First of all, huge
apologies for this taking so long for me to get to! There have been some big happenings at work and I kept getting distracted. I know how frustrating dealing with this annoying audio stuff can be (it took a long time to get right and I (used to) do computer tech support for a living!)
I'm watching your video now and I'll type up responses as I go.
No I don't use a microphone from my headset. You could potentially do this IF your headphones has a standard 3.5mm microphone plug, which you should be able to plug in to one of your 1/4" line-in ports (with an adapter). I haven't tried this myself but I would expect it to work.
I noticed that you're using what appears to be a MultiMix 4, which only has two powered XLR ports. That mixer is only capable of powering two condenser mics, which explains why you haven't been able to get power to your third mic. I use a MultiMix 8, which has 4 XLR ports. I actually wish I could use more than 4 microphones, but I need to get a new mixer to do that because I can only use 4 condensers despite the mixer having 8 total lines. I wish I had better news for you about this one but sadly there's no way around it (other than using a non condenser mic, but I don't have any expertise there!)
Also, I do agree that something is odd about the overall sound quality. It doesn't sound like the audio is going through your condenser mics (you bought the same Behringer C-1s that I use, right?) I can rule out some things for you though: Your sound card (or integrated sound card in this case) has nothing to do with it. Because the mixer is USB, it's actually functioning as its own sound card and is therefore completely unrelated to your sound card.
When you listen to your own voices through the headphones plugged directly in to the mixer, does it sound just as poor quality, or is it nice and crystal clear? I'm going to assume that it sounds good there because if it doesn't then something fundamental is wrong and I'll need to think more about that.
So assuming that it sounds good in the headphones, here are my suggestions:
1. Make sure that the correct recording device is set in XSplit. On my computer the mixer shows up as "USB Audio Device" or something super generic like that. If you're lucky your mixer is a little smarter and will show up as Alesis MultiMix 4 or similar. Here's where you set that:
2. Make sure that your broadcast settings have the sound quality set to something good. The defaults in XSplit, at least back when I set it up, were really low. You're going to want 44khz at somewhere around 96kbps. Here's where you set that:
If you don't know how to get to any of those windows let me know and I'll be happy to help.
Finally, I'd like to share a very recent discovery with you that I made that increased my own sound quality by a bit. I only recently realized that for the best sound quality, you want the main output on the mixer to be as loud as possible, and you need to turn down the gain on the mixer's audio device in Windows
to make it not peak like crazy. I set the mixer's level to 10% in Windows. The tricky thing here is that the slider in XSplit controls
the level of the audio device, but not the other way around. Here's a screenshot showing what I'm talking about:
I like to open the Properties dialog you see there, and then use the woefully inaccurate slider in XSplit to get the level to show up as close to 10 as possible. As you can see here, 11 was the best I could do. Then to figure out how to set the mixer settings right, I do this:
1. Crank the Main out ("MAIN VOL") all the way to the max.
2. Adjust the gain on the microphone as high as possible such that the little red "CLIP" light never lights up even when you yell like crazy. I get lincoln to pretty much scream in his seat so I can set this right. Start low and keep raising it until you see the light flickering, then pull it back like 10%.
3. For the "LEVEL" of the microphone, this is just a matter of making it sound good in the stream. Too high and you'll clip which is bad, and too low and it'll be too quiet! This just takes some experimenting with. Best if you get someone with sensitive ears to listen to the stream and tell you what sounds best.
Check those things, let me know if any of them are helpful, and I'd be happy to keep plugging away at figuring out how to make it better! I want to promise that I won't take as long next time, but I'm in LA at E3 June 4-7, and then backpacking June 8-10! I will do my best though