Computer Audio Recording – Working With Audio

Computer audio recording - the economical way of recording audio. It used to be that a recording studio used tons of specialized, expensive gear. After the preamps pumped out the line - level signal, it went into a high quality mixer or recording interface, which captured the audio on tape reels. To do a mixdown, all those tracks must then be routed through a mixer, and the engineer had to learn how to do the mix - what level each track must be at, and when to fade in or out. This was then caught on a two track recorder. 

But now, computer audio recording changes all that. Instead of complicated recording interfaces and steep learning curve mixing, now you can plug the mics into a computer interface, bring up a software program, and record directly to hard disk. As an added bonus, it is now digital, meaning it will not gradually lose quality as you play it over and over.

When you go to mix the tracks, that all happens on the computer, digitally. You can put custom effects on each individual track, or selective groups of them. You can control volume and pan in extremely fine ways. You can program the mix to come out exactly the same, time and again. Computer audio recording is great!

So lets slow down and take a closer look at things. We will look at what is required of the computer for audio recording, what kind of software you will need (both bare-bones, and what is nice to have), how to connect the computer to the microphones, and how to make it all work together.

Computer Audio Recording 1: The Computer

Almost any computer will work for computer audio recording. Obviously, if yours was made in the last millennium, there's a good chance it won't be powerful enough, but to do basic 2 to 4 track recording, anything with a gig of RAM, free hard drive space, and a processor faster than 1gHz should easily do it.

The basic rule of thumb for how much computer power you need is this: the faster and stronger your computer is, the more tracks and plugins you will be able to use. I use a PowerMac G5, dual processor (I think the speed is about 1.8gHz), with 3GB of RAM (that's even overkill). I have a second internal hard drive for the audio files, which works pretty good. This setup works fine, and provides enough power for many tracks (usually don't use more than 8-16) and lots of plugin power for my Waves plugins.

When you start using more tracks, the first thing to give you trouble will probably be the hard drive. When you play music on the computer, it must load all that data from the hard disk before it can process and play it. A 16bit mono WAV or AIFF file contains about 100KB of data per second, so just imagine when you get 20 tracks going - several MB per second! Then, if you get into samples and MIDI stuff, you have more data throughput. The good news is that audio is not as demanding as video is, so you won't need the top of the line, cutting edge technology. An internal SATA hard drive is plenty fast for most computer audio recording. 

You can also use a laptop for computer audio recording. Keep in mind that for bulk processing power, a comparable desktop computer will have more power than a laptop, but laptops work fine. You'll probably want to use an external hard drive, but otherwise, a laptop will provide sufficient recording power.

When I go to record a choir in a church or some other location, I'll take my laptop to do the recording, then bring the files back to my studio desktop to edit and mix. It's kind of a matter of preference - my laptop is a new MacBook Pro running at 2.4gHz, so it can easily handle the editing part, but my studio is set up with the monitors, computer screen, and everything, so it's just easier that way. 

Plus, I like having something dependable in the studio. That computer is not connected to the internet, so the only changes are ones that I know I made.

Computer Audio Recording 2: Software

You don't need much software to begin computer audio recording, but there are better and worse options available. I see the options as basically these: free, budget, and professional level. It is possible to do a mix on any of these (theoretically), but the farther up you go in price, the more features and tools you get.

I record on a Mac, so the software I use is Mac specific. MOTU's Digital Performer works excellent for what I need. I do specifically audio recording, without MIDI integration, but Digital Performer does it all. It comes in at the upper end of the price scheme, but it does what it does very well. 

AudioDesk is another product by MOTU that I started with. They ship it free with some of their computer audio recording interfaces (that's where I first got it). I started using AudioDesk, then stepped up to Digital Performer.

A friend of mine uses Steinberg's Cubase program, and he likes it. I never used it, so I can't make a judgment but it's worth checking out.

There are free options available that you can check out. It might be good to have Audacity on your computer, just in case, but I like to have something more powerful to work with. It will just save you a lot of frustration and hair pulling. On the flip side, don't buy a brand new program, and expect to use it the next day - it takes time to learn. 

Computer Audio Recording 3: Interfacing

So now we have this computer, equipped with just the right software program, but now we need some way to connect the mics to the computer. Enter, the computer audio recording interface!

An interface is something that works between two systems, allowing them to work together. For instance, your keyboard and screen are interfaces, allowing you to work with your computer. In the world of computer audio recording, the two systems are the computer system of USB, FireWire, and digital data, and the audio system of XLR cables, 1/4" TRS cables, and analog sound.

A computer audio recording interface will take the analog line-level audio signal, convert it to digital, and send it along a USB or FireWire cable to your computer, where the software routes it to the hard drive. Interfaces come in many shapes and configurations, but the principle is the same - a go-between for the computer and the audio. 

An interface has three basic ways of connecting to a computer: USB, FireWire, or a specialized cable connected to an expansion card slot in the computer. The latter way is for higher end, more powerful interfaces, but that doesn't mean a FireWire or USB interface can't be powerful. I use the MOTU 828 interface, a FireWire based system. FireWire provides well for at least 8 channels of audio. The 828 has capacity for 24 channels, so you can see that it will be hard to require more power than a FireWire system can offer.

My 828 can accept a wide array of inputs - 8 analog inputs, with TRS 1/4" connecters, 2 XLR mic cables, with included preamps, 8 digital inputs via the ADAT Lightpipe interface that connects to my Presonus DigiMax, or 8 digital inputs via a TDIF protocol. All in all, I can record 24 channels at one time onto my computer.

There are smaller interfaces for computer audio recording, some of which I highlighted while talking about laptop digital recording, small pieces with just a few channels for mobile recording.

Another thing that goes with computer audio interfaces is drivers. Don't be caught without one! A driver is a piece of invisible software that allows your recording program to communicate with the interface. Any equipment manufacturer will supply a disc with drivers on, and with most, you can download directly from the manufacturer's website.

Computer Audio Recording 4: Working Together

When you have all the components hooked up together, you are ready to roll! Plug the mics (or preamps) into the interface, fire up the software, warm up the voice, and hit record! All is supposed to work well, and it should, provided you understand all the above and plugged everything together correctly.

From here on out, it requires learning how to use the software program, how to make it work the stuff you want it to. After you master the basics, it gets to be really fun. Trust me! Computer audio recording is a blast.

Have questions about computer audio recording? Not sure how to hook up the gear? What software program to buy? Which interface works with analog signals? We're open to help. Please ask your computer audio recording question here, and we'll see what we can do to help. 

About the Author Lee Weaver

Lee started his career in recording with an auspicious goal - record tracks of his own voice singing in harmony. As a hobby project, it didn't have the funding to go to a studio and pay for someone to do it for him. Like many of you, he pulled himself up by the bootstraps to learn the art of recording.

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