You are here

FREE Audio Units Host App

Apple Notes By Mark Wherry
Published October 2005

AU Lab is a comprehensive Audio Unit host application supplied free with Apple's developer tools, which come with every copy of Mac OS X.AU Lab is a comprehensive Audio Unit host application supplied free with Apple's developer tools, which come with every copy of Mac OS X.

We explore a powerful Audio Units plug-in host application you might not realise you already own, called AU Lab. Plus news of the multi-button Apple mouse and Intel architecture changes...

Long-term Mac fans might be feeling slightly unsettled lately, following June's announcement of a transition to Intel chips. While the actual details of products Apple will put out using Intel's processors are speculative at this point, there were some interesting announcements at the Intel Developer Forum (IDF) conference this month concerning what Intel term their 'next-generation micro-architecture' (see 'The Next Generation' box). This month also saw the release of a product many Mac users also thought they'd never see from Apple: a mouse with more than one button — the somewhat bizarrely-named Mighty Mouse....

Off To The Lab

Ever since the introduction of Mac OS X, Apple have supplied a suite of development tools with every copy of the OS, and while those not wanting to develop their own software often overlook this, the package features many interesting tools, such as AU Lab. Although originally intended to allow developers to test their Audio Units plug-ins in a host environment, AU Lab is actually quite a powerful stand-alone mixer for running instrument and effects plug-ins, and would be useful for anyone looking to set up a second Mac for running Audio Units. If this sounds like you and you haven't installed the developer tools already, run the Xcode Tools installer in the 'Applications/Installers /Xcode Tools' folder, and once the installation has finished, you'll find AU Lab in the 'Developer/Applications/Audio' folder.

When you run AU Lab, you'll be prompted to create a new document by specifying the Audio Device and how many input and output channels you want to use. Stereo and mono channel layouts are supported. After this, AU Lab will open a mixer window showing master channel strips for your output channels, and automatically creates audio input channels for any inputs you added. Audio input channels allow audio to be streamed into the mixer from your audio device, and you can then process the signal with a number of Audio Units insert effects. (I added about 12 inserts as a test and could have added more, so I'm not sure what the actual physical limitation is here.) In addition to running insert effects on an audio channel, you can also create busses with insert effects and then set up send-and-return style effects.

You can add additional audio input channels (but not additional master out channels) later, if you want to, from the Edit menu, and if you're not looking to process an external audio source you can create Audio Unit Instrument and Audio Unit Generator channels to run these types of AU plug-ins, also from the Edit menu.

When you add an Audio Unit Instrument, AU Lab will prompt you to set a MIDI input source (which could be a port on your MIDI Interface or a Network Session, using Tiger's new MIDI Network features), a group name and colour you want to assign to the mixer channel strip that will be created, and the actual Instrument plug-in you want to use. When you're working in an Audio Unit Instrument's editor, you can switch to a special MIDI Editor view by clicking on the pop-up menu in the top-right corner of the Plug-ins Editor window. Here you can filter and transpose incoming MIDI data, as well as limiting keyboard and velocity ranges, for setting up master keyboard-style functionality.

AU Lab is starting to sound too good to be true, as it also has built-in transport controls and can be slaved to an external MIDI Clock source for tempo-related effects. You can even set up MIDI maps for mapping controllers to Audio Unit parameters. Well worth checking out if you need an Audio Unit host application!

Mighty Good?

The fact that Apple's mice have always had one button has often been a topic for debate, especially since Mac OS 8 officially introduced the idea of a context menu that would be triggered by clicking with the Control key held down — a function more conveniently accessed by using the second mouse button on a third-party mouse. Indeed, for this reason I would guess that the majority of Mac users reading this column aren't using an Apple-supplied mouse with their Mac, and probably wouldn't want to do without a two-button mouse, or a scroll-wheel.The Mouse System Preference Panel enables you to configure the behaviour of your Mighty Mouse.The Mouse System Preference Panel enables you to configure the behaviour of your Mighty Mouse.

So, to respond to the demands of users who want more functionality without compromising on the simple-to-use design, Apple have released the Mighty Mouse, which takes the same basic shape as the old Pro Mouse but is perhaps better compared to the look of Apple's Bluetooth model, featuring, as it does, a solid white exterior. Like the Pro Mouse, the Mighty Mouse is an optical mouse and connects to your Mac via USB (although it is also Windows-compatible). Where it differs from the Pro Mouse is in offering four different buttons, plus a scroll wheel that works both horizontally and vertically — although, on first inspection, it appears that the mouse only has one button. And while this sounds like a contradiction, it turns out to be true: the Mighty Mouse does, indeed, only have one physical button.

Rather than using multiple physical buttons, the Mighty Mouse uses sensors to detect where your fingers are placed and makes an assumption about which mouse button you actually pressed when you click the mouse. Therefore, if you click the left side of the mouse, this is the normal, primary, left button, whereas if you click the right side, this is the secondary, right button. Clicking with your finger on the scroll wheel offers a third button, while the fourth button is accessed by squeezing two additional sensors on either side of the mouse. Cleverly, the side 'button' is disabled if you lift the mouse off the desk, so you're not accidentally going to activate it when moving the mouse around.

If this all sounds a bit bizarre to you, you're literally right, as the Mighty Mouse also makes audible 'gestures'. If you unplug the mouse you'll realise that the scroll wheel is actually silent: the clicking scroll-wheel sound that you hear in normal operation is actually simulated, as is the clicking sound you hear when you squeeze the sides of the mouse.

Getting the Mighty Mouse up and running is easy: although its basic functions work out of the box (the primary button and the scroll wheel), you need to install the supplied additional software to access everything else, and preferably also be running Mac OS 10.4.2. The Mighty Mouse will work with earlier versions of Mac OS X, although it's worth checking on Apple's web site to see what functionality you'll be able to access with an earlier version. Once you've installed the Mighty Mouse software, you'll be able to configure it in the normal Mouse System Preference Panel, where you can assign additional tasks to the buttons — activating Dashboard, Exposé, Spotlight or the Application Switcher, for example — and enable or disable either horizontal or vertical scrolling.

In use, I have to confess that I found the Mighty Mouse a bit awkward. Firstly, my natural habit for a two-button mouse is to rest my fingers on the buttons, making it easy to click the appropriate one, but this confuses the Mighty Mouse. In order to activate the different buttons you consciously have to ease the 'other' (unused) finger slightly off the surface, so that the mouse doesn't get confused. Also, while the audio gestures aren't annoying, the scroll wheel is pretty sensitive, and the squeeze button also feels a little unnatural. For these reasons, I do recommend trying the Mighty Mouse in a shop before buying. If you're used to third-party mice, such as Microsoft's Intellimouse range, you might not get along with Apple's new offering.

I bought a Mighty Mouse because I needed a multi-button mouse for my recently purchased G5 and, to be fair, after two weeks of use I was finally getting used to it. Whether you want to put in the familiarisation time is a personal decision. The Mighty Mouse is available now for £35 and is not currently bundled as standard with new Macs.

The Next Generation: Intel's New 'Micro-architecture'

Simply put, a micro-architecture is the technology used in a processor to implement an instruction set, such as the x86 instruction set used in Intel's current Celeron, Pentium and Xeon processors. This is important because it means that the underlying technology in a processor can change, but as long as the instruction set remains the same all current x86 software be compatible. According to Intel, their new micro-architecture is scalable, with multiple cores, bringing together technology from their high-performance Netburst and energy-efficient mobile micro-architectures to produce a chip that offers high performance and low power consumption.

Intel intend to release three processors featuring the new micro-architecture, code-named Merom, Conroe and Woodcrest, by the middle of next year, for the mobile, desktop and server markets respectively. This time-line, one might speculate, coincides with the preliminary schedule discussed at Apple's own developer conference for the release of the first Macs with Intel processor. Although an x86 version of OS X wasn't demonstrated at the Intel Developer Forum, a laptop with a dual-core Merom processor was demonstrated, running Windows XP 64-bit edition. That system was actually used to run the whole keynote presentation, along with a dual-core Conroe running Fedora Linux. A system featuring two dual-core Woodcrest processors was shown running Windows Server 2003.

Although the specifics of the new micro-architecture weren't available at the time of writing, Intel listed its main features on their web site. These included higher performance Out of Order execution (where a processor basically executes instructions in the most efficient way possible, to avoid wasted cycles, rather than in the explicit order of the program), an enhanced cache system for multiple cores, and — of most interest to those running audio software — improved memory bandwidth utilisation and improved SSE performance. SSE is the Intel equivalent of the Power PC's Velocity Engine (also known as Altivec), which is used intensively for optimising DSP operations.

The IDF also hosted its first ever Mac OS X session, where Intel confirmed that they will provide a beta version of the company's developer tools as Xcode plug-ins later this year.