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Apple Places Audio At Its Core

by David Fox

Apple's Macintosh computers are widely used for broadcast audio, but setting it up hasn't always been simple. Now, rather than seeing audio as an add-on, Apple has integrated it into its new, more stable, Unix-based operating system, OSX.

"Instead of needing a professional application to play back high quality audio, you can now do that kind of thing from the desktop," because OS X has proper audio handling built in, says Apple's audio consultant, sound designer/engineer, Paul Wiffen. This means that any application can have high quality audio, such as Premiere.

Core Audio "intelligently handles everything as 32-bit floating point [code], but if it sees that it is 24/96 [24-bit/96kHz audio] it will, in real time, downsample to 16-bit 44.1 kHz to play back on the Mac's internal audio card," says Wiffen.

For nonlinear editing, this means users can have 24/96 quality files playing back on any Macintosh and can edit and process them on a laptop without having to downsample them first. "As soon as you go on to a system which supports higher levels, the edits are at full audio quality," he says. You only have to have the full system when capturing the audio and doing the final output, so most work can be done on lower-cost or portable systems. He advises keeping everything on removable FireWire hard drives, for complete portability. "You are no longer tied to the big system, so you can work at home or elsewhere without any file conversions," he says

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Overall, Apple claims OS X's audio performance is the best in desktop computing, with throughput latency (the time taken from audio input to output via the application) as low as 1 millisecond, compared to 10ms previously (Windows can take up to 15ms), which "rivals the performance of specialised audio hardware." This is across multiple channels, compared to two-channel stereo previously, without third-party applications, taking advantage of whatever output devices are plugged in.

It also supports plug-ins at OS level. This means that you just need to have one set of VST plug-ins, for example, to work with several different VST applications. Under OS 9, someone running Logic and Cubase needed to store a copy of each plug-in in each application, now they are all stored in the same central library. Digidesign's RTAS plug-ins, as used for Pro-Tools, also get their own central folder, as does Apple's new Component plug-in format which works with any application handling audio, no matter what plug-in format it normally works with. OS X comes with several Component plug-ins, such as reverb and EQ, allowing audio sweetening without any audio application. It also includes a virtual synthesiser for music. Many more are freely available on the Web.

Full MIDI support is also built into the OS, which will automatically recognise any standard MIDI or other audio device when it is plugged in, with no need for extra software.

JUNE 2002

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David Fox