Blue's Snowball is very good for what it is: a condenser mic with a built-in USB interface.
Some general background. There are three basic types of microphones:
- Dynamic mics are really the equivalent of a tiny speaker that is used in reverse (sound goes in and voltage goes out, which is the opposite of how speakers are used). They can be useful in high-decibel environments but they can pick up a LOT of ambient noise (esp. where the input level isn't great). I have a handful of these (20 year-old SM57s, damned near indestructible) that are useful with a live band, but there are MUCH better dynamic mics out there now.
- Condensor mics are the next step up, these are actually a type of capacitor and that means they require a voltage (e.g. "phantom powered"). These usually have XLR connectors instead of 1/4" jacks, in part to power the mic. Some have a very focused sound field (cardioid), some have a wide sound field (omnidirectional), some have two condensors that allow you to switch between the two.
- Ribbon mics are amazing studio tools, they can cost a small fortune. I know a guy with a studio that has a pair ribbon mics that cost as much as a car. They tend to be delicate, too much sound pressure can actually ruin the ribbon. As I said, they are tools for specialists and require too much special handling for a hobbyist.
The built-in laptop mic you were using is almost certainly a cheap dynamic mic, and having it built into the laptop doesn't give you much in the way of options for getting an ideal sound field. So you don't have a wide sound field (i.e. its pathologically cardioid), you don't get much fidelity, and you get a lot of background noise to boot. And the built in A/D (analog to digital) converter is certainly not the best for recording a vocal group, its designed more for a spoken voice directly in front of the laptop.
The Snowball has a some features that would be great for you and a few drawbacks. It has an adjustable field (cardiod, omnidirectional), it has a decent A/D converter built-in (and is powered by the USB connector so phantom power or a battery isn't needed), and it turns out to be very good at recording vocals, spoken word (i.e. podcasting), acoustic instruments like a guitar, that sort of thing. You can also record individual vocals in separate tracks very easily in Garageband, to mix the individual track volumes and even harmonize virtually with yourself. The downsides are the price (about a benjamin), optional goodies like a shockmount or a pop filter cost extra, and the fact that this doesn't have an analog (1/4" or XLR) output, only digital. Nice for recording into a computer, but to record into a regular sound system you'd need a different (analog) mic. If that's the case (and it doesn't sound like it) you can get a regular analog mic and a USB audio interface. The Snowball is an all-in-one. It sounds really good for what it is, you could easily spend double that for a decent condensor mic and USB interface. You can spend less, but IMO that's the entry point for quality vocal group recording into your Mac.
Good luck!
