How To Intelligently Buy The Best Audio Interface For Your Home StudioFeb 8 — By The Tweak Contents ↓
The Bell rings, a fresh class of newbies usher in, eager to get started with digital recording. "My goal", starts Tweak, his quiet voice trying to rise above the hub-bub, "is to keep you from making a serious mistake and save you money". A hush falls over the crowd.
Ok, lets go. People ask me all the time, "What's the best audio interface for my studio". You know, that's like asking someone what is the best car on the market, or which all night restaurant has the best coffee. "Best" is a 4 letter word; please don't ask me what's best, even if you can afford it (We'll start you with an Apogee Native Tools which lists about 8 grand). There is no universally acclaimed best audio interface. Best for what? PCs? Macs? For running Sonar? Cubase? For a pristine 3.6ghz 64 bit DAW or a lowly Pentium III 550? For a computer that has the notorious VIA motherboard chipset? For under $200? $500? $1500. For Win XP before SP2? For Mac OS 10.39 or OS 10.4?
Even with all that information, is there a definitive answer out there? Not really. Unless someone is whacked enough to buy every interface/soundcard in existence, test them all on every OS/CPU configuration and have enough sanity left to recall the results. But we can steer you towards some of the better choices available today, armed with that info.
Audio Interface or Soundcard?
Over the past few years, musicians have been opting for an audio interface (AI) over the standard soundcard. These may be either PCI or Firewire. The AI typically has a breakout box that sits outside the computer and a cable that is connected to either a PCI card in the computer or a USB or Firewire cable. On this breakout box are a number of connectors for cables that go to your instruments, mics, mixer or monitoring system. The conventional soundcard, on the other hand, just sits in the computer in a PCI slot, the cables hang off the back of the card.
The audio interface type of system is often said to be better because the cables stay away from the fierce electrical fields that surround the modern computer. True? Well, that argument does not hold a lot of water, and it doesn't bother the guys running hi-end RME and Lynx cards. But this argument does...
Tweak crawls under the desk in the classroom and lays on his back, pulls out a flashlight, rips off his glasses pulls out a magnifying glass and shouts out "How in the bloody heck are you supposed to read which is "In" and "Out" on this thing?".
Ha! With a breakout box you don't have to lay on the floor under some desk to connect it up and you can move your noisy computer farther away--always a good idea when recording audio.
Audio interfaces also sometimes allow for balanced audio connectors instead of the unbalanced 1/8" stereo jacks one sees on most consumer oriented soundcards. If you want the cleanest possible recordings, then go with an audio interface that has balanced connectors. We'll get into that on page 2. For now, just note that balanced does make a difference, particularly if you need to run cables longer than 10-12 feet. Keep in mind that not all soundcards are bad, and we'll go through some great ones in a bit.
Digital Audio Converters
There are two parts to every audio interface/card that affects the sonic performance profoundly. The first are the software drivers that come with the card. The second is the quality of the digital audio converters (DACs) that are physically on the card. Audio interfaces may have mic preamps, and these to can affect the quality of your recordings. We're going to talk about all these elements. But first, lets get to the DACs.
Most interfaces and soundcards on the market have acceptable quality DACs these days, compared to a few years ago when you had to spend premium dollars to get good DACs. It makes sense if you think of your CD player when thinking of the quality of DACs. Early cd players had a harsh sound to them and were often considered "brittle". As a result of that criticism, audio engineers found ways to make the DACs sound better, with oversampling, error correction, interpolation and other ways to "smooth" the output. At the core of the DAC is a process called "sampling". The converter "reads" the analog incoming waveform and transforms it into numbers, or data. Once it is data, the computer can manipulate it in many different ways, store it on disks, merge it with other data, and so on.
The DAC determines how good the unit sounds. Whether an interface is USB, Firewire or PCI does not affect the sound per se. These are just methods of shuttling data. The converters actually touch the sound. But there is more to a quality interface than just the DACs...
Someone shouts from the back row, "Tweak, dude, just tell me who has the best DACs so i can buy my interface!" (Tweak suddenly turns red and veins start popping out of his tweakly neck) Hmm, there's that "best", that 4-letter word again, his voice rising to creshendo. "OK class, Mr. Newbie "gotsta know right now" wants to know the best DAC, can anyone help him?" Someone shouts out "Pro Tools!" Tweak ejects the person from the classroom like an umpire at the world series. The class nervously squirms as Tweak paces the aisles of the class. Anyone else want to answer that one? The someone in the front stands up and says: "The point is you can't hear a DAC without the audio going through a software driver. If a card has a great DAC and a crap driver it is a worthless card" Tweak smiles in delight and gives the speaker a gold star. Someone else shouts "Hey, that's not cool if audio interface makers actually release stuff with crummy drivers, do they really do this Mr. Tweak? The Tweak looks down, searching for the politically correct words. Someone else yells out "Yes they do!" [I didn't say that.]
Professionals that are concerned with the quality of digital analog conversion will buy an outboard DAC that connects to that interface's digital input/outputs. These effectively bypass the DACs on the interface. When you need the absolute highest quality, you bite the bullet and add outboard converters, which you can add at any time to any soundcard or interface that has s/pdif (digital i/o). Read more about digital audio converters.
Can you do listening tests on these DACs? Yes, but like all tests of this nature, your ultimate assessment is subjective. Also, to hear the difference you need superb monitors, an excellent listening room, and a squeaky clean signal path. That being said, record a full mix and then record just its cymbal track. Listen to the quality of the cymbals alone, and then again in the mix. The DAC that best preserves the hi frequency shimmer and definition without smearing or artifacts can be considered better, given the rest is equal. This is one of the 1st places a bad DAC will mess up. You might also want to evaluate on the basis of warmth, fluidity and whether your ears "like" the sound.
Ok, I know a lot of you are going to want to get the AI with the "best" DACs like Mr. Noob above. It might even make you sweat before a purchase, and sway you to pick an interface you would not otherwise. You are better off getting the AI you want for its i/o and drivers. You can always add DACs later, and they will be better than the ones on nearly all of the soundcards and interfaces. After you get your monitors and maybe one hi end preamp, then you should start thinking about converters. Until you get those items, you won't hear that much difference. If you absolutely need great DACs on your soundcard/interface, consider the RME Fireface.
So what is a software driver, and how does it affect audio performance? The driver is the critical code that manages the traffic of data going from the cpu to and from the DAC. It organizes the data so the CPU can fetch it when the audio application says it is needed. There are certain rules the driver has to follow that are set by the operating system. The application and the CPU have to follow the rules, and if the driver interprets the rules properly, all will work. If there is a flaw on the application side or the driver side, things are going to mess up. If the poor CPU can't get the data the 1st time, it might try again. And Again. And Again. What just happened to your audio, dude, it stopped? "CPU overload, eh?" Wonder why companies are often finger pointing at each other when users protest? Hehe "Company Z's driver is is garbage", or "The problem is in Company X's application, we asked them to fix it but they have not responded". Sound Familiar?
Drivers are very hard to perfect. What might work great on some machines, work's terribly on others. This is what makes the decision so maddening. If you are on a PC and Microsoft introduces a new OS, or changes direct X, then your soundcard/interface may stop working well. It's like building a house in an area that has an earthquake every 3 years or so. Some motherboards actually get in the way of audio flowing to the CPU and if the driver is not aware of these issues, the audio will get hurt.
OK. you doin' OK? I know some of this is tough, but I have to set you up right, so you really know this stuff. On the next page we'll talk about the preamps on audio interfaces and then talk about the different ways they shuttle your data around. You'll also get my little crib notes on nearly every audio interface on the market.