Contemporary musicians employ the computer as a digital audio workstation (DAW) to perform a wide variety of tasks dealing with sound. Typical uses include recording and editing soundfiles, adding effects and dynamics processing and preparing audio tracks for a CD master disc.
The centerpiece of the modern musician's computer-based studio is the hard-disk recorder (HDR). Musicians working on Apple or Microsoft Windows machines have an impressive selection of HDR systems to choose from, but until recently Linux users have had nothing truly comparable for professional work. A professional-quality HDR is a profoundly nontrivial programming endeavor, and proprietary HDR developers have provided little technical guidance for would-be designers of an open-source DAW.
Today, thanks to the talent and perseverance of chief designer/programmer Paul Davis and his talented crew, Linux musicians now have a native-born professional-quality HDR/DAW, named Ardour.
Ardour is a multitrack recording and editing system for high-quality digital audio. Ardour supports audio processing plugins (LADSPA and VST), parameter control automation, sophisticated panning control and many advanced editing procedures. Recognized synchronization protocols include MIDI time code (MTC), a means of encoding SMPTE time code to MIDI; MIDI machine control (MMC), a set of MIDI messages for controlling transport features of hardware mixers and recorders; and JACK, a low-latency audio server and application transport control interface for Linux and Mac OS X.
Professional audio recording hardware supports datatypes not commonly encountered in consumer-grade systems. A pro DAW can handle audio at greater bit depth, for deeper amplitude range and precision; at high sampling rates, for more accurate frequency resolution; and with greater flexibility in sound location and spatialization. It is not uncommon for professional recordists to work with 32-bit soundfiles recorded with a sampling rate of 96kHz, more than twice the resolution of compact disc audio.
Ardour is not a MIDI sequence recorder or editor. It knows nothing about music notation, and it is not designed to be a soundfile editor. Ardour has only a few built-in signal processing capabilities, and most of its processing power comes from its supported plugins. Finally, Ardour does not directly provide facilities for CD mastering and burning, but it is designed to work well with the excellent JAMin mastering suite.
The extent of your use of Ardour is limited fundamentally by the capabilities of your hardware. If a sound card or audio board is supported by the ALSA sound system, it should work with Ardour; however, standard consumer-grade audio devices are not suitable for using Ardour to its full extent. You can do great things with Ardour and a SoundBlaster Live, but for professional work, Ardour is happiest with a multichannel digital audio interface, such as the RME Hammerfall and M-Audio Delta cards.
Do your homework before purchasing your audio interface. Check the ALSA site for up-to-date news regarding supported systems, and try to find others who can comment on the suitability of a particular card. Ardour can respond to MIDI parameter control, so study the MIDI implementation charts for any external equipment you plan to use. See if your mixer specifications support MMC or MTC. Ardour is designed to work with automated mixer control surfaces, but again, your equipment has to support the features.
The question of a sufficient base computer system often pops up on the Ardour users mailing list. Satisfactory results have been reported with a 500MHz CPU, but such a system is too limiting for professional use. A fast CPU ensures accurate synchronization while recording or playing multiple audio tracks, and it is absolutely necessary if you intend to use many effects. For example, a good reverberation effect can be intensely CPU-hungry. You also should have a large, fast hard disk, properly tuned with the hdparm utility for maximum performance. Multiple tracks of streaming audio data absolutely require a powerful CPU and a fast hard disk to ensure perfect synchronization. Also, 32-bit digital audio files can be huge, and a typical recording session can create nontrivial storage demands. For professional use, you are advised to equip your system with two disks—one for your system and application software and one dedicated only to session audio storage. The Ardour Web site offers suggestions for specific CPUs, hard-disk specifications and even recommended motherboards. For best results with Ardour, follow the designer's advice.
Aaron Trumm's excellent article “The Linux-Based Recording Studio” [Linux Journal, May 2004] describes room considerations and the setup and configuration of external equipment needed for serious recording. Rather than rehashing Aaron's recommendations, I simply refer readers to that article for advice on selecting microphones, mixers, monitor speakers and other outboard gear.
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