The microphone used can make all of the difference, as can a noise-free environment.
HERE is a good one. I use similar. I would go with a mono, but then you will want your narrator within the pickup pattern. (See below). If this is out of the budget, then I'd stop by a guitar shop and discuss mics with the salespeople. They should know about mic'ing single instruments, and singers, and have many such mics available at differing prices. Discuss the cables, as you will likely be using direct connection via 1/8" connector, and not have a phantom power source - hence the need for a powered mic.
Now, it sounds like you have more than one narrator. The capture pattern of the particular mic will make a difference. I use a tight cardioid mono mic, because I am the narrator. If you have more than one narrator, you'll want a much broader pattern. Having a powered condenser mic will likely get a usable signal, without having to boost the signal - adding that noise that you are getting.
Seating your narrators very close to one another will be helpful, as will adding some sound baffling to keep the fans in the computer, etc. from being picked up. Sonofoam is great for this, but one can do similar by just placing some cardboard panels with upholstery foam glued to it, or maybe even blankets. Do NOT wrap the computer's case, but place these between it, and the narrators. Depending on your room, you might even want to hang blankets behind the narrators to cut down on reflected (echos) sounds from a live room.
Now, if you do need to record in Audacity, or similar, and watch the movie, you can just Export/Share the Timeline as a Video-only file. Play that in WMP, or similar, and use Audacity to record. I use Adobe Audition, and it incorporates Video in its GUI, so I just Export/Share and Import that into Audition to be played, while I record.
Your sound chip is probably fine, so long as the level of the signal from the mic is adequate for it. I like to have my narration peaking at about -6dB, so that there is no clipping. I can still boost that slightly in my editing program, if needed.
I have several panels of foamcore with sonofoam on them. One is between me and the computer's case. Two more form a large "V", with me in the center of that "V." This effectively kills all room reflections. I just use a couple of lightstands besides my chair, and use some spring clamps to attach those panels. Blankets would work fine too. Your setup might look a bit odd, should someone drop by, but what you want to do is eliminate any liveliness in the room, block things like those fans, and be sure to turn off the heater/AC and kill any audio sources from the rest of the house.
Thanks Hunt for all the info on sound insulation. I never thought to use blankets around the recording area! I am going to try that.
It was definitely the microphone because when I hooked up my old good USB microphone and recorded in Audacity, the result was loud and clear with no background hiss. The imported test files into PrE8 were just fine, so I think that is route I am going to go. It turns out that watching the clip was not as necessary as I thought because my 7-yr-old son, who has to do most of the overdubs, did better by trying to sync with the SOUND of the original clip listening on headphones rather than WATCHING a muted clip. Now I just have to get the dynamics matched with the other clips (a separate post) and I am good to go.
I did check out the links to the professional microphones you sent me, but those are beyond my scope right now. I have professional musician friend who is going to bring over a couple of his mikes next time he visits and we are going to fool around with them for fun, but right now I am going to stick with my immediate (and free) solution of using the USB mike with Audacity.
One more question--I know that PrE8 does not generally work with USB mikes (it doesn't with mine), why is that? It seems like such an oversight that I imagine there is more to it than simply "Adobe forgot to put it in." Do you have any idea why?
Now, just one word of caution. PrE has trouble with some USB mics. Glad that your older one worked in Audacity. Just wanted to mention that there might be an issue using it in PrE. I'd just keep to Audacity, as you have done.
BTW - that was me replying to your other thread, but I did not realize that the forum had logged me out, until after I posted. When that happens, WAHunt3 shows up with an auto-log-in. Do not know where he came from, or why he gets better treatment from the Adobe fora, than I do, but Adobe seems to like my alter-ego better than they like me.
I did not put things together in that thread, but now I see what you're trying to do. I think that you'll get pretty close with my recs. Remember, be patient and listen carefully to all adjustments. Also, knowing that you have and use Audacity, I'd look to doing work with any freeware VST plug-ins there. Then, you do not have to worry about PrE not working with one. There are some VST's on the Audacity site (SourceForge). If you do add VST's, see THIS PAGE first.
I'm still looking for some of the VST's that I found a few years ago. One, Grunge, IIRC, should help you out. So far, I'm not finding anything but a very expensive set of VST's, and this one was free, or cheap.