Apple MB792Z/A User Manual - Page 1231

Note: When setting an output device which also provides inputs, the Input Device setting changes accordingly. If choosing a different input device, you will be recommended to use a common Word Clock for both audio devices, in order to ensure the best sound quality. • Input Device pop-up menu: Allows you to choose between any installed Core Audio device, including the internal sound hardware. This also includes aggregate audio devices, consisting of several audio interfaces. See the Audio MIDI Setup Help for information on aggregate devices. • I/O Buffer Size pop-up menu: This parameter determines the size of the buffer used by the audio hardware for both input and output. The smaller the buffer size, the less latency you will encounter when monitoring while recording, or using software instruments. Some points to note: • As this parameter value is reduced, it places a higher strain on your system's processor or processors. • There may be a point where the selected I/O buffer size is too small for your system, and begins to affect playback. This usually takes the form of clicks, pops, and crackles in your audio. • You should aim for the lowest possible I/O buffer size value that doesn't introduce clicks, pops, and crackles in your audio. Tip: If you find that a higher I/O buffer size setting provides suitably low latency during record monitoring and software instrument playback, you should use it. This will minimize the impact on your system's processor or processors. • Resulting Roundtrip Latency/Resulting Output Latency display: Displays either the resulting roundtrip latency or the resulting output latency for the current I/O buffer size. Click the display to toggle between the two values. • Recording Delay slider: Allows you to delay the recording of audio by a certain fixed value, helping you to compensate for any information delays that are caused by the audio driver. Note: You should not normally need to touch this parameter. • Universal Track Mode checkbox: Universal Track Mode is turned on by default. It allows you to play back stereo and mono regions on a single track. It should be left on. • 24 Bit Recording checkbox: When this setting is turned on, Logic Express can record 24-bit files. 20- or 24-bit recordings offer a significant improvement in the available dynamic range, but require high-quality peripheral components such as microphones and pre-amps, not to mention high-quality analog-to-digital/digital-to-analog converters. 20- and 24-bit files use one-and-a-half times the disk space of comparable 16-bit files. Chapter 43 Preferences in Logic Express 1231