OK. You already have a Shure SM58 microphone and cable, right? So you need the stuff between that and the computer.
You may need to resize your browser screen to see some of these pictures. I customize the most used ones for the forum, but some of them are wide screen grabs and will not fit well.
This is most of the purchase.
The thing on the right is a Peavey PV6 sound mixer. It is a full, formal sound mixer and certainly isn't the only mixer that can do these jobs, but it's mine and I like it. You won't be using most of the connections and controls. I will tell you where to leave the controls so they're off or neutralized.
http://www.sweetwater.com/store/detail/PV6
It's not battery powered or USB. You have to plug it in to the wall.
I use the TAPE-Out on the rear to connect to the digitizer. That's actually the wrong cable in the picture. You need a cable with RCA on both ends (attached).
Everything until this point is all classic analog. The Behringer UCA202 converts the analog stereo Left and Right signals into digital USB for the computer.
http://www.sweetwater.com/store/detail/UCA202
Depending on your headphones, you may want a 1/4" to 1/8" stereo adapter. The Peavey mixer will not directly accept earbuds or any headphone with 1/8" stereo plug (most modern headphones).
http://www.amazon.com/Quality-Headphone ... eo+adapter
Notes:
You can use your headphones as test instruments since you can plug them into the mixer, the digitizer and the computer and tell where it's dying if something goes wrong.
This is going to be a good deal bigger than the bicycle grip size digitizers you have been dealing with. The mixer is 8 inches wide by about 9-1/2 inches tall. You'll need to come up with desk area for it.
You will also need to see sound meters. You can do it with the meters on the mixer, but the ones in Audacity are far more informative. Attached 2 is how I shot the test clip. You can undock the meters from the program and make them very much larger than the default.
This is just what works for me. Your mileage may vary etc. I have a mystery hum that requires one of the special filters on my test clip. I live under high tension wires and it's possible the whole property has that problem. If you have an electrically well behaved environment, you won't need that and you should be able to get really close to ACX compliance with minor tweaks in volume.
I sheared off the end half of that clip to get it into Forum size limits, but the very next thing on that track is me shifting my weight and the sound of the floorboards popping. It took me a minute to figure out what was happening since the sound was going up the microphone stand and wasn't clearly audible in the room.
Let us know.
Koz