Perhaps the easiest way to begin understanding the wide world of interfaces is knowing their different physical forms, or configurations. Following are the three primary interface configurations, or physical ways an interface hooks up to your computer.

Soundcards

The simplest, cheapest, and oldest of the interface configurations is the soundcard. A soundcard is a collection of chips and other electronic components on a flat circuit board, or card, that plugs into the PCI slots inside your computer case. The card has jacks (connectors) that stick out the back of your computer's case and remain exposed after you insert the card and close the case back up. You then plug your instruments and other music-making devices into these jacks. Very often a computer comes with an included soundcard, which is just fine to get going on your recording projects, though you may find you want to upgrade after a while.

The process of installing a soundcard is simple. Just follow these steps:

1. Remove the soundcard from its packaging and note that it has ports that will protrude out of the back of your computer and gold tabs that will insert into the PCI socket on the motherboard, as shown in the below figure.

2. Open your computer, choose an open PCI socket that the card snaps into, and then work the card into position, making sure the ports will stick out of the back while simultaneously lining up the tabs with the socket, as shown in the below figure.

3. Press down gently but firmly with both hands. Be careful not to rock the card in any direction, but rather press it straight down.

4. Reattach the mounting-plate screw to secure the card, put the cover back on, and that's it! The ports remain exposed so that you can make computer-data and audio connections.

Soundcards with Breakout Boxes

A variation on the soundcard is the soundcard with breakout box. Because there are only so many connectors you can physically cram onto the exposed plate of a soundcard, interface makers quickly devised the breakout box to accommodate more jacks and other circuitry. The breakout box is connected to the computer's card with a special multiwire cable and can be conveniently placed (which the back of a computer can't always) in a case or rack that is 19" wide, the standard measurement for rack-mounted audio gear. A breakout box often has switches and knobs for added control over the sound, even before it hits the computer.

USB and FireWire

One of the most welcome improvements in computer communications ports is the jettisoning of "the traditional multipin serial and parallel ports in favor of USB and FireWire. In addition to standardizing the hook-up procedure for peripherals such as keyboards, mice, printers, and scanners, USB works very well for audio and MIDI. You can't do heavy-duty audio multitrack work with USB because it's only reliable for about four tracks of simultaneous audio, but that's enough for a lot of projects, or even a session that might not need more than four tracks of simultaneous audio until a later time.

FireWire (also known by its engineering name, IEEE 1394) has been included on all Macintosh computers for some time but is easily fitted to Windows machines with a PCI or PCMCIA card (less than $40 and S30, respectively, at the time of this writing), and it's much faster than USB. Consequently, FireWire can handle pro-level multitrack projects, but it's used on more expensive interfaces.

What's nice about USB and FireWire is that no cards are involved, so they're much easier to hook up. You just plug them into your computer's ap­propriate ports and you're done; no messing around with opening the case. It also means that one interface can be shared between a desktop and a laptop with no additional hardware. As icing on the communications cake, both USB and FireWire devices are hot-swappable, meaning you don't need to power down your computer and restart it to hook up or swap peripherals.

When going with a USB device, you can purchase inexpensive two-channel audio interfaces or go with the higher-end four-channel devices that include more controls and features. Beyond four channels, USB isn't fast enough to support a simultaneous audio stream reliably. That's when you consider FireWire interfaces, such as Mark of the Unicorn's 828 and 896. Their operation is not much different from USB: You just plug them in, install the software from the CD-ROM, and start passing audio through your system. USB has enjoyed an upgrade to 2.0, so it will be a viable communications protocol for audio and MIDI for some time. FireWire is gaining in popularity due to MOTU's efforts and high-end devices from Digidesign and RME.

Virtually all recording is done digitally and can therefore be easily integrated into computer tasks. Though some analog recording still goes on, most of the world now records music digitally—and of course anything on a CD has been through the digital process at least at the end of the line. So where traditional recording involves a mix of machines and technologies, computer-based music production keeps the process entirely within the digital domain from start to finish. That's a highly efficient way to make music, and it gives computers tremendous advantages, both sonically and economically. It helps to understand just how audio is recorded digitally, regardless of the technology at hand, before dealing with the tools that aid in that process.

Following is a brief rundown on the five key steps in turning a musical idea into a finished CD.

Recording

To most people the word „recording“ refers to the entire process of storing music on a machine. But to recordists, recording is specific to the initial capturing of the musical performance onto disk. In the lingo of recordists and musicians, tracking is used synonymously with recording, because it also refers to the laying down of a musical performance to a track—once a linear channel on a tape and now a convenient metaphor for hard disk-based recording.

Recording is where you sing into a microphone and where instrumentalists all assemble in a room and bang, blow, or scrape on their respective instruments. It's the part of the process that involves the musicians and their performances, and it's arguably the most critical situation musically and artistically, because that's the stage where the performances occur. But for the recordists, it's only the beginning.

In theory, if the musicians perform perfectly and nothing goes wrong, all that's left to do is stamp the CD. Fortunately for us recordists, this is seldom the case, and we get to tinker with all sorts of aspects of the performance along the way to the master product. The following figure shows the signal path in the initial recording stage.

A subset of recording is overdubbing, the overlaying of additional musical material after the initial musical elements have been laid down.

Overdubbing involves musicians listening back to the previously recorded material and contributing new parts—such as harmony vocals, instrumental fills between sections, and added instruments to bolster the originals.

It is overdubbing that allows artists such as Stevie Wonder to play all the instruments on his albums. He can't play keyboards and the harmonica simultaneously, but he can do the next best thing: play and record the keyboards first, listen back to the track, and play the harmonica along in perfect synchronization with the keyboard part. He and other musicians can do this by using a special machine called a multitrack tape recorder. And now the computer can act as a multitrack as easily as it can a flight simulator or word processor.

Editing

After recording the music, the next step is editing. This is the stage where you as a recording specialist go back and examine the musical performances for their quality and make adjustments to the sound.

Small-scale editing (or micro-editing) involves correcting bad notes, deleting noises (such as a breath or lip smack before a vocal entrance), and other spot fixes. Large-scale editing can involve copying whole sections of music (such as the song's chorus) and pasting them in different places of the song. In this way, editing music is like word processing. The digital aspect of music makes it very easy to cut up into its various discrete components and reorder them with seamless results.

Mixing

Mixing is the process of taking all the separately recorded tracks in a multitrack project and blending them together in the desired balance of volume and sterec positioning. Mixing is also where you add effects, such as reverb and equalization (EQ), to your sound. In analog times, the mixdown deck was separate from the multitrack deck, so it was obvious that these two tasks were separate. In digital times, you're not only using the same machine to do both, you're using the same piece of software. So it helps to remember that the processes are different enough to be considered as separate artistic tasks.

Mixing is still a stage that one goes through even if there are not multiple tracks to blend. For example, if you're recording a vocalist singing an unaccompanied melody, you might wonder what there is to „mix“ after the original recording. Even if everything is perfect from a performance perspective, chances are there's still some global control you'd like to make before sending the initial recording to CD. Most likely, you'd want to add some sort of effect, such as reverb, EQ, or compression (level control). Many people avoid putting effects (especially reverb) at the tracking stage because they prefer to leave the raw track untouched and record effects at the mixdown stage. If you record reverb at the tracking stage, you won't be able to separate it out later on. But if you wait until mixdown, you can experiment with different amounts and types of effects without permanently altering the original.

A lot of people think that whereas tracking is merely getting the sound onto disk accurately and with no mistakes, mixing is an art form. Tracking can be workmanlike, and mixing allows you to show a little flair, but both are equally important in producing a successful end product.

Mastering

Mastering has twin meanings in recording. It can refer to the process after mixing, where further tweaks are made to the finished mixdowns, and it can sometimes mean the process of making the master CD itself. For our purposes, we'll leave the creation of the CD to the burning stage and use mastering to denote the process of smoothing out the mixed tracks.

Even after a careful mixdown, you can listen to individual mixes of separate songs and sometimes hear disparities. Song 1 might sound louder than Song 2, or the bass on two different songs with similar instrumentation might sound drastically inconsistent from a tonal perspective. Mastering is the process that takes into account and deals with these issues, and it gives your recordings an overall professional sheen and consistency. Mastering is particularly important in creating an album, suite, or any collection of material where you want to preserve a continuity of sound between songs as well as within individual songs.

Burning

This is the simplest and most intuitive of all the processes in the recording chain. It's the part where you take your finished work (in the form of a stereo digital file) and transfer it to a CD. It's called burning because you're actually using the drive mechanism's laser beam to etch data (pits) permanently into the compact disc medium. Virtually all new computers come built with a CD-burning drive, and it's a simple matter of using software to operate it. Of course, you need to supply the blank CDs, but these are sold everywhere, including pharmacies and record stores. Current prices of blank CD-Rs (the write-once variety) are less than a dollar apiece (cheaper if you buy in bulk and at discount sources), so they're cheaper than cassette tapes (remember those?).

Burning completes the process of start-to-finish music production on the PC. When you consider that you can take your most fleeting musical impulses idea for a melody, a synth texture, a percussion loop—and draw it, play it, import it into the computer, and then, several steps later, burn it onto a disc that plays in your car, your DiscMan, or your brother-in-law's boom box, that's pretty impressive. And it's not only possible, it's actually easy.