When CD's were introduced to the public over a decade ago the advantages of digital audio over the more traditional analog recordings were, to say the least, obvious. And even if the earliest digital recordings lacked the kind of subtle nuances inherant in analog, they more than made up for it in other ways.

But just because a sound is recorded digitally doesn't mean that it'll magically lose any background noise that comes along for the ride while recording sounds from your favourite analog synth. Far from it. As soon as you click on the record button in the transport control panel of your favourite audio recording software, your hard disk is going to record it all. Bit by bit.

Enter Arboretum's Ionizer, an easy to use professional noise reduction and mastering system that has the kind of intuitive interface that makes processing audio fun. We took a short sample of an unborn childs heartbeat (recorded directly from the external speaker of a Sonargram using a Sony Microcassette recorder) and after launching our beta version of Hyperengine, the host application that runs all of Arboretum's audio processing software, we created a new file and recorded the sample directly from the Sony via the audio input into a Mac.

Under normal circumstances Ionizer makes it relatively easy to remove noises that have a consistant spectral "fingerprint", such as fans, hiss and hum, but within seconds we were able to remove all the elements of the original recording that we didn't need (which even included the sound of traffic going past outside the clinic window) and saved it as a new audio file ready to be used.

To give you and idea of what the cleaned up sample actually looks like, we analyzed it using Metric Halo's SpectraFoo digital metering software and as you can see Ionizer got rid of all the upper and mid range noise, which is where hiss usually hangs out.

Obviously cleaning up a recording of an unborn childs heartbeat is an unlikely application for a real time dynamic spectral reshaping tool, but we needed a sample that was so raw that the actual sound we needed was barely audible behind all the accompanying hiss and splutter.

You might find yourself using Ionizer's 512-band graphic equalizer to create infinitely variable filtering effects. Import a drum loop and use it to create a completely different groove. You'll also find that removing vocals or guitar parts is easy after a little practice.

The multiband dynamics processor is also perfect for use as a compressor, expander or limiter as well as the graphic equalizer, even all at the same time if you need it to do that. In fact every element of an audio sample can be made to do what you need it to do.

As far as compatibilty with the host computer is concerned Ionizer is Power Mac native which operates as a plug-in for any Premiere compatible audio application, including Adobe Premiere, Macromedia DECK II, Opcode Vision and Studio Vision, MOTU Digital Performer 2.1, Bias Peak, Emagic Logic Audio 3.0 and Gallery TurboMorph.

It can also run quite happily as a stand-alone application using Arboretum's HyperEngine shell (they send a copy with the software and it's also available free of charge from their website).

To contact Arboretum Systems check out their entry in our Manufacturers department.

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