The Linux-Based Recording Studio
The Linux box is your digital recorder. The decision to make here concerns software. Literally hundreds of open-source audio applications are available for Linux, from hard-disk recorders to MIDI sequencers to MP3 encoders. I don't have room to talk about them all, so I focus on my main studio tool, Ardour. (See the Where to Start section of the Resources page on the Web for more information on finding software.)
You can Google your way to most software, but there are some great package resources out there. I'm on Red Hat, so I use Planet CCRMA. The Planet is a project at Stanford's Center for Computer Research in Music and Acoustics, maintained by a knowledgeable guy named Fernando. Not only does Nando maintain Red Hat RPMs of most audio and video applications, drivers, utilities and even custom kernels, he has an extensive guide for installing kernels, ALSA sound drivers and software, as well as for tweaking your machine's performance. I highly recommend reading through the Planet, even if you're not using Red Hat. There are other similar resources for different distributions.
To quote the Ardour home page, “Ardour is a multichannel hard-disk recorder (HDR) and digital audio workstation (DAW). It is capable of simultaneous recording of 24 or more channels of 32-bit audio at 48KHz....” Ardour needs a 2.4 or later low-latency kernel, 0.9 series or later ALSA sound drivers and JACK (Jack Audio Connection Kit). It also needs a window manager because it doesn't run from the command line like many other Linux audio applications. I run Ardour from Fluxbox and sometimes KDE, but most managers should work.
Ardour should be fine with any sound card supported by ALSA. Part of why I use the HDSP is because Ardour was written with RME's cards in mind. Ardour looks and acts a lot like Pro Tools from Digidesign.
Starting Ardour is a matter of starting JACK and then starting Ardour while JACK runs. It's best to run these as the superuser, because only root is allowed to invoke real-time priority. A generic start command for JACK would be:
jackd -d alsa -d hw:0
This starts the JACK server using ALSA as its device, and the default sound card as ALSA's device. See the JACK User Documentation to learn more about command-line options for JACK.
Like Pro Tools, Ardour is very powerful. You can create as many audio tracks as your hardware can handle, record tracks, mix internally, apply plugins and route them any way you and your sound card can imagine. A typical session for me might see 20 Ardour tracks routed to 20 separate card outputs, and eight more tracks submixed within Ardour and sent to two more channels of output, all mixed on my digital mixer. It's relatively easy to do this. I simply click on the Out button, toward the bottom of each track in the mix window (Figure 5), and choose an output channel from a pop-up list.
Another option is mixing totally within Ardour and exporting the session as a .wav file. The mix window has graphical faders, exactly like Pro Tools, as well as plugins and automation. Automation is as simple as clicking arec, moving your settings, then unclicking arec and clicking aplay to play back the automation.
As you can see, using Ardour is as straightforward as any professional DAW, which isn't totally straightforward, but it doesn't take long to learn. Because it's in beta, the manual is forthcoming, although a read through the Pro Tools manual should provide a good idea of how it works. There also are some good HOWTOs on-line (see Resources). At the time of this writing, Ardour is at 0.9beta8-1. It's important to keep this in mind, save often and don't be alarmed by the occasional crash. You can help get it to version 1 by reporting bugs (see Resources).
Studios consist of some combination of control room, recording space and isolation rooms. If you've got the space, you can have all of them; if not, you may be limited to only your control room. Figure 6 is a typical studio floor plan; Figure 7 is my studio's floor plan.
Some people get expensive rigs, put them in an office and call it a professional studio, which is far from the truth. The best thing you can do to improve your recordings, better than buying $5,000 US microphones, better even than 77-string custom guitars made by Beelzebub himself, is improve your studio's acoustics. There are two areas to consider, recording space and listening environment. It's easy to be off the mark with your recording space and easier still to be dead wrong in your listening space.
You should find some information about bass traps, no parallel surface rule, diffusion, absorption, isolation, flutter echo, reverb times and the like on the Resources page on the Web. Then you can start deciding things like where to place furniture and acoustic material, finding a good room that's not a hallway next to a jackhammer and so on.
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