Editing and mixing multiple tracks is a whole lot easier in the, digital realm than it is in the analog world. No waiting for tapes to rewind, no physically cutting and pasting tapes—it’s all just pointy-clicky bit shuffling. Although Audacity isn’t the most sophisticated application for heavy-duty multitrack recording and editing, you can make excellent mono and stereo recordings with it and even 5.1 and 7.1 surround sound. It’s the real deal, with discrete tracks.
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That’s as in separate, not as in able to keep a secret. Discrete is an important term in audio because it tells you when you’re getting the real deal, and not something simulated. For example, a surround sound hi-fi system will emulate 5.1 sound from a stereo recording, which has only two discrete channels. Real 5.1 has six discrete channels.
What is Audacity missing? It doesn’t have per-track recording level meters, and you can’t make edits while tracks are playing. When you’re using a multichannel recording device, you can’t control which input goes to which track. Multichannel surround mixing is still rather rudimentary: You can export to 5.1 and 7.1 surround, but Audacity gives you no help mapping the channels. Audacity’s strengths lie in recording, editing, and mixing for mono and stereo playback. Ardour might be a better choice for Linux and Mac users who want to perform heavy-duty studio wizardry, perform multichannel surround, and have maximum control, and of course Windows and Mac users have great thundering herds of other high-end audio production suites to choose from.
So, what can Audacity do? It will record as many channels at one time as your recording interface supports and your computer can handle. Some examples of multichannel recording interfaces are the M-Audio Delta 1010 PCI sound card (10 × 10), the Edirol FA-101 FireWire audio interface (10 × 10), the RME Hammerfall sound cards, and the M-Audio NRV10, which is a useful combination of an analog mixer and 10-channel FireWire DAC/ADC.
Audacity has no hard limit for the total number of tracks in a project; you can keep adding tracks until your computer keels over. Audacity supports all of the basic multitrack editing and mixing functions: mix and match clips, time-shift and synchronize, layer multiple copies of the same track or clip, do fix-its and special effects, and mixdown to any number of channels from 1 to 32 (WAV, AIFF, and Ogg Vorbis; other file formats support fewer channels). In real life, mono, stereo, and 5.1 surround (6 channel) are your likeliest options.
Let’s take a moment to be sure of our terminology. A single track in Audacity is represented by a single waveform, as in Figure 9-1. I call this a mono track to make it clear that it’s not a stereo track. However, the definition of track is a bit fuzzy in audio and also in Audacity because it treats a stereo track the same way it treats a mono track—even though there are two channels with two different waveforms, Audacity sees a stereo track as one track, and everything you do to it is applied equally to both channels. A track is also a single song in a track, CD, LP, or tape that contains several songs.
Figure 9-1. This is what a single mono track looks like—one waveform, no matter how many voices or instruments are recorded on the track.
Channel refers to audio inputs and outputs. When you record using a single mono microphone, that is a single input channel even if you have an entire orchestra playing and choir singing. Multichannel recording interfaces let you use more microphones and instrument plug-ins, which creates more tracks.
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The number of input channels in Edit > Preferences > Devices must match the number of your physical input channels.
You get the ultimate flexibility and control by giving every voice and instrument its own mic. Studio recording is nothing like live recording—sometimes every performer is in a separate soundproof cubicle, or recorded at different times and different locations, so the various band members might never even be physically present at the same time. It’s a common practice to use multiple mics on a single performer and then manipulate the resulting multiple tracks to create absolute perfect wonderfulness (or an overproduced glop, as the case may be).
Be careful with the physical recording inputs that you plug your mics and instruments into—some are mono, some will be stereo, some will require phantom power, and others will be for various other purposes. Be sure you’re plugging things in correctly—just because it fits doesn’t mean it’s right.
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A good habit to develop is to never hotplug anything, unless you are certain it is safe to do so. Don’t turn on phantom power until after your condenser mics are plugged in. Don’t plug anything into your amp, preamp, mixer, and so on with the power on, or at least make sure all volume controls are at zero. Turn power off before unplugging. Most audio equipment is tolerant of a certain amount of abuse. But pops from hotplugging are annoying and may damage your equipment.
If you use a stereo mic on a mono recording input, only one channel will record, and you’ll have a stereo track like the one in Figure 9-2 with one channel blank.
Figure 9-2. This is what happens when you plug a stereo microphone into a single-channel recording input.
No worries if this happens to you; just use the Track menu to separate a stereo track into two tracks, and then delete the empty one. There are two split track options: Split Stereo Track creates a left and a right track, while Split Stereo to Mono creates two mono tracks. (You can use this same menu to join two individual tracks into a single stereo track.) Assigning a track left, right, or mono is important when you mixdown to stereo: Left tracks go to the left channel, right tracks go to the right channel, and mono goes to both. (See Mixdown to Stereo in Mixdown to Stereo to learn more.)
Low-end onboard sound chips are notorious for claiming to have stereo microphone inputs, but then only one channel works. If you try a mono microphone on one of these, it may not work at all, so I can’t resist giving the obvious warning: Test it before you need it.
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See Chapter 2 for a refresher on setting up audio hardware, and consult your product documentation. Beware anyone who wants to “help” you! It’s your gear, and you don’t want the help of people who don’t know what they’re doing, which is quite a large number of folks who think they’re experts (such as professional musicians who have been on stage all their lives and rely on the old “whack it until something happens” technique). Your peace of mind and equipment are more important than their egos.
Output channels are like input channels. If you create a 5.1 surround mix that is six discrete channels—left, right, center, surround left, surround right, and low-frequency effects (LFE)—you could take a single mono track and export it to 5.1 surround, as Figure 9-3 shows. I don’t know why you would want to, but it’s there if you do. Audacity supports a maximum of 32 output channels. If you have a playback device that supports 32 channels, you will have yourself one heck of a fun time. A more realistic option for all those channels is to export them to a single 32-bit WAV file, or 32 individual WAV files (using File > Export Multiple), and then import them into a more sophisticated mixing application for advanced mixing and studio wizardry. For example, some users like to record and edit in Audacity and then do the final mix in a different program that does things Audacity doesn’t do, such as support MIDI, or that has more sophisticated multitrack mixing. Since Audacity is free, it doesn’t cost anything but some time to try different workflows.
Figure 9-3. An amusing example of creating a 5.1 WAV file from a single track using Audacity’s custom export mixer
Clips are segments of tracks. You can have a lot of fun with clips, such as changing what a person says in an interview by moving the words around, making loops, or grabbing clips from different recordings and blending them together in new and different ways. You can have several clips in a single track or put each one in its own track. You can even drag clips from one track to another using the Time Shift tool (Figure 9-4).
