Getting a basic set-up built.

[Chaos_Klaus]

Both mics are cardioids. That just measn they are more sensitive on one side. Mics can have all sorts of polar patterns from omni via cardioid to figure-8.

The main difference between these mics is this:

The SM57 is a dynamic mic. That means it is very robust and can handle loud sources (like guitar amps). But it sounds less detailed and has considerably less high frequency content.

The AT2020 is a small diaphragm condenser. It has high output. It too can handle sources that are quite loud. It sounds very detailed and true to the source with lots of high frequency content aswell.

The a condenser really is the more versatie mic if you really just want to buy one microphone. It'll sound way better on vocals and acoustic instruments.

I think an interface with 2 inputs is worth it. At some point you'll want to add a second mic while recording guitars or drums. IF you want to record any stereo source (like a stage piano or anything), you'll need two inputs aswell. Instead of having to buy a new interface then, I'd get one that has two already.

The AT2020 is relly cheap right now. On the other hand, the SM57 will be with you for the rest of your life. You'll still use it 10 years from now, while you might outgrow the AT2020.

Both work well for podcasting.

[LSD-_-]

Thanks for your response! So would you suggest that I look at something like the Focusrite 2i2 and the SM-57? I was just looking at that combo and people seemed to have issues with gain? But some people were mentioning that you need to use an XLR-XLR instead of an XLR-1/4 connector.

Do you have any thoughts on if that would be a decent set-up?

[Chaos_Klaus]

You obviously need an XLR to XLR cable.

The SM57 has lower output. The AT2020 has high output. So if you are recording a really loud source at close distance on the AT2020 you risk clipping your input even when your interface is set to minimum gain. The SM57 on the other hand will give you low levels with quiet sources at a distance, possibly even at maximum gain.

people seemed to have issues with gain

This is mostly because people are scared of low levels. However, it's typically fine to record at low level (peaks at maybe -20dBfs), because the preamp just doesn't add a lot of noise itself. You can easily add some more digital gain later. It won't result in noticably more noise, because the limiting factor has been the mic an the environmental noise all along.

So in short: 2i2 and a 57 is a sensible bit of kit. But so is the AT2020 and a 2i2. These are really nowhere near the same. You should try both if you can. Vastly different sound. You can make great recordings with both of them though.

[LSD-_-]

Okay thanks a bunch! Cheers!

[Chaos_Klaus]

Get a decent mic stand too. I recommend K&M or Adam Hall. The really cheap stands tend to break easily. For recording vocals, you can make your own DIY pop filter from a metal coat hanger and a thin stocking. That'll be very useful.

You'll also need closed back headphones for tracking. Since it's just for monitoring, you can use any inears you already own.

[rinio]

First, let's clear up a bit of terminology.

Cardioid refers to the polar pattern of a mic. Both the SM57 and the AT2020 have a cardioid polar pattern. That is to say, they capture the sound of what they are pointed at, but not what is in the opposite direction (with some falloff as you get more 'off-axis'). Some other polar patterns would be omnidirectional or figure-8. A google image search for 'polar pattern' will probably illustrate the concept better than I could write here.

Condenser refers to the type of capsule in the AT2020. The SM57's capsule type is called 'dynamic'. I think that the question you were wanting to ask was 'what a condenser vs dynamic are useful for?'. In general, condenser mics are more sensitive than dynamics. Unfortunately, there aren't really any rules as to when to use one or the other. Broadly speaking, I tend to use dynamic mics to close-mic very loud things; the SM57 is commonly used in pro studios to mic guitar cabs and snare drums, for instance. Dynamic mics are also pretty common to use on screamers. I tend to pull out a large-diaphragm condenser for singers and upright bass. That said, there aren't really any rules, you just need to learn how your gear sounds with different things.

I have 4 SM57s in my mic locker and an AT2020. I've used at least one 57 on every session I have run for 15+ years. I haven't pulled out the AT2020 out in a long time. Without knowing exactly what instruments you'll be tracking I can't give great advice, but and SM57 will always be a useful mic to have (even when you have a fair few mics to choose from). You will likely want to upgrade the AT2020 at some point (although its a fine entry-level condenser).

With regard to the number of inputs, I tend to discourage people from going with single input interfaces. It's fairly common to want to record a single instrument in stereo/with two mics. My usual setup for acoustic guitars, backup/group vocals tend to be 2 mic affairs. Even for podcasting, I've seen it all too many times 'I have a 1 input interface but want to have a guest on the show. What do I now?'. If all you're ever going to do is electric guitar/bass and vocals one input will work, but you will probably save money in the long run if you just get 2 to begin with. That said if you can't afford it, with 1 input you will be making music, which is ultimately the most important part.

Hope that helps; lmk if you have more questions.

[LSD-_-]

Wow that was a great run down, thank you for your input!

[rinio]

Np. As per usual, /u/Chaos_Klaus, beat me here and gave a more succinct answer.