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.
