Well Johnny dude boi, an M-box 2 is not a compressor. It's an analog to digital audio interface capable of printing 4 simultaneous tracks into ProTools or any other software.

You can plug any mixer you want into its 2 analog microphone, line level devices or directly injected instrument inputs. It doesn't matter if you're mixer is 2 channels or 200 channels. You're only going to be able to record 2 simultaneous analog inputs or 4 simultaneous inputs by utilizing an additional 2 Channel analog to digital converter with SPDIF digital outputs to the boxes digital inputs. That means that you could record from 200 microphones into your 200 input mixer provided you mix them altogether into 2 output channels. Sorry that's how it works.

It would have been better if you had spent money or asked your mom and dad for a book or DVD on basic recording, before purchasing equipment you didn't know anything about. ProTools is only a standard for people to know how to utilize it. Even magazines are a good source of information available at your local music store. But I am assuming this may have been a present? It's an awful nice present. But yeah, recording drums, the whole band, can be quite problematic with only 2 microphones or 2 inputs. But a mixer is only going to complicate your situation. How's that? Simple. You're still only going to be able to record 2 channels at a time. Now that's not really a problem for somebody like myself who specializes in live, fly by the seat of your pants, live mix for stereo broadcast. Yup, live to 2 track. So once you've recorded and/or broadcast that. That's it. Eched in stone. Fin. Unchangeable. So you are in a pickle now. How are you going to record 8 or more tracks simultaneously, so that you can keep instruments separated? You can't. Not possible into ProTools even with a mixer with your current box. You'll have to get a multichannel audio interface. Then you'll discover, it won't record into ProTools. So, it'll probably come bundled with some other software such as Cubase or Sonar, etc.. You'll record 8 to 10 tracks with your other software. After your basic tracking, you'll be able to import everything into ProTools, if you should so desire and then overdub with 2 tracks at a time available with your M-Box 2, into ProTools. So, no mixer necessary.

If you really wanted a mixer with multitrack recording capabilities, a FireWire enabled mixer such as a Mackie Onyx, Phonics & others, would have allowed you up to 16 simultaneous record tracks through anybody else's software, except ProTools. Of course it's a little more money at around $1800 for a 1640 Mackie with included, easy to use software. Better luck next Christmas.

An inexpensive SPDIF analog to digital converter or broken DAT recorder used for the additional 2 inputs to the M-box 2, will allow you to record 4 simultaneous channels into your ProTools. Old DAT machines with blown heads will cost you anywhere from cheap to free. It's OK if it's only 16-bit. That's good for 96 DB of internal dynamic range & processing and you won't need any more than that. I never need any more than that. 24-bit & 32-bit float is highly overrated. If you can't make good recording within a 96 DB, 16-bit range, you can't make a good recording.

Any more questions? Right, SM57's.
Ms. Remy Ann David

[edit: written before Remy's reply]
A mixer will not give you more recorded channels. It will mix your 16 (or whatever) channels down to stereo which you then record with your MBox and PT. You could then do some limited post production on the stereo result, but there would be no way of altering the balance between tracks or applying EQ or effects to just a single instrument or vocal.

If you are looking for more recorded tracks (i.e. a multitrack recording), you have gone the wrong way in buying an MBox-based PT system. About the only option you have is to use a 2-channel digitizing pre-amplifier with S/PDIF output, and that would give you a maximum of 4 channels at a time for tracking.

Otherwise, you could get a true multichannel interface and track using non-PT software, then import your multitrack into PT for mixdown.

It's the PTrap again.

Hey RemyRAD, thanks for posting those true words about high bit depths and sample freqs.
I happen to hang around in some german recording forums where some half-witted kids are constantly telling the newbies that you absolutely NEED "24/96 quality" for a decent home recording, 16/44 being outdated and obsolete.

Some wise guy in one of these forums once said, that using 24/96 will indeed help you to squeeze that last 0.02% of quality out of your recording.
He also said that there's no point in concentrating on that tiny little bit unless you haven't mastered achieving the first 99.8 Percent :)

But back to Johnny_Boi:
You said you just got into recording, so I assume you haven't done much work on that new mbox yet. There is, like remyrad said, no way to expand the numbers of inputs other than replacing that mbox with something that has the desired number of channels.
You are asking to record from 16 simultaneous channels, this is nothing that comes cheap. You might be able to get a basic Recording Rig that does the trick for a few thousand bucks, but then you'll still have to take all the other stuff into account: Mics, stands, cables, headphone amps, multicore cables, pop filters, shockmounts, racks, splitters. You'll quickly end up well above 10 grand with decent, but still basic stuff.

So my advice would be: start working with your mbox, start saving your money for the 16-input-studio. Ask a lot of questions here, gain some experience by recording lots of music.
Buy only quality stuff that will still be up to par the day you'll have completed building your 16-track studio in your basement.
Wait until you know exactly what youre doing, before deciding on a certain piece of equipment. Concentrate on good speakers next.

That said you might be able to pick up a Mackie console with firewire (such as 1240 or 1640 which both I think have the firewire option) which should let you record all the tracks at once.

Or am I misinformed and it's only the stereo mixdown?

*attack of sensibility*
*checks mackie website*

OK, first its the 1220, 1620 or 1640.
Second, it's all the channels, "up to 18 individual channels that show up in your computer as separate L/R inputs"

The 1220 + firewire IO card (which you would need) only costs about a thousand bucks, far less than the mystical 10g's stuff.