Setting Audio Options


Before you record audio into Logic, we need to address some basic functions and features. Think of Logic as being like a high-end professional camera. It offers a lot more features and flexibility than that cheap throwaway. You have many more options that give you control over the final image. Before you snap the picture, however, you need to make sure that all the settings are just right so that they'll create the best possible image. In Logic, some options are set just once, before you start to record, while others may need changing during the process of creating your song. You'll choose some settings based purely on personal preference. Nevertheless, it's best to think through all your choices before beginning your work.

Choosing a Sampling Rate

We first addressed sampling rate in Lesson 4, "Editing Audio Regions," when you used the Sample Editor to convert the HH.aif file from 48 kHz to 44.1 kHz to match the sampling rate of the song. It is extremely important that you are aware of your song's sampling rate setting, because it greatly affects your computer's performance. Logic can support sampling rates of up to 192,000 samples per second, but a rate that high takes well over four times the disk space and four times the digital signal processing power as the 44,100 samples per second used for this song. You must also make sure that the sampling rate you've selected in Logic is compatible with the audio interface you are using. Most audio interfaces support 44,100 samples per second (44.1 kHz), so you should be fine using the 44,100 setting when recording audio in this lesson.

1.

Choose Audio > Sample Rate.

This song is already set to 44100 (44.1 kHz). There's no need to change anything. However, keep sampling rates in mind when you do your own recordings, because the song's sampling rate is used as the sampling rate for your recorded files.

2.

Leave the Sample Rate set to 44100.

Setting the Bit Resolution

Logic can record using 16- or 24-bit resolution. The higher the bit resolution, the more accurately Logic can represent the audio waveform. Using 24- instead of 16-bit resolution will require more processing power from your computer's CPU and take slightly more disk space when you start to record audio. However, with the current generation of technology, 24-bit recording has become quite standard.

1.

Choose Audio > Audio Hardware & Drivers.

The Preferences window opens to display the Audio pane, with the Drivers tab selected.

NOTE

If you're using Logic Express, your Drivers tab will look different than the figure below, which was taken in Logic Pro. However, all of the preferences covered in this section are available in Logic Express, so you can still work through the following steps.

2.

Select the 24 Bit Recording check box.

You need to make a few more settings in this window before recording, so let's leave the Preferences window open for the time being.

Setting the I/O Buffer Size

Logic's buffer setting controls how big a bite the computer tries to chew at one time when working with audio. This setting, which is measured in samples, can dramatically change the way in which your system performs, especially when recording. Typically, the bigger the buffer size, the more recorded channels of audio can be played at the same time, and this reduces the processing power required by your computer's CPU.

However, bigger buffers make the system react more slowly when recording. For example, with a large buffer setting you may notice an audible delay between playing a note on your MIDI controller and hearing one of Logic's Audio Instruments react to that note. This delay is called latency, and it can also seriously affect your audio recordings. For example, you may sing a note into a microphone and then experience a delay before hearing it through the speakers. Should this happen, you'll need to use a smaller buffer setting. But it's a trade-off, because a smaller buffer setting forces your computer's CPU to work harder, which means that fewer total audio tracks, plug-ins, and Audio Instruments can play simultaneously.

With these considerations in mind, start with a buffer setting of 64. If you later find you need more tracks, plug-ins, or Audio Instruments, you can increase the buffer size.

1.

In Logic's Preferences window, make sure the Audio pane's Driver tab is selected.

Near the top of the Core Audio tab is an I/O Buffer Size menu.

2.

From the I/O Buffer Size pop-up menu, select 64.

An Alert dialog pops up and asks you to reboot Logic. However, you don't have to actually restart the program.

3.

On the Alert dialog, click the Try (Re)Launch button.

Logic automatically reinitializes the Core Audio, and your driver settings are enabled.

Leave the Preferences window open for the next exercise.

Enabling Software Monitoring

When you're recording an audio track, software monitoring allows you to hear the signal in your speakers after it has passed through all the Audio Input, Track, and Output Objects you have created in Logic's environment. This enables you to hear how settings such as level, panning, and plug-ins affect the audio as you are recording it. The potential drawback is that since you are recording the audio live, the computer can't look ahead at what's coming. If you have a slower computer or are using large buffer settings, you may notice a delay between when the audio is created and when you hear it.

1.

In Logic's Preferences window, make sure the Audio pane's Drivers tab is selected.

Near the bottom of the Core Audio tab is a Software Monitoring check box.

2.

If the Software Monitoring check box is not already selected, select it now.

Leave the Preferences window open for the next exercise.

Selecting a File Type

When Logic records audio, the audio is stored as PCM (pulse-code modulated) audio files on your computer's hard drive. These are simply uncompressed audio files, and Logic can create your choice of WAV, AIFF, or SDII PCM audio. AIFF files are the most common type of uncompressed audio files on the Macintosh, so let's choose AIFF as the file type for recording.

1.

In the Preferences window's Audio pane, select the General tab.

2.

Make sure the Recording File Type menu is set to AIFF.

3.

Close the Preferences window.

Specifying a Record Path and Name

Unlike MIDI data, which is stored directly within the Logic song file, audio files are stored separately on your computer's hard drive. Audio files can be kept anywhere on your hard drive, though typically you should record to an Audio Files folder located in the same directory as your Logic project file. This type of file management makes it easy to find the files recorded for your song, and it also simplifies the process of backing up songs once you're done, because all the audio files are right there beside the project file. However, Logic provides you with full control over where audio files are recorded by allowing you to set your audio record path.

Each audio file you record needs a unique filename. Instead of manually naming each one, you can have Logic automatically use the name of the track as the filename. Logic will automatically add numbered extensions to the filename to prevent duplicates when you record on the same track multiple times.

Let's specify an appropriate record path and file-naming convention for your audio files.

1.

Choose Audio > Set Audio Record Path (Logic Pro users can press the A key).

The Set Audio Record Path dialog opens.

2.

At the top of the Set Audio Record Path dialog, select the Use Audio Object Name for File Name check box.

NOTE

Having Logic use the Audio Object name as a basis for filenames is especially useful when you're recording multiple tracks at the same time.

3.

In the "Core Audio recording path" area, click the Set button.

A dialog drops down from the Set Audio Record Path dialog's title bar.

4.

Navigate to the Lesson 8 Project Files > Audio Files folder.

5.

In the Save As text field, type an initial name for your audio recording.

6.

Click the Set button.

The Audio Record Path is set and all new files will be recorded into the Lesson 8 Project Files > Audio Files folder.

TIP

If you do not choose a record path ahead of time, you will be prompted to choose a record path the first time you record-enable an audio track.

7.

Click OK to confirm your settings and to close the Set Audio Record Path dialog.

Selecting Auto Input Monitoring (Logic Pro Only)

An audio track either can output the Audio Regions it finds as the SPL moves across them, or it can output the signal it receives from its input. Typically you want to hear the Audio Regions during playback and hear the input in the following two situations: when the track is record-enabled but the Transport is still (so you can set levels), and when the Transport is moving and in Record mode (which is the actual act of recording). Enabling Auto Input Monitoring automatically switches between the signals that are to be monitored, depending on the conditions just described.

Since this automatic switching is very helpful, let's go ahead and select Auto Input Monitoring.

1.

Make sure that the Audio > Auto Input Monitoring option is selected.

Choosing a Maximum Recording Time

When you record audio in Logic, a Progress dialog pops open to tell you how long you can record. By default, you are able to record for only 15 minutes. This is a small safeguard that keeps you from filling up your hard disk with accidental recordings, but you can change this maximum recording time if necessary. To do so, visit the Set Audio Record Path dialog and deselect the Maximum Recording Time check box, or enter a new maximum recording time in the text box immediately underneath this setting.

Additionally, even with this setting off you may not have enough time to record, for example, a full 80 minutes' worth of audio, and this can make it difficult to master a CD-Audio disc in Logic. For example, if you are recording at 120 bpm, Logic will allow you to record only 71:16 minutes of audio. Happily, there's an easy answer. Due to the way Logic's sequencer works, each song can be a maximum of 2,158 bars in duration. Consequently to gain more recording time, just halve the bpm of your song! The available recording time will double.


Enabling the Replace Mode

In most cases when you are recording, you'll want to use something called the Replace mode. This simply means that when Logic is recording onto a track, any information on that part of the track is overwritten with a new Object. In other words, Logic behaves like a regular audiocassette recorder. However, Logic does not rewrite or delete the previously recorded audio on the hard driveit's still part of the audio file and you can get it back at any time. This gives a huge advantage over the cassette recorder: You can always undo your recording and go back to where you were before!

NOTE

Recording without the Replace mode can get very confusing. Without Replace engaged, Logic will present multiple recorded Objects on the same track. In an audio track, only one of these Objects can be heard at a time. But in a MIDI track, multiple Objects can be heard from the same track. Sometimes the Objects overlap to the point where you may be hearing things that you can't see in the Arrange window.


  1. Click the Replace button in the Transport panel. (The Tool Tip for this button says Toggle Erase Mode, but don't get confusedit is the Replace Mode).



    Apple Pro Training Series Logic Pro 7 and Logic Express 7
    Apple Pro Training Series: Logic Pro 7 and Logic Express 7
    ISBN: 032125614X
    EAN: 2147483647
    Year: 2005
    Pages: 197
    Authors: Martin Sitter

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