output from Rolls Promatch was directed to a Behringer U-PHORIA UM2 2x2 USB Audio Interface.  The UM2 has a preamplifier and dedicated output level control.

The output of the UM2 was send via USB to my computer and imported using Magix's Audio & Music Laboratory.  I was able to achieve the volume increase, but I was somewhat disappointed in the signal-to-noise ratio.  However, the next step will be to filter out the noise and then work to create sound-design with the coyote yelps.