I hired someone to come over to my place and provide some voiceovers which I recorded on my pc with a microphone that looks like a microphone. I actually had two microphones available, but the Shure 515SB was not producing a good enough quality sound, maybe because it's more suited for capturing live instruments, so I wound up using a mic I had purchased years ago combined with a separate tiny mixer at a Best Buy. Upon recording the voice, we were unable to eliminate this low frequency background noise that appeared upon playback. Could not figure out where it was coming from. What software can I use to edit out that unwanted noise? Thanks.