The Linux-Based Recording Studio
I grew up using keyboards. Cold-war grey TRS-80s, green-screened Apple IIs, IBM clones, 8088s, 286s, PC-DOS, then Windows (missing the command line) and finally UNIX command lines. Later, the recording bug bit me and took me away from the command line and into studios. I still was a PC guy, but there never was a reason to bring a computer into the studio. Affordable hard drives and memory were too small for audio, sound cards were junk and processors were too slow.
Then, Linux came along. Sure, I had to wait for hard drives to get bigger and chip speeds to increase, but even after that, proprietary software still was way out of reach. So I upgraded my studio, learning a lot about Linux along the way. Here, I share a bit of what I did in my studio and explain how you might start a Linux-based studio. General information about Linux audio and recording is vast, so I refer you to further resources where appropriate (see the on-line Resources section).
Like anything, what you need to buy for your studio and how you set it up is determined by a few key decisions, especially when it comes to studio hardware. The hardware is easy as 3.1415. Anything that runs Linux can run Linux audio applications, but bear the following in mind:
Audio uses 5MB per track minute at CD quality (44.1KHz, 16 bit), meaning a three-minute song recorded in stereo takes up 30MB on the hard drive. Multitracking uses more than two tracks. A typical project of 24 tracks that is three-minutes long would use 360MB, not including captured audio being used.
Slight upgrades to things like RAM size and CD-ROM speed are nice if you have older equipment. A CD writer is your friend, too, as you might have guessed.
Some bad video cards introduce noise into the sound card.
Drivers in Linux are sometimes hard to come by, so read and ask around before buying hardware, especially sound cards.
Acquiring software is almost as easy. Latency needs to be low, so the kernel needs a bit of a tweak in the form of a low-latency patch. The hard drive needs to be tuned correctly too. This subject is more than I can cover here, but check out the Resources on the Web for other readings. Also, keep a dual-boot system with Microsoft Windows for troubleshooting. You may need to test hardware on another operating system to narrow a problem to a Linux driver, or you may have tasks, such as upgrading firmware, that need to be done on a Windows box.
Now that we've got the box, it's time to decide what studio hardware we need. I like to think of the signal flow for a given project, and that tells me what I need. Figure 1 shows the basic concept of where a signal goes in a recording project. Also take a look at Figures 2 and 3; 2 is a wiring scheme for a simple studio and 3 shows my studio's scheme. I begin with the lynchpin, which actually is a couple of rungs down on the signal chain.
The key to digital recording is analog-to-digital and digital-to-analog converters (ADCs and DACs). In other words, you need to get sound in to and out of your computer. In both directions, you have some decisions to make.
ADC must be done in order to record. This happens in the sound card, in a digital mixer or in a standalone ADC.
Getting sound out (DAC) consists of two parts, listening (or monitoring—more on that below) and mixing. When mixing, you might never convert back to analog. You might mix digitally inside or outside the computer, saving a mix as a .wav file or transferring digitally to a digital recorder. The thing to understand here is that at some point before you can hear it, a DAC must happen. If you've done everything digitally, make a CD and play it in your car, that's where the DAC has happened.