With your microphones in place, you're ready to begin recording to disk. Double-check the input and output settings in your software first. On Mac OS X, look for preferences under the application menu (the menu with the name of the program, like Audacity or Live), and on Windows select File > Preferences. You can then proceed to record.
With an input enabled, you'll need to make sure you have the right input level. If the signal is too weak, the recording will be too quiet, and amplifying it to an audible level will add noise. If the signal is too strong or "hot," it can cause distortion. By setting your input gain so that the level saturates your dynamic range without distorting, you'll get the cleanest possible recording. This means you need to watch your meters while you're recording and make appropriate adjustments as needed ( Figure 6.23 ).
Figure 6.23. Watch your meters (left) to set the right level. If you need to, adjust input gain in your hardware or software, as shown here in Audacity (right).
Every device has a dynamic range (the amplitudes it can accommodate from minimum to maximum). On analog equipment, there's an additional range above the maximum recommended level (labeled on a meter as 0 dB), up to the level at which signal significantly distorts or clips . This range is often colored red on equipment meters. If you've ever gone "into the red," you've exploited the additional range, which is called dynamic headroom ( Figure 6.24 ).
Figure 6.24. Analog signal (left) has additional headroom beyond 0 dB, but anything above 0 dB on a digital meter (right) will result in digital clipping.
On analog equipment, you'll want your meters to read approximately 0 dB as often as they can, with an occasional excursion slightly "into the red." Meters on analog equipment can show a little bit of clipping when the signal isn't actually significantly distorting. Digital equipment works differently: because amplitude is stored as a number and not as a continuous voltage, its maximum is really its maximum. Generally speaking, digital equipment doesn't have any dynamic headroom; therefore, you'll have to set your inputs so that your levels get near the 0 dB threshold without crossing it.
"But wait," you may be saying, "I love distortion!" Odds are, you like analog distortion, a "fuzzy," warm sound generated by analog equipment pushed just past its headroom. From distortion pedals to "overdriving" recorded tracks, musicians have long made use of slight overdrive (pushing a device just past its amplitude maximum) to get a desired effect.
Digital devices distort differently: instead of rounding off the top of a waveform as it passes beyond the amplitude maximum, they slice off the tops of the sound waves, creating a straight line ( Figure 6.25 ). This result is called digital clipping , and it's almost never desirable. In fact, if you want to achieve analog-style distortion, you'll need software that can emulate the result. (See Chapter 7 for more on this effect.) Unless you want the specific and unpleasant sound of digital clipping, make sure your digital meter never crosses the upper threshold. The signal input level can't generally be turned down once the signal has entered the computer; if it's too hot, you need to turn it down at the source or adjust the input trims on your audio interface.
Figure 6.25. A saturated digital signal makes maximum use of the full amplitude range of the recording (top). But go beyond the maximum, and digital clipping will occur (bottom), as shown here with a sine wave.
Monitoring , listening to the sound that's being recorded, is key to a successful recording. If you're recording on top of existing tracks, you'll need to hear both those tracks and the live sound in order to play with tight timing. You can monitor the live sound through the computer as you're recording, but latency introduced as a signal routed into and out of the computer can make timing difficult. Some interfaces offer direct monitoring features that route zero-latency audio directly from the interface's input to headphones plugged into the interface. Lexicon's Omega, for instance, even lets you adjust the mix of what's coming directly from your mic or instrument and what's coming from your computer ( Figure 6.26 ). Other interfaces have options available in their software driver control panels.
Figure 6.26. The monitor mix knob on the Lexicon Omega computer audio interface lets you listen exclusively to the sound you're recording (direct), exclusively to the audio from your computer (playback), or to an adjustable mix of the two.
If you don't have an interface with this feature, you can also set up zero-latency monitoring using a mixer. Plug your headphones and the sound source you want to record into this device, route the output from your computer to the mixer, and then record the new track by routing its signal from the mixer to your interface using an aux send. (If you record the mixer's main output, your new track will have the previously recorded tracks embedded into it.)
Audio applications can also give you the option of turning monitoring on or off: Ableton Live's "Monitor" can be set to monitor inputs only when the track is armed (Auto), or it can be manually enabled or disabled.
Whether you're using a simple cassette multitrack recorder or a sophisticated pro digital studio, there are several different approaches to recording:
Hands-on: Roll It!
Now you're ready to record in your application of choice. The basic workflow in any application goes something like this:
Let's take a look at some hands-on examples using Audacity and Ableton Live, as included on the DVD.
Once your inputs are set up, recording in Audacity is as simple as clicking the Record button on the transport. Each new recording take will add an additional track ( Figure 6.27 ). You can use this to store multiple takes, saving the one you like, or to create a mix of multiple recordings. Use the Solo and Mute buttons to choose which tracks to hear.
Figure 6.27. Overdubbing mono tracks in Audacity. New tracks will be added on the bottom with each new take.
Ableton Live (www.ableton.com) is more typical of the multitrack recording interface in a DAW. Since Live displays level in inputs before you select them, it's easy to tell whether the input on your interface is live. Live's first tutorial will familiarize you further with the application and recording.
Live can record audio (and MIDI) in one of two ways ( Figure 6.28 ). You can record whole tracks in linear fashion, just as you might in another DAW, by using the Arrangement View . Unique to Live is a second option: you can record individual audio/MIDI samples into clips, which you can manipulate and play back in real time for faster studio work or even a live performance. Either is a valid way to work, and you can move clips back and forth between the two views, so you don't have to choose one or the other permanently.
Figure 6.28. Ableton Live is structured to let you work through a linear song structure or a collection of clips to be triggered individually or in groups. Record audio into an overview of your song in Arrangement View (left), or record into a clip slot in Session View (right).
Either way, once you're ready to record in one of these two views ( Figure 6.29 ):
Figure 6.29. To record in Live, first set up your inputs and arm (record-enable) your track (left); then either click the record button on a clip slot in Session View (top) or click the Record Transport button at the top of the screen in Arrangement View.