Audio interface explained

Audio Interface - If you want to do most of your recording on your computer, then having a professional soundcard is an absolute must as the quality of the sound produced is based on this important piece of hardware. But before we proceed further into the details, a brief description of what a soundcard is and how it fits inside your computer.

Soundcard vs. Audio interface
A sound card is a hardware that lets you record and playback audio. It sits inside the computer in a PCI slot and you connect all the cables at the back of this card. Professional soundcards, also known as Audio interfaces, on the other hand has a box that sits outside the PC and a cable that is connected to the PC, either to the PCI card or to the USB/Firewire slot depending on the type of the interface. The breakout box contains slots for all the input and output audio/midi connections.

Drivers & DACs
Now, let us go a bit deeper into the technicalities. Drivers and DACs are the two components that have a major impact on the performance of your soundcards. The better the quality of these two things, the better the sound is going to be. These are one of the important reasons because of which the professional soundcards cost more than consumer soundcards.

Drivers are the software components that allow audio computer programs to talk to your soundcard; they come along with the card. The drivers basically manage the traffic of data between the CPU, DAC and the audio application as and when it is needed.

DACs are converters that are physically present on the soundcard. The converters job is to read the incoming analog waveform and transform it into digital data. This important process is known as "sampling' and it determines the quality of your recorded sound. Once the digital data is on your computer, it is very easy to manipulate it in different ways and store it on your computer.

Limitations of consumer soundcards
With a brief background on the internals of a soundcard, you will agree that although most of the consumer soundcards that comes built-in with your computer can be used for audio playback and recording, these soundcards are not meant to be used for music production. Some of the limitations of a consumer sound card include:

• High latency (delay in the reproduction of sound, between initiating a sound and hearing it)
• General sound quality is not great
• Low sampling rates (recording quality is poor)
• The drivers may not work with most of the audio recording software applications
• No MIDI port. You cannot connect external keyboards/synths
• It is intended for home and office entertainment use. The emphasis is more on playback and casual use

Advantages of using an Audio Interface
Professional cards, AKA Audio Interfaces, on the other hand, do not have the limitations listed above making them suitable for serious audio work. Some of the features on a professional soundcard include:

• Low latency sound recording and playback
• Usually follows the ASIO protocol (suited for sound engineering and music software)
• Comes as external rack-mountable units which can be connected using USB 2.0/Firewire
• Large number of input and output connectors
• Hardware support for multiple input and output sound channels
• Higher sampling rates compared to a consumer soundcard
• Multi-channel data recording and real-time audio mixer and processor

Choosing a professional Audio Interface
You will need to select a soundcard depending on what sort of studio setup you want to have. You will have to make sure that the soundcard has inputs/outputs to connect to most of your gear. In general, the following are some of the instruments that you will need to connect to your soundcard.

• Microphones
• Control surface (if you don't have a mixer)
• Audio speakers (AKA monitors)

You may also need external Preamps to raise the level of your mic's. Though most of the soundcards have built-in preamps, only the more expensive ones have really good preamps. Besides the above mentioned gear, most of the other things like compressors, gates, Reverb and other special effects can be used as software in your Computer. So you do not need connections for these.

Driver Problems
Another thing to consider while choosing a soundcard is to make sure that the drivers will work on your computer/operating system. This is actually a tricky area since the drivers behave differently on different machines. Even if it works, you may have to download a different set of drivers whenever a new operating system is launched.

Just make sure that the soundcard you wish to buy comes with drivers for your operating system, comes with updated drivers from time to time supporting the latest service packs and operating system updates, has a site from where you can download drivers and works with your audio application (Cubase, Sonar, Reason, etc).

Connecting your sound card
So how do you connect the soundcard to your computer? It can be done in either of these ways - PCI Interface, USB, Cardbus or Firewire. Out of these, only the PCI interface goes inside the computer, into the PCI slot. All the earlier soundcards used to be available only in this type and these soundcards can only be used with desktops.

The other interfaces are external in the sense that the main box stays outside and a cable connects the box to the computer. Of all the external interfaces, the firewire interfaces are getting good reviews and are known to give good performances. It gets connected to the firewire port and can be used with laptops as well as desktop. They are very easy to connect and they also give you the option of portability.

Manufacturers
Some of the major and popular manufacturers/brands of professional soundcards include M-Audio, RME, Tascam, MOTU, PreSonus, Digidesign, Onyx, etc. With an overview of what things to look for in a soundcard, I think you should be able to find a soundcard that suits your needs the best.

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