If your recording theough the EDIROL then you'll need to also playback through the edirol or after recording go back to preferences and set the audio device back to computers onboard sound card. ACID can't use two different sound cards at the same time
Some other things:
1) If you are using a dynamic mic like an SM 57 it needs a LOT of gain from the preamp you need to be using an XLR cable into the XLR port or you will probably bypass the preamps and get a miniscule signal in. Once plugged in a dynamic is probably going to need the input gain/volume turned all the way up.
If you are using a condensor mic make sure phantom power is on and that you are plugged into the XLR port
2) make sure you are recding in mono. Acid often defaults to stereo and if you are only using one mic it will only record to one chanel giving you half a sound.
3) recorded audio is quiet. solo the track and turn it all the way up see if you can hear anything