Home Recording Basics – The Audio Interface

In basic terms, an audio interface makes it possible for you to get sound into and out of your computer.

That’s it – that’s the sole purpose of an audio interface. It is your bridge between the analog and digital world.

An audio interface allows you to hook up microphones and other direct level devices such as guitars, keyboards and what not to your computer.

It then changes their analog signal into the digital 1′s and 0′s that computers understand.

This is called analog to digital conversion, or A/D conversion.

Most audio interfaces will also change digital back to analog, so you can listen to the music on headphones, studio monitors, or other speakers.

This process is, you guessed it, digital to analog conversion or D/A conversion.

Exciting stuff, huh? Well, it kind of is, if you’re a geek like me.

Can I Use My Computers Sound Card for Recording?

Is it possible to use my computers sound card for recording or do I need to buy a separate audio interface?

While it is very possible to use your computers sound card for recording, I would still recommend a dedicated audio interface.

In my early days of computer recording I used the internal sound card of my computer out of necessity.

I didn’t have a lot of money, and the audio interface options at that time were limited and expensive. Ah, those where the days…

How did it sound? It sounded fine. Though, todays dedicated audio interfaces sound a lot better.

Most consumer sound cards aren’t made to handle high quality A/D conversion, and won’t do justice to the signal you’re putting into them.

Though, if you’re on an extreme budget and want to get started making music, then by all means do so. Great songs and talent can surpass any limitations that gear may give you. Just my opinion.

Getting Connected

Audio interfaces will usually connect to your computer in one of four ways (*as of writing this). The connections are:

• Firewire – Avid Mbox Pro, Apogee Duet, RME Fireface, PreSonus FireStudio
• USB – Avid Mbox, Apogee One, M-Audio FastTrack, RME Babyface
• PCI Card / PCIe Card – Apogee Symphony, Avid Pro Tools HD
• PCMCIA Card – Apogee Symphony Mobile

Most computers will have at least one of these connection types – with USB being the most common.

Firewire was created by Apple, so you’ll usually find these types of connections on Mac’s. Though, they are available for Windows PC’s as well.

Most desktop computer towers have PCI or PCIe card slots. Though, you’ll find that not a lot of audio interfaces use this, and the good ones that do are higher end pieces of gear.

PCMCIA is a laptop card, and from what I’ve seen, there aren’t a lot of audio interfaces that utilize this. Though, there are some nice ones that do, such as the Apogee Symphony Mobile system.

Most of us that are recording at home on a budget will probably be using USB or Firewire.

Now, there are some other connections out there, but for most part, you won’t run into them unless you’re getting into very high end expensive stuff.

There are also new innovations happening all the time, so there will probably be new connection types in the future.

Computer Compatibility

Are you using a Mac or PC for home recording? Most audio interfaces are cross platform – meaning they work with either Mac or PC. But some only work with one or the other.

Apogee is great example of this. Their products will only work on a Mac.

You need to make sure before you buy anything, that it’s going to be compatible with your computer.

Also, if you’re looking at a certain audio interface, do some research on the internet and make sure that it will work with the specs of your computer.

I had a bad run in with the original Digidesign Mbox. I found out, after it was too late, that my computers chipset wasn’t compatible with the Mbox.

I actually purchased the computer and Mbox around the same time to to be used together. To find out that it wasn’t a good marriage was major bummer!

I eventually found a work around for the problem, but before I did I was afraid that I had waisted a ton of money. Ugh…computers can be very frustrating at times.

I’m happy to say that I now use an Apple iMac and Apogee Duet and the two work great together.

Input and Output ( I/O )

Input and output is just the amount of things you can have going in and out of an audio interface at one time.

The audio interface I use, Apogee Duet, only has two inputs and two outputs plus a headphone output. It can be limiting, but it works well for me.

If you’re a singer/songwriter, chances are you don’t need much more than this. Though, if you’re tracking a lot of instruments or vocals at one time, you will need more input.

Also, if you plan on doing any mixing outside the computer with external hardware (EQ’s, compressors, etc), you’ll probably want more I/O as well.

I mainly do all my mixing inside the box (inside the computer) using software plug-in EQ’s, compressors and effects.

While I would love to have some nice outboard analog gear, my budget tells me that it’s not going to happen.

Final Thoughts

I know it seems like there’s a lot of information about audio interfaces to digest, and sadly, I’ve only scraped the surface.

Though, knowing the basics should get you up and running.

Just remember, all an audio interface does is let you get sound inside your computer and back out again. That’s it.

Yeah, there is more to it than that, but I don’t see the need to over complicate things. Especially, if all you’re interested in is making music.

Now, if you want to be a professional audio engineer, producer, mix engineer, or mastering engineer, you may want to spend a little more time “geeking out” on the subject.

I know I’ve spent my fair share of time geeking out.

Well then, there you have it. The audio interface – one of the more important parts of your computer based home recording studio.

I hope this helps give you some insight into the basics of audio interfaces, and if it doesn’t, well then, you’re too hard to please! Just kidding!

I truly do hope this information helps with your home recording endeavors.