Digital Recording


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.

For more information, see:

Chapters 34: Connect and configure your equipment

Chapter 7: Add signal processing to sweeten your sound or add compression and effects

Chapter 10: Mix sources together and edit and arrange your sound

Chapter 13: Record on the fly during a performance


Setting Levels

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).


Headroom

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.


Get the right levels:

Analog: 0 dB, or a little more or less

Digital: Approaching but never crossing 0 dB


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.

Distortion

"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

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.

Recording Methods

Whether you're using a simple cassette multitrack recorder or a sophisticated pro digital studio, there are several different approaches to recording:

  • Simple recording: Basic recording involves recording one mono or stereo signal at a time: click/press Record, then click/press Stop.

  • Overdubbing : Overdubbing is the addition of tracks, one or more at a time, on top of existing material, which remains unchanged. You can overdub with any software that supports multitrack playback, including Audacity and any DAW.

  • Simultaneous multitracking: As opposed to sequential overdubbing, multitracking is the recording of two or more discrete inputs (one drum track and one guitar track, for example) at the same time. On a computer, this is accomplished with a multichannel audio interface and multitrack recording software or DAW.

  • Punch recording: Punch recording involves beginning to record at a point other than the beginning of the song, "punching in" (starting recording), and then " punching out" (stopping recording), often replacing other material in the same track. For instance, if you have a perfect take but don't like one bar, set the punch in and out points to that bar and record only over it.

  • Looped recording: Even if your music doesn't involve loops , looping can make recording easier. For instance, if you need a "perfect" take of a four-bar phrase, loop that four-bar phrase using an application that supports multiple takes, and keep recording takes over the loop.

  • Sampling: Sample-based software takes the idea of looped recordings one step further: using a sample recorder or an application like Ableton Live, you can record and play back takes on the fly, even in a performance.

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:

  1. Set your input device(s) for the program.

  2. In a multitrack application, set the audio input for the track you want to use.

  3. Arm the track: record-enable it so it's ready to record. (Some software automatically monitors any record-enabled track; if yours sets monitoring manually, set up monitoring on the track, too.)

  4. Set the playback position to the beginning of your project, or set the in and out points for punch recording.

  5. Click Record!

On the DVD: Audacity multitrack recorder (free, Mac/Windows), Ableton Live audio workstation (save-disabled demo, Mac/Windows)


Let's take a look at some hands-on examples using Audacity and Ableton Live, as included on the DVD.

Audacity

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.

Similar environments: You'll find basic waveform-level recording in applications like BIAS Peak and Deck (Mac), Sony Sound Forge (Windows), and Adobe Audition (Windows).


Ableton Live

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 ):

  1. Make sure your inputs and outputs are visible in Session View (View > In/Out).

  2. Select an input for an individual track, making sure the input's meters are active. (If not, double-check your connections and hardware and software settings.)

  3. Arm the track in the view you want to use:

    Arrangement View: For linear recording into your arrangement, arm the track in Arrangement View.

    Session View: If you want to record a clip into a clip slot for later use (either looped or as a triggered file), arm the track in Session View.

    Similar environments: DAWs like Pro Tools, Cubase, Logic, and DP also feature mixer and arrangement views and mixer-style record-enable buttons, although the clip approach to on-the-fly sampling is specific to Live.


  4. Record into your arrangement or clip slot:

    Arrangement View: Click Record in Live's transport controls. When you're done, click Stop.

    Session View: Click the Record button of the slot into which you want to record. When you're done, click the Clip Stop button.

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.




Real World Digital Audio
Real World Digital Audio
ISBN: 0321304608
EAN: 2147483647
Year: 2006
Pages: 96
Authors: Peter Kirn

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